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moodle/lib/dmllib.php

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<?php // $Id$
///////////////////////////////////////////////////////////////////////////
// //
// NOTICE OF COPYRIGHT //
// //
// Moodle - Modular Object-Oriented Dynamic Learning Environment //
// http://moodle.com //
// //
// Copyright (C) 2001-3001 Martin Dougiamas http://dougiamas.com //
// //
// This program is free software; you can redistribute it and/or modify //
// it under the terms of the GNU General Public License as published by //
// the Free Software Foundation; either version 2 of the License, or //
// (at your option) any later version. //
// //
// This program is distributed in the hope that it will be useful, //
// but WITHOUT ANY WARRANTY; without even the implied warranty of //
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the //
// GNU General Public License for more details: //
// //
// http://www.gnu.org/copyleft/gpl.html //
// //
///////////////////////////////////////////////////////////////////////////
/// This library contains all the Data Manipulation Language (DML) functions
/// used to interact with the DB. All the dunctions in this library must be
/// generic and work against the major number of RDBMS possible. This is the
/// list of currently supported and tested DBs: mysql, postresql, mssql, oracle
/// This library is automatically included by Moodle core so you never need to
/// include it yourself.
/// For more info about the functions available in this library, please visit:
/// http://docs.moodle.org/en/DML_functions
/// (feel free to modify, improve and document such page, thanks!)
/// GLOBAL CONSTANTS /////////////////////////////////////////////////////////
$empty_rs_cache = array(); // Keeps copies of the recordsets used in one invocation
$metadata_cache = array(); // Keeps copies of the MetaColumns() for each table used in one invocations
$rcache = new StdClass; // Cache simple get_record results
$rcache->data = array();
$rcache->hits = 0;
$rcache->misses = 0;
/// FUNCTIONS FOR DATABASE HANDLING ////////////////////////////////
/**
* Execute a given sql command string
*
* Completely general function - it just runs some SQL and reports success.
*
* @uses $db
* @param string $command The sql string you wish to be executed.
* @param bool $feedback Set this argument to true if the results generated should be printed. Default is true.
* @return string
*/
function execute_sql($command, $feedback=true) {
/// Completely general function - it just runs some SQL and reports success.
global $db, $CFG;
$olddebug = $db->debug;
if (!$feedback) {
$db->debug = false;
}
$empty_rs_cache = array(); // Clear out the cache, just in case changes were made to table structures
if (defined('MDL_PERFDB')) { global $PERF ; $PERF->dbqueries++; };
$result = $db->Execute($command);
$db->debug = $olddebug;
if ($result) {
if ($feedback) {
notify(get_string('success'), 'notifysuccess');
}
return true;
} else {
if ($feedback) {
notify('<strong>' . get_string('error') . '</strong>');
}
if (!empty($CFG->dblogerror)) {
$debug=array_shift(debug_backtrace());
error_log("SQL ".$db->ErrorMsg()." in {$debug['file']} on line {$debug['line']}. STATEMENT: $command");
}
return false;
}
}
/**
* on DBs that support it, switch to transaction mode and begin a transaction
* you'll need to ensure you call commit_sql() or your changes *will* be lost.
*
* Now using ADOdb standard transactions. Some day, we should switch to
* Smart Transactions (http://phplens.com/adodb/tutorial.smart.transactions.html)
* as they autodetect errors and are nestable and easier to write
*
* this is _very_ useful for massive updates
*/
function begin_sql() {
global $db;
$db->BeginTrans();
return true;
}
/**
* on DBs that support it, commit the transaction
*
* Now using ADOdb standard transactions. Some day, we should switch to
* Smart Transactions (http://phplens.com/adodb/tutorial.smart.transactions.html)
* as they autodetect errors and are nestable and easier to write
*/
function commit_sql() {
global $db;
$db->CommitTrans();
return true;
}
/**
* on DBs that support it, rollback the transaction
*
* Now using ADOdb standard transactions. Some day, we should switch to
* Smart Transactions (http://phplens.com/adodb/tutorial.smart.transactions.html)
* as they autodetect errors and are nestable and easier to write
*/
function rollback_sql() {
global $db;
$db->RollbackTrans();
return true;
}
/**
* returns db specific uppercase function
* @deprecated Moodle 1.7 because all the RDBMS use upper()
*/
function db_uppercase() {
return "upper";
}
/**
* returns db specific lowercase function
* @deprecated Moodle 1.7 because all the RDBMS use lower()
*/
function db_lowercase() {
return "lower";
}
/**
* Run an arbitrary sequence of semicolon-delimited SQL commands
*
* Assumes that the input text (file or string) consists of
* a number of SQL statements ENDING WITH SEMICOLONS. The
* semicolons MUST be the last character in a line.
* Lines that are blank or that start with "#" or "--" (postgres) are ignored.
* Only tested with mysql dump files (mysqldump -p -d moodle)
*
* @uses $CFG
*
* @deprecated Moodle 1.7 use the new XMLDB stuff in lib/ddllib.php
*
* @param string $sqlfile The path where a file with sql commands can be found on the server.
* @param string $sqlstring If no path is supplied then a string with semicolon delimited sql
* commands can be supplied in this argument.
* @return bool Returns true if databse was modified successfully.
*/
function modify_database($sqlfile='', $sqlstring='') {
global $CFG;
if ($CFG->version > 2006101007) {
debugging('Function modify_database() is deprecated. Replace it with the new XMLDB stuff.', DEBUG_DEVELOPER);
}
$success = true; // Let's be optimistic
if (!empty($sqlfile)) {
if (!is_readable($sqlfile)) {
$success = false;
echo '<p>Tried to modify database, but "'. $sqlfile .'" doesn\'t exist!</p>';
return $success;
} else {
$lines = file($sqlfile);
}
} else {
$sqlstring = trim($sqlstring);
if ($sqlstring{strlen($sqlstring)-1} != ";") {
$sqlstring .= ";"; // add it in if it's not there.
}
$lines[] = $sqlstring;
}
$command = '';
foreach ($lines as $line) {
$line = rtrim($line);
$length = strlen($line);
if ($length and $line[0] <> '#' and $line[0].$line[1] <> '--') {
if (substr($line, $length-1, 1) == ';') {
$line = substr($line, 0, $length-1); // strip ;
$command .= $line;
$command = str_replace('prefix_', $CFG->prefix, $command); // Table prefixes
if (! execute_sql($command)) {
$success = false;
}
$command = '';
} else {
$command .= $line;
}
}
}
return $success;
}
/// GENERIC FUNCTIONS TO CHECK AND COUNT RECORDS ////////////////////////////////////////
/**
* Test whether a record exists in a table where all the given fields match the given values.
*
* The record to test is specified by giving up to three fields that must
* equal the corresponding values.
*
* @uses $CFG
* @param string $table The table to check.
* @param string $field1 the first field to check (optional).
* @param string $value1 the value field1 must have (requred if field1 is given, else optional).
* @param string $field2 the second field to check (optional).
* @param string $value2 the value field2 must have (requred if field2 is given, else optional).
* @param string $field3 the third field to check (optional).
* @param string $value3 the value field3 must have (requred if field3 is given, else optional).
* @return bool true if a matching record exists, else false.
*/
function record_exists($table, $field1='', $value1='', $field2='', $value2='', $field3='', $value3='') {
global $CFG;
$select = where_clause($field1, $value1, $field2, $value2, $field3, $value3);
return record_exists_sql('SELECT * FROM '. $CFG->prefix . $table .' '. $select);
}
/**
* Test whether any records exists in a table which match a particular WHERE clause.
*
* @uses $CFG
* @param string $table The database table to be checked against.
* @param string $select A fragment of SQL to be used in a WHERE clause in the SQL call.
* @return bool true if a matching record exists, else false.
*/
function record_exists_select($table, $select='') {
global $CFG;
if ($select) {
$select = 'WHERE '.$select;
}
return record_exists_sql('SELECT * FROM '. $CFG->prefix . $table . ' ' . $select);
}
/**
* Test whether a SQL SELECT statement returns any records.
*
* This function returns true if the SQL statement executes
* without any errors and returns at least one record.
*
* @param string $sql The SQL statement to execute.
* @return bool true if the SQL executes without errors and returns at least one record.
*/
function record_exists_sql($sql) {
$limitfrom = 0; /// Number of records to skip
$limitnum = 1; /// Number of records to retrieve
$rs = get_recordset_sql($sql, $limitfrom, $limitnum);
if ($rs && $rs->RecordCount() > 0) {
return true;
} else {
return false;
}
}
/**
* Count the records in a table where all the given fields match the given values.
*
* @uses $CFG
* @param string $table The table to query.
* @param string $field1 the first field to check (optional).
* @param string $value1 the value field1 must have (requred if field1 is given, else optional).
* @param string $field2 the second field to check (optional).
* @param string $value2 the value field2 must have (requred if field2 is given, else optional).
* @param string $field3 the third field to check (optional).
* @param string $value3 the value field3 must have (requred if field3 is given, else optional).
* @return int The count of records returned from the specified criteria.
*/
function count_records($table, $field1='', $value1='', $field2='', $value2='', $field3='', $value3='') {
global $CFG;
$select = where_clause($field1, $value1, $field2, $value2, $field3, $value3);
return count_records_sql('SELECT COUNT(*) FROM '. $CFG->prefix . $table .' '. $select);
}
/**
* Count the records in a table which match a particular WHERE clause.
*
* @uses $CFG
* @param string $table The database table to be checked against.
* @param string $select A fragment of SQL to be used in a WHERE clause in the SQL call.
* @param string $countitem The count string to be used in the SQL call. Default is COUNT(*).
* @return int The count of records returned from the specified criteria.
*/
function count_records_select($table, $select='', $countitem='COUNT(*)') {
global $CFG;
if ($select) {
$select = 'WHERE '.$select;
}
return count_records_sql('SELECT '. $countitem .' FROM '. $CFG->prefix . $table .' '. $select);
}
/**
* Get the result of a SQL SELECT COUNT(...) query.
*
* Given a query that counts rows, return that count. (In fact,
* given any query, return the first field of the first record
* returned. However, this method should only be used for the
* intended purpose.) If an error occurrs, 0 is returned.
*
* @uses $CFG
* @uses $db
* @param string $sql The SQL string you wish to be executed.
* @return int the count. If an error occurrs, 0 is returned.
*/
function count_records_sql($sql) {
$rs = get_recordset_sql($sql);
if ($rs) {
return reset($rs->fields);
} else {
return 0;
}
}
/// GENERIC FUNCTIONS TO GET, INSERT, OR UPDATE DATA ///////////////////////////////////
/**
* Get a single record as an object
*
* @uses $CFG
* @param string $table The table to select from.
* @param string $field1 the first field to check (optional).
* @param string $value1 the value field1 must have (requred if field1 is given, else optional).
* @param string $field2 the second field to check (optional).
* @param string $value2 the value field2 must have (requred if field2 is given, else optional).
* @param string $field3 the third field to check (optional).
* @param string $value3 the value field3 must have (requred if field3 is given, else optional).
* @return mixed a fieldset object containing the first mathcing record, or false if none found.
*/
function get_record($table, $field1, $value1, $field2='', $value2='', $field3='', $value3='', $fields='*') {
global $CFG;
// Check to see whether this record is eligible for caching (fields=*, only condition is id)
$docache = false;
if (!empty($CFG->rcache) && $field1=='id' && !$field2 && !$field3 && $fields=='*') {
$docache = true;
// If it's in the cache, return it
$cached = rcache_getforfill($table, $value1);
if (!empty($cached)) {
return $cached;
}
}
$select = where_clause($field1, $value1, $field2, $value2, $field3, $value3);
$record = get_record_sql('SELECT '.$fields.' FROM '. $CFG->prefix . $table .' '. $select);
// If we're caching records, store this one
// (supposing we got something - we don't cache failures)
if ($docache) {
if (isset($record)) {
rcache_set($table, $value1, $record);
} else {
rcache_releaseforfill($table, $value1);
}
}
return $record;
}
/**
* Get a single record as an object using an SQL statement
*
* The SQL statement should normally only return one record. In debug mode
* you will get a warning if more record is returned (unless you
* set $expectmultiple to true). In non-debug mode, it just returns
* the first record.
*
* @uses $CFG
* @uses $db
* @param string $sql The SQL string you wish to be executed, should normally only return one record.
* @param bool $expectmultiple If the SQL cannot be written to conviniently return just one record,
* set this to true to hide the debug message.
* @param bool $nolimit sometimes appending ' LIMIT 1' to the SQL causes an error. Set this to true
* to stop your SQL being modified. This argument should probably be deprecated.
* @return Found record as object. False if not found or error
*/
function get_record_sql($sql, $expectmultiple=false, $nolimit=false) {
global $CFG;
/// Default situation
$limitfrom = 0; /// Number of records to skip
$limitnum = 1; /// Number of records to retrieve
/// Only a few uses of the 2nd and 3rd parameter have been found
/// I think that we should avoid to use them completely, one
/// record is one record, and everything else should return error.
/// So the proposal is to change all the uses, (4-5 inside Moodle
/// Core), drop them from the definition and delete the next two
/// "if" sentences. (eloy, 2006-08-19)
if ($nolimit) {
$limitfrom = 0;
$limitnum = 0;
} else if ($expectmultiple) {
$limitfrom = 0;
$limitnum = 1;
} else if (debugging()) {
// Debugging mode - don't use a limit of 1, but do change the SQL, because sometimes that
// causes errors, and in non-debug mode you don't see the error message and it is
// impossible to know what's wrong.
$limitfrom = 0;
$limitnum = 100;
}
if (!$rs = get_recordset_sql($sql, $limitfrom, $limitnum)) {
return false;
}
$recordcount = $rs->RecordCount();
if ($recordcount == 0) { // Found no records
return false;
} else if ($recordcount == 1) { // Found one record
/// DIRTY HACK to retrieve all the ' ' (1 space) fields converted back
/// to '' (empty string) for Oracle. It's the only way to work with
/// all those NOT NULL DEFAULT '' fields until we definetively delete them
if ($CFG->dbfamily == 'oracle') {
array_walk($rs->fields, 'onespace2empty');
}
/// End od DIRTY HACK
return (object)$rs->fields;
} else { // Error: found more than one record
notify('Error: Turn off debugging to hide this error.');
notify($sql . '(with limits ' . $limitfrom . ', ' . $limitnum . ')');
if ($records = $rs->GetAssoc(true)) {
notify('Found more than one record in get_record_sql !');
print_object($records);
} else {
notify('Very strange error in get_record_sql !');
print_object($rs);
}
print_continue("$CFG->wwwroot/$CFG->admin/config.php");
}
}
/**
* Gets one record from a table, as an object
*
* @uses $CFG
* @param string $table The database table to be checked against.
* @param string $select A fragment of SQL to be used in a where clause in the SQL call.
* @param string $fields A comma separated list of fields to be returned from the chosen table.
* @return object|false Returns an array of found records (as objects) or false if no records or error occured.
*/
function get_record_select($table, $select='', $fields='*') {
global $CFG;
if ($select) {
$select = 'WHERE '. $select;
}
return get_record_sql('SELECT '. $fields .' FROM '. $CFG->prefix . $table .' '. $select);
}
/**
* Get a number of records as an ADODB RecordSet.
*
* Selects records from the table $table.
*
* If specified, only records where the field $field has value $value are retured.
*
* If specified, the results will be sorted as specified by $sort. This
* is added to the SQL as "ORDER BY $sort". Example values of $sort
* mightbe "time ASC" or "time DESC".
*
* If $fields is specified, only those fields are returned.
*
* This function is internal to datalib, and should NEVER should be called directly
* from general Moodle scripts. Use get_record, get_records etc.
*
* If you only want some of the records, specify $limitfrom and $limitnum.
* The query will skip the first $limitfrom records (according to the sort
* order) and then return the next $limitnum records. If either of $limitfrom
* or $limitnum is specified, both must be present.
*
* The return value is an ADODB RecordSet object
* @link http://phplens.com/adodb/reference.functions.adorecordset.html
* if the query succeeds. If an error occurrs, false is returned.
*
* @param string $table the table to query.
* @param string $field a field to check (optional).
* @param string $value the value the field must have (requred if field1 is given, else optional).
* @param string $sort an order to sort the results in (optional, a valid SQL ORDER BY parameter).
* @param string $fields a comma separated list of fields to return (optional, by default all fields are returned).
* @param int $limitfrom return a subset of records, starting at this point (optional, required if $limitnum is set).
* @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
* @return mixed an ADODB RecordSet object, or false if an error occured.
*/
function get_recordset($table, $field='', $value='', $sort='', $fields='*', $limitfrom='', $limitnum='') {
if ($field) {
$select = "$field = '$value'";
} else {
$select = '';
}
return get_recordset_select($table, $select, $sort, $fields, $limitfrom, $limitnum);
}
/**
* Get a number of records as an ADODB RecordSet.
*
* If given, $select is used as the SELECT parameter in the SQL query,
* otherwise all records from the table are returned.
*
* Other arguments and the return type as for @see function get_recordset.
*
* @uses $CFG
* @param string $table the table to query.
* @param string $select A fragment of SQL to be used in a where clause in the SQL call.
* @param string $sort an order to sort the results in (optional, a valid SQL ORDER BY parameter).
* @param string $fields a comma separated list of fields to return (optional, by default all fields are returned).
* @param int $limitfrom return a subset of records, starting at this point (optional, required if $limitnum is set).
* @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
* @return mixed an ADODB RecordSet object, or false if an error occured.
*/
function get_recordset_select($table, $select='', $sort='', $fields='*', $limitfrom='', $limitnum='') {
global $CFG;
if ($select) {
$select = ' WHERE '. $select;
}
if ($sort) {
$sort = ' ORDER BY '. $sort;
}
return get_recordset_sql('SELECT '. $fields .' FROM '. $CFG->prefix . $table . $select . $sort, $limitfrom, $limitnum);
}
/**
* Get a number of records as an ADODB RecordSet.
*
* Only records where $field takes one of the values $values are returned.
* $values should be a comma-separated list of values, for example "4,5,6,10"
* or "'foo','bar','baz'".
*
* Other arguments and the return type as for @see function get_recordset.
*
* @param string $table the table to query.
* @param string $field a field to check (optional).
* @param string $values comma separated list of values the field must have (requred if field is given, else optional).
* @param string $sort an order to sort the results in (optional, a valid SQL ORDER BY parameter).
* @param string $fields a comma separated list of fields to return (optional, by default all fields are returned).
* @param int $limitfrom return a subset of records, starting at this point (optional, required if $limitnum is set).
* @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
* @return mixed an ADODB RecordSet object, or false if an error occured.
*/
function get_recordset_list($table, $field='', $values='', $sort='', $fields='*', $limitfrom='', $limitnum='') {
if ($field) {
$select = "$field IN ($values)";
} else {
$select = '';
}
return get_recordset_select($table, $select, $sort, $fields, $limitfrom, $limitnum);
}
/**
* Get a number of records as an ADODB RecordSet. $sql must be a complete SQL query.
* This function is internal to datalib, and should NEVER should be called directly
* from general Moodle scripts. Use get_record, get_records etc.
*
* The return type is as for @see function get_recordset.
*
* @uses $CFG
* @uses $db
* @param string $sql the SQL select query to execute.
* @param int $limitfrom return a subset of records, starting at this point (optional, required if $limitnum is set).
* @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
* @return mixed an ADODB RecordSet object, or false if an error occured.
*/
function get_recordset_sql($sql, $limitfrom=null, $limitnum=null) {
global $CFG, $db;
if (empty($db)) {
return false;
}
/// Temporary hack as part of phasing out all access to obsolete user tables XXX
if (!empty($CFG->rolesactive)) {
if (strpos($sql, ' '.$CFG->prefix.'user_students ') ||
strpos($sql, ' '.$CFG->prefix.'user_teachers ') ||
strpos($sql, ' '.$CFG->prefix.'user_coursecreators ') ||
strpos($sql, ' '.$CFG->prefix.'user_admins ')) {
if (debugging()) { var_dump(debug_backtrace()); }
error('This SQL relies on obsolete tables! Your code must be fixed by a developer.');
}
}
if (defined('MDL_PERFDB')) { global $PERF ; $PERF->dbqueries++; };
if ($limitfrom || $limitnum) {
///Special case, 0 must be -1 for ADOdb
$limitfrom = empty($limitfrom) ? -1 : $limitfrom;
$limitnum = empty($limitnum) ? -1 : $limitnum;
$rs = $db->SelectLimit($sql, $limitnum, $limitfrom);
} else {
$rs = $db->Execute($sql);
}
if (!$rs) {
debugging($db->ErrorMsg() .'<br /><br />'. $sql);
if (!empty($CFG->dblogerror)) {
$debug=array_shift(debug_backtrace());
error_log("SQL ".$db->ErrorMsg()." in {$debug['file']} on line {$debug['line']}. STATEMENT: $sql with limits ($limitfrom, $limitnum)");
}
return false;
}
return $rs;
}
/**
* Utility function used by the following 4 methods. Note that for this to work, the first column
* in the recordset must contain unique values, as it is used as the key to the associative array.
*
* @param object an ADODB RecordSet object.
* @return mixed mixed an array of objects, or false if an error occured or the RecordSet was empty.
*/
function recordset_to_array($rs) {
global $CFG;
if ($rs && $rs->RecordCount() > 0) {
/// First of all, we are going to get the name of the first column
/// to introduce it back after transforming the recordset to assoc array
/// See http://docs.moodle.org/en/XMLDB_Problems, fetch mode problem.
$firstcolumn = $rs->FetchField(0);
/// Get the whole associative array
if ($records = $rs->GetAssoc(true)) {
foreach ($records as $key => $record) {
/// Really DIRTY HACK for Oracle, but it's the only way to make it work
/// until we got all those NOT NULL DEFAULT '' out from Moodle
if ($CFG->dbfamily == 'oracle') {
array_walk($record, 'onespace2empty');
}
/// End of DIRTY HACK
$record[$firstcolumn->name] = $key;/// Re-add the assoc field
$objects[$key] = (object) $record; /// To object
}
return $objects;
/// Fallback in case we only have 1 field in the recordset. MDL-5877
} else if ($rs->_numOfFields == 1 && $records = $rs->GetRows()) {
foreach ($records as $key => $record) {
/// Really DIRTY HACK for Oracle, but it's the only way to make it work
/// until we got all those NOT NULL DEFAULT '' out from Moodle
if ($CFG->dbfamily == 'oracle') {
array_walk($record, 'onespace2empty');
}
/// End of DIRTY HACK
$objects[$record[$firstcolumn->name]] = (object) $record; /// The key is the first column value (like Assoc)
}
return $objects;
} else {
return false;
}
} else {
return false;
}
}
/**
* This function is used to convert all the Oracle 1-space defaults to the empty string
* like a really DIRTY HACK to allow it to work better until all those NOT NULL DEFAULT ''
* fields will be out from Moodle.
* @param string the string to be converted to '' (empty string) if it's ' ' (one space)
* @param mixed the key of the array in case we are using this function from array_walk,
* defaults to null for other (direct) uses
* @return boolean always true (the converted variable is returned by reference)
*/
function onespace2empty(&$item, $key=null) {
$item = $item == ' ' ? '' : $item;
return true;
}
///End DIRTY HACK
/**
* Get a number of records as an array of objects.
*
* If the query succeeds and returns at least one record, the
* return value is an array of objects, one object for each
* record found. The array key is the value from the first
* column of the result set. The object associated with that key
* has a member variable for each column of the results.
*
* @param string $table the table to query.
* @param string $field a field to check (optional).
* @param string $value the value the field must have (requred if field1 is given, else optional).
* @param string $sort an order to sort the results in (optional, a valid SQL ORDER BY parameter).
* @param string $fields a comma separated list of fields to return (optional, by default
* all fields are returned). The first field will be used as key for the
* array so must be a unique field such as 'id'.
* @param int $limitfrom return a subset of records, starting at this point (optional, required if $limitnum is set).
* @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
* @return mixed an array of objects, or false if no records were found or an error occured.
*/
function get_records($table, $field='', $value='', $sort='', $fields='*', $limitfrom='', $limitnum='') {
$rs = get_recordset($table, $field, $value, $sort, $fields, $limitfrom, $limitnum);
return recordset_to_array($rs);
}
/**
* Get a number of records as an array of objects.
*
* Return value as for @see function get_records.
*
* @param string $table the table to query.
* @param string $select A fragment of SQL to be used in a where clause in the SQL call.
* @param string $sort an order to sort the results in (optional, a valid SQL ORDER BY parameter).
* @param string $fields a comma separated list of fields to return
* (optional, by default all fields are returned). The first field will be used as key for the
* array so must be a unique field such as 'id'.
* @param int $limitfrom return a subset of records, starting at this point (optional, required if $limitnum is set).
* @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
* @return mixed an array of objects, or false if no records were found or an error occured.
*/
function get_records_select($table, $select='', $sort='', $fields='*', $limitfrom='', $limitnum='') {
$rs = get_recordset_select($table, $select, $sort, $fields, $limitfrom, $limitnum);
return recordset_to_array($rs);
}
/**
* Get a number of records as an array of objects.
*
* Return value as for @see function get_records.
*
* @param string $table The database table to be checked against.
* @param string $field The field to search
* @param string $values Comma separated list of possible value
* @param string $sort Sort order (as valid SQL sort parameter)
* @param string $fields A comma separated list of fields to be returned from the chosen table. If specified,
* the first field should be a unique one such as 'id' since it will be used as a key in the associative
* array.
* @return mixed an array of objects, or false if no records were found or an error occured.
*/
function get_records_list($table, $field='', $values='', $sort='', $fields='*', $limitfrom='', $limitnum='') {
$rs = get_recordset_list($table, $field, $values, $sort, $fields, $limitfrom, $limitnum);
return recordset_to_array($rs);
}
/**
* Get a number of records as an array of objects.
*
* Return value as for @see function get_records.
*
* @param string $sql the SQL select query to execute. The first column of this SELECT statement
* must be a unique value (usually the 'id' field), as it will be used as the key of the
* returned array.
* @param int $limitfrom return a subset of records, starting at this point (optional, required if $limitnum is set).
* @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
* @return mixed an array of objects, or false if no records were found or an error occured.
*/
function get_records_sql($sql, $limitfrom='', $limitnum='') {
$rs = get_recordset_sql($sql, $limitfrom, $limitnum);
return recordset_to_array($rs);
}
/**
* Utility function used by the following 3 methods.
*
* @param object an ADODB RecordSet object with two columns.
* @return mixed an associative array, or false if an error occured or the RecordSet was empty.
*/
function recordset_to_menu($rs) {
global $CFG;
if ($rs && $rs->RecordCount() > 0) {
$keys = array_keys($rs->fields);
$key0=$keys[0];
$key1=$keys[1];
while (!$rs->EOF) {
$menu[$rs->fields[$key0]] = $rs->fields[$key1];
$rs->MoveNext();
}
/// Really DIRTY HACK for Oracle, but it's the only way to make it work
/// until we got all those NOT NULL DEFAULT '' out from Moodle
if ($CFG->dbfamily == 'oracle') {
array_walk($menu, 'onespace2empty');
}
/// End of DIRTY HACK
return $menu;
} else {
return false;
}
}
/**
* Get the first two columns from a number of records as an associative array.
*
* Arguments as for @see function get_recordset.
*
* If no errors occur, and at least one records is found, the return value
* is an associative whose keys come from the first field of each record,
* and whose values are the corresponding second fields. If no records are found,
* or an error occurs, false is returned.
*
* @param string $table the table to query.
* @param string $field a field to check (optional).
* @param string $value the value the field must have (requred if field1 is given, else optional).
* @param string $sort an order to sort the results in (optional, a valid SQL ORDER BY parameter).
* @param string $fields a comma separated list of fields to return (optional, by default all fields are returned).
* @param int $limitfrom return a subset of records, starting at this point (optional, required if $limitnum is set).
* @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
* @return mixed an associative array, or false if no records were found or an error occured.
*/
function get_records_menu($table, $field='', $value='', $sort='', $fields='*', $limitfrom='', $limitnum='') {
$rs = get_recordset($table, $field, $value, $sort, $fields, $limitfrom, $limitnum);
return recordset_to_menu($rs);
}
/**
* Get the first two columns from a number of records as an associative array.
*
* Arguments as for @see function get_recordset_select.
* Return value as for @see function get_records_menu.
*
* @param string $table The database table to be checked against.
* @param string $select A fragment of SQL to be used in a where clause in the SQL call.
* @param string $sort Sort order (optional) - a valid SQL order parameter
* @param string $fields A comma separated list of fields to be returned from the chosen table.
* @param int $limitfrom return a subset of records, starting at this point (optional, required if $limitnum is set).
* @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
* @return mixed an associative array, or false if no records were found or an error occured.
*/
function get_records_select_menu($table, $select='', $sort='', $fields='*', $limitfrom='', $limitnum='') {
$rs = get_recordset_select($table, $select, $sort, $fields, $limitfrom, $limitnum);
return recordset_to_menu($rs);
}
/**
* Get the first two columns from a number of records as an associative array.
*
* Arguments as for @see function get_recordset_sql.
* Return value as for @see function get_records_menu.
*
* @param string $sql The SQL string you wish to be executed.
* @param int $limitfrom return a subset of records, starting at this point (optional, required if $limitnum is set).
* @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
* @return mixed an associative array, or false if no records were found or an error occured.
*/
function get_records_sql_menu($sql, $limitfrom='', $limitnum='') {
$rs = get_recordset_sql($sql, $limitfrom, $limitnum);
return recordset_to_menu($rs);
}
/**
* Get a single value from a table row where all the given fields match the given values.
*
* @param string $table the table to query.
* @param string $return the field to return the value of.
* @param string $field1 the first field to check (optional).
* @param string $value1 the value field1 must have (requred if field1 is given, else optional).
* @param string $field2 the second field to check (optional).
* @param string $value2 the value field2 must have (requred if field2 is given, else optional).
* @param string $field3 the third field to check (optional).
* @param string $value3 the value field3 must have (requred if field3 is given, else optional).
* @return mixed the specified value, or false if an error occured.
*/
function get_field($table, $return, $field1, $value1, $field2='', $value2='', $field3='', $value3='') {
global $CFG;
$select = where_clause($field1, $value1, $field2, $value2, $field3, $value3);
return get_field_sql('SELECT ' . $return . ' FROM ' . $CFG->prefix . $table . ' ' . $select);
}
/**
* Get a single value from a table row where a particular select clause is true.
*
* @uses $CFG
* @param string $table the table to query.
* @param string $return the field to return the value of.
* @param string $select A fragment of SQL to be used in a where clause in the SQL call.
* @return mixed the specified value, or false if an error occured.
*/
function get_field_select($table, $return, $select) {
global $CFG;
if ($select) {
$select = 'WHERE '. $select;
}
return get_field_sql('SELECT ' . $return . ' FROM ' . $CFG->prefix . $table . ' ' . $select);
}
/**
* Get a single value from a table.
*
* @param string $sql an SQL statement expected to return a single value.
* @return mixed the specified value, or false if an error occured.
*/
function get_field_sql($sql) {
global $CFG;
/// Strip potential LIMIT uses arriving here, debugging them (MDL-7173)
$newsql = preg_replace('/ LIMIT [0-9, ]+$/is', '', $sql);
if ($newsql != $sql) {
debugging('Incorrect use of LIMIT clause (not cross-db) in call to get_field_sql(): ' . $sql, DEBUG_DEVELOPER);
$sql = $newsql;
}
$rs = get_recordset_sql($sql, 0, 1);
if ($rs && $rs->RecordCount() == 1) {
/// DIRTY HACK to retrieve all the ' ' (1 space) fields converted back
/// to '' (empty string) for Oracle. It's the only way to work with
/// all those NOT NULL DEFAULT '' fields until we definetively delete them
if ($CFG->dbfamily == 'oracle') {
$value = reset($rs->fields);
onespace2empty($value);
return $value;
}
/// End of DIRTY HACK
return reset($rs->fields);
} else {
return false;
}
}
/**
* Get an array of data from one or more fields from a database
* use to get a column, or a series of distinct values
*
* @uses $CFG
* @uses $db
* @param string $sql The SQL string you wish to be executed.
* @return mixed|false Returns the value return from the SQL statment or false if an error occured.
* @todo Finish documenting this function
*/
function get_fieldset_sql($sql) {
global $db, $CFG;
if (defined('MDL_PERFDB')) { global $PERF ; $PERF->dbqueries++; };
$rs = $db->Execute($sql);
if (!$rs) {
debugging($db->ErrorMsg() .'<br /><br />'. $sql);
if (!empty($CFG->dblogerror)) {
$debug=array_shift(debug_backtrace());
error_log("SQL ".$db->ErrorMsg()." in {$debug['file']} on line {$debug['line']}. STATEMENT: $sql");
}
return false;
}
if ( $rs->RecordCount() > 0 ) {
$keys = array_keys($rs->fields);
$key0 = $keys[0];
$results = array();
while (!$rs->EOF) {
array_push($results, $rs->fields[$key0]);
$rs->MoveNext();
}
/// DIRTY HACK to retrieve all the ' ' (1 space) fields converted back
/// to '' (empty string) for Oracle. It's the only way to work with
/// all those NOT NULL DEFAULT '' fields until we definetively delete them
if ($CFG->dbfamily == 'oracle') {
array_walk($results, 'onespace2empty');
}
/// End of DIRTY HACK
return $results;
} else {
return false;
}
}
/**
* Set a single field in every table row where all the given fields match the given values.
*
* @uses $CFG
* @uses $db
* @param string $table The database table to be checked against.
* @param string $newfield the field to set.
* @param string $newvalue the value to set the field to.
* @param string $field1 the first field to check (optional).
* @param string $value1 the value field1 must have (requred if field1 is given, else optional).
* @param string $field2 the second field to check (optional).
* @param string $value2 the value field2 must have (requred if field2 is given, else optional).
* @param string $field3 the third field to check (optional).
* @param string $value3 the value field3 must have (requred if field3 is given, else optional).
* @return mixed An ADODB RecordSet object with the results from the SQL call or false.
*/
function set_field($table, $newfield, $newvalue, $field1, $value1, $field2='', $value2='', $field3='', $value3='') {
global $CFG;
// Clear record_cache based on the parameters passed
// (individual record or whole table)
if (!empty($CFG->rcache)) {
if ($field1 == 'id') {
rcache_unset($table, $value1);
} else if ($field2 == 'id') {
rcache_unset($table, $value1);
} else if ($field3 == 'id') {
rcache_unset($table, $value1);
} else {
rcache_unset_table($table);
}
}
$select = where_clause($field1, $value1, $field2, $value2, $field3, $value3);
return set_field_select($table, $newfield, $newvalue, $select, true);
}
/**
* Set a single field in every table row where the select statement evaluates to true.
*
* @uses $CFG
* @uses $db
* @param string $table The database table to be checked against.
* @param string $newfield the field to set.
* @param string $newvalue the value to set the field to.
* @param string $select a fragment of SQL to be used in a where clause in the SQL call.
* @param boolean $localcall Leave this set to false. (Should only be set to true by set_field.)
* @return mixed An ADODB RecordSet object with the results from the SQL call or false.
*/
function set_field_select($table, $newfield, $newvalue, $select, $localcall = false) {
global $db, $CFG;
if (defined('MDL_PERFDB')) { global $PERF ; $PERF->dbqueries++; };
if (!$localcall) {
if ($select) {
$select = 'WHERE ' . $select;
}
// Clear record_cache based on the parameters passed
// (individual record or whole table)
if (!empty($CFG->rcache)) {
rcache_unset_table($table);
}
}
$dataobject = new StdClass;
$dataobject->{$newfield} = $newvalue;
// Oracle DIRTY HACK -
if ($CFG->dbfamily == 'oracle') {
oracle_dirty_hack($table, $dataobject); // Convert object to the correct "empty" values for Oracle DB
$newvalue = $dataobject->{$newfield};
}
// End DIRTY HACK
/// Under Oracle and MSSQL we have our own set field process
/// If the field being updated is clob/blob, we use our alternate update here
/// They will be updated later
if (($CFG->dbfamily == 'oracle' || $CFG->dbfamily == 'mssql') && !empty($select)) {
/// Detect lobs
$foundclobs = array();
$foundblobs = array();
db_detect_lobs($table, $dataobject, $foundclobs, $foundblobs);
}
/// Under Oracle and MSSQL, finally, Update all the Clobs and Blobs present in the record
/// if we know we have some of them in the query
if (($CFG->dbfamily == 'oracle' || $CFG->dbfamily == 'mssql') && !empty($select) &&
(!empty($foundclobs) || !empty($foundblobs))) {
if (!db_update_lobs($table, $select, $foundclobs, $foundblobs)) {
return false; //Some error happened while updating LOBs
} else {
return true; //Everrything was ok
}
}
/// Arriving here, standard update
return $db->Execute('UPDATE '. $CFG->prefix . $table .' SET '. $newfield .' = \''. $newvalue .'\' '. $select);
}
/**
* Delete the records from a table where all the given fields match the given values.
*
* @uses $CFG
* @uses $db
* @param string $table the table to delete from.
* @param string $field1 the first field to check (optional).
* @param string $value1 the value field1 must have (requred if field1 is given, else optional).
* @param string $field2 the second field to check (optional).
* @param string $value2 the value field2 must have (requred if field2 is given, else optional).
* @param string $field3 the third field to check (optional).
* @param string $value3 the value field3 must have (requred if field3 is given, else optional).
* @return mixed An ADODB RecordSet object with the results from the SQL call or false.
*/
function delete_records($table, $field1='', $value1='', $field2='', $value2='', $field3='', $value3='') {
global $db, $CFG;
// Clear record_cache based on the parameters passed
// (individual record or whole table)
if (!empty($CFG->rcache)) {
if ($field1 == 'id') {
rcache_unset($table, $value1);
} else if ($field2 == 'id') {
rcache_unset($table, $value2);
} else if ($field3 == 'id') {
rcache_unset($table, $value3);
} else {
rcache_unset_table($table);
}
}
if (defined('MDL_PERFDB')) { global $PERF ; $PERF->dbqueries++; };
$select = where_clause($field1, $value1, $field2, $value2, $field3, $value3);
return $db->Execute('DELETE FROM '. $CFG->prefix . $table .' '. $select);
}
/**
* Delete one or more records from a table
*
* @uses $CFG
* @uses $db
* @param string $table The database table to be checked against.
* @param string $select A fragment of SQL to be used in a where clause in the SQL call (used to define the selection criteria).
* @return object A PHP standard object with the results from the SQL call.
* @todo Verify return type.
*/
function delete_records_select($table, $select='') {
global $CFG, $db;
// Clear record_cache (whole table)
if (!empty($CFG->rcache)) {
rcache_unset_table($table);
}
if (defined('MDL_PERFDB')) { global $PERF ; $PERF->dbqueries++; };
if ($select) {
$select = 'WHERE '.$select;
}
return $db->Execute('DELETE FROM '. $CFG->prefix . $table .' '. $select);
}
/**
* Insert a record into a table and return the "id" field if required
*
* If the return ID isn't required, then this just reports success as true/false.
* $dataobject is an object containing needed data
*
* @uses $db
* @uses $CFG
* @param string $table The database table to be checked against.
* @param array $dataobject A data object with values for one or more fields in the record
* @param bool $returnid Should the id of the newly created record entry be returned? If this option is not requested then true/false is returned.
* @param string $primarykey The primary key of the table we are inserting into (almost always "id")
*/
function insert_record($table, $dataobject, $returnid=true, $primarykey='id') {
global $db, $CFG, $empty_rs_cache;
if (empty($db)) {
return false;
}
/// Temporary hack as part of phasing out all access to obsolete user tables XXX
if (!empty($CFG->rolesactive)) {
if (in_array($table, array('user_students', 'user_teachers', 'user_coursecreators', 'user_admins'))) {
if (debugging()) { var_dump(debug_backtrace()); }
error('This SQL relies on obsolete tables ('.$table.')! Your code must be fixed by a developer.');
}
}
if (defined('MDL_PERFDB')) { global $PERF ; $PERF->dbqueries++; };
/// In Moodle we always use auto-numbering fields for the primary key
/// so let's unset it now before it causes any trouble later
unset($dataobject->{$primarykey});
/// Get an empty recordset. Cache for multiple inserts.
if (empty($empty_rs_cache[$table])) {
/// Execute a dummy query to get an empty recordset
if (!$empty_rs_cache[$table] = $db->Execute('SELECT * FROM '. $CFG->prefix . $table .' WHERE '. $primarykey .' = \'-1\'')) {
return false;
}
}
$rs = $empty_rs_cache[$table];
/// Postgres doesn't have the concept of primary key built in
/// and will return the OID which isn't what we want.
/// The efficient and transaction-safe strategy is to
/// move the sequence forward first, and make the insert
/// with an explicit id.
if ( $CFG->dbfamily === 'postgres' && $returnid == true ) {
if ($nextval = (int)get_field_sql("SELECT NEXTVAL('{$CFG->prefix}{$table}_{$primarykey}_seq')")) {
$dataobject->{$primarykey} = $nextval;
}
}
/// Begin DIRTY HACK
if ($CFG->dbfamily == 'oracle') {
oracle_dirty_hack($table, $dataobject); // Convert object to the correct "empty" values for Oracle DB
}
/// End DIRTY HACK
/// Under Oracle and MSSQL we have our own insert record process
/// detect all the clob/blob fields and change their contents to @#CLOB#@ and @#BLOB#@
/// saving them into $foundclobs and $foundblobs [$fieldname]->contents
/// Same for mssql (only processing blobs - image fields)
if ($CFG->dbfamily == 'oracle' || $CFG->dbfamily == 'mssql') {
$foundclobs = array();
$foundblobs = array();
db_detect_lobs($table, $dataobject, $foundclobs, $foundblobs);
}
/// Under Oracle, if the primary key inserted has been requested OR
/// if there are LOBs to insert, we calculate the next value via
/// explicit query to the sequence.
/// Else, the pre-insert trigger will do the job, because the primary
/// key isn't needed at all by the rest of PHP code
if ($CFG->dbfamily === 'oracle' && ($returnid == true || !empty($foundclobs) || !empty($foundblobs))) {
/// We need this here (move this function to dmlib?)
include_once($CFG->libdir . '/ddllib.php');
$xmldb_table = new XMLDBTable($table);
$seqname = find_sequence_name($xmldb_table);
if (!$seqname) {
/// Fallback, seqname not found, something is wrong. Inform and use the alternative getNameForObject() method
debugging('Sequence name for table ' . $table->getName() . ' not found', DEBUG_DEVELOPER);
$generator = new XMLDBoci8po();
$generator->setPrefix($CFG->prefix);
$seqname = $generator->getNameForObject($table, $primarykey, 'seq');
}
if ($nextval = (int)$db->GenID($seqname)) {
$dataobject->{$primarykey} = $nextval;
}
}
/// Get the correct SQL from adoDB
if (!$insertSQL = $db->GetInsertSQL($rs, (array)$dataobject, true)) {
return false;
}
/// Under Oracle and MSSQL, replace all the '@#CLOB#@' and '@#BLOB#@' ocurrences to proper default values
/// if we know we have some of them in the query
if (($CFG->dbfamily == 'oracle' || $CFG->dbfamily == 'mssql') &&
(!empty($foundclobs) || !empty($foundblobs))) {
/// Initial configuration, based on DB
switch ($CFG->dbfamily) {
case 'oracle':
$clobdefault = 'empty_clob()'; //Value of empty default clobs for this DB
$blobdefault = 'empty_blob()'; //Value of empty default blobs for this DB
break;
case 'mssql':
$clobdefault = 'null'; //Value of empty default clobs for this DB (under mssql this won't be executed
$blobdefault = 'null'; //Value of empty default blobs for this DB
break;
}
$insertSQL = str_replace("'@#CLOB#@'", $clobdefault, $insertSQL);
$insertSQL = str_replace("'@#BLOB#@'", $blobdefault, $insertSQL);
}
/// Run the SQL statement
if (!$rs = $db->Execute($insertSQL)) {
debugging($db->ErrorMsg() .'<br /><br />'.$insertSQL);
if (!empty($CFG->dblogerror)) {
$debug=array_shift(debug_backtrace());
error_log("SQL ".$db->ErrorMsg()." in {$debug['file']} on line {$debug['line']}. STATEMENT: $insertSQL");
}
return false;
}
/// Under Oracle, finally, Update all the Clobs and Blobs present in the record
/// if we know we have some of them in the query
if ($CFG->dbfamily == 'oracle' &&
!empty($dataobject->{$primarykey}) &&
(!empty($foundclobs) || !empty($foundblobs))) {
if (!db_update_lobs($table, $dataobject->{$primarykey}, $foundclobs, $foundblobs)) {
return false; //Some error happened while updating LOBs
}
}
/// If a return ID is not needed then just return true now (but not in MSSQL DBs, where we may have some pending tasks)
if (!$returnid && $CFG->dbfamily != 'mssql') {
return true;
}
/// We already know the record PK if it's been passed explicitly,
/// or if we've retrieved it from a sequence (Postgres and Oracle).
if (!empty($dataobject->{$primarykey})) {
return $dataobject->{$primarykey};
}
/// This only gets triggered with MySQL and MSQL databases
/// however we have some postgres fallback in case we failed
/// to find the sequence.
$id = $db->Insert_ID();
/// Under MSSQL all the Clobs and Blobs (IMAGE) present in the record
/// if we know we have some of them in the query
if (($CFG->dbfamily == 'mssql') &&
!empty($id) &&
(!empty($foundclobs) || !empty($foundblobs))) {
if (!db_update_lobs($table, $id, $foundclobs, $foundblobs)) {
return false; //Some error happened while updating LOBs
}
}
if ($CFG->dbfamily === 'postgres') {
// try to get the primary key based on id
if ( ($rs = $db->Execute('SELECT '. $primarykey .' FROM '. $CFG->prefix . $table .' WHERE oid = '. $id))
&& ($rs->RecordCount() == 1) ) {
trigger_error("Retrieved $primarykey from oid on table $table because we could not find the sequence.");
return (integer)reset($rs->fields);
}
trigger_error('Failed to retrieve primary key after insert: SELECT '. $primarykey .
' FROM '. $CFG->prefix . $table .' WHERE oid = '. $id);
return false;
}
return (integer)$id;
}
/**
* Update a record in a table
*
* $dataobject is an object containing needed data
* Relies on $dataobject having a variable "id" to
* specify the record to update
*
* @uses $CFG
* @uses $db
* @param string $table The database table to be checked against.
* @param array $dataobject An object with contents equal to fieldname=>fieldvalue. Must have an entry for 'id' to map to the table specified.
* @return bool
*/
function update_record($table, $dataobject) {
global $db, $CFG;
if (! isset($dataobject->id) ) {
return false;
}
// Remove this record from record cache since it will change
if (!empty($CFG->rcache)) {
rcache_unset($table, $dataobject->id);
}
/// Temporary hack as part of phasing out all access to obsolete user tables XXX
if (!empty($CFG->rolesactive)) {
if (in_array($table, array('user_students', 'user_teachers', 'user_coursecreators', 'user_admins'))) {
if (debugging()) { var_dump(debug_backtrace()); }
error('This SQL relies on obsolete tables ('.$table.')! Your code must be fixed by a developer.');
}
}
/// Begin DIRTY HACK
if ($CFG->dbfamily == 'oracle') {
oracle_dirty_hack($table, $dataobject); // Convert object to the correct "empty" values for Oracle DB
}
/// End DIRTY HACK
/// Under Oracle and MSSQL we have our own update record process
/// detect all the clob/blob fields and delete them from the record being updated
/// saving them into $foundclobs and $foundblobs [$fieldname]->contents
/// They will be updated later
if (($CFG->dbfamily == 'oracle' || $CFG->dbfamily == 'mssql')
&& !empty($dataobject->id)) {
/// Detect lobs
$foundclobs = array();
$foundblobs = array();
db_detect_lobs($table, $dataobject, $foundclobs, $foundblobs, true);
}
// Determine all the fields in the table
if (!$columns = $db->MetaColumns($CFG->prefix . $table)) {
return false;
}
$data = (array)$dataobject;
if (defined('MDL_PERFDB')) { global $PERF ; $PERF->dbqueries++; };
// Pull out data matching these fields
$ddd = array();
foreach ($columns as $column) {
if ($column->name <> 'id' and isset($data[$column->name]) ) {
$ddd[$column->name] = $data[$column->name];
// PostgreSQL bytea support
if ($CFG->dbfamily == 'postgres' && $column->type == 'bytea') {
$ddd[$column->name] = $db->BlobEncode($ddd[$column->name]);
}
}
}
// Construct SQL queries
$numddd = count($ddd);
$count = 0;
$update = '';
/// Only if we have fields to be updated (this will prevent both wrong updates +
/// updates of only LOBs in Oracle
if ($numddd) {
foreach ($ddd as $key => $value) {
$count++;
$update .= $key .' = \''. $value .'\''; // All incoming data is already quoted
if ($count < $numddd) {
$update .= ', ';
}
}
if (!$rs = $db->Execute('UPDATE '. $CFG->prefix . $table .' SET '. $update .' WHERE id = \''. $dataobject->id .'\'')) {
debugging($db->ErrorMsg() .'<br /><br />UPDATE '. $CFG->prefix . $table .' SET '. $update .' WHERE id = \''. $dataobject->id .'\'');
if (!empty($CFG->dblogerror)) {
$debug=array_shift(debug_backtrace());
error_log("SQL ".$db->ErrorMsg()." in {$debug['file']} on line {$debug['line']}. STATEMENT: UPDATE $CFG->prefix$table SET $update WHERE id = '$dataobject->id'");
}
return false;
}
}
/// Under Oracle AND MSSQL, finally, Update all the Clobs and Blobs present in the record
/// if we know we have some of them in the query
if (($CFG->dbfamily == 'oracle' || $CFG->dbfamily == 'mssql') &&
!empty($dataobject->id) &&
(!empty($foundclobs) || !empty($foundblobs))) {
if (!db_update_lobs($table, $dataobject->id, $foundclobs, $foundblobs)) {
return false; //Some error happened while updating LOBs
}
}
return true;
}
/**
* Returns the proper SQL to do paging
*
* @uses $CFG
* @param string $page Offset page number
* @param string $recordsperpage Number of records per page
* @deprecated Moodle 1.7 use the new $limitfrom, $limitnum available in all
* the get_recordXXX() funcions.
* @return string
*/
function sql_paging_limit($page, $recordsperpage) {
global $CFG;
debugging('Function sql_paging_limit() is deprecated. Replace it with the correct use of limitfrom, limitnum parameters', DEBUG_DEVELOPER);
switch ($CFG->dbfamily) {
case 'postgres':
return 'LIMIT '. $recordsperpage .' OFFSET '. $page;
default:
return 'LIMIT '. $page .','. $recordsperpage;
}
}
/**
* Returns the proper SQL to do LIKE in a case-insensitive way
*
* Note the LIKE are case sensitive for Oracle. Oracle 10g is required to use
* the caseinsensitive search using regexp_like() or NLS_COMP=LINGUISTIC :-(
* See http://docs.moodle.org/en/XMLDB_Problems#Case-insensitive_searches
*
* @uses $CFG
* @return string
*/
function sql_ilike() {
global $CFG;
switch ($CFG->dbfamily) {
case 'postgres':
return 'ILIKE';
default:
return 'LIKE';
}
}
/**
* Returns the proper SQL (for the dbms in use) to concatenate $firstname and $lastname
*
* @uses $CFG
* @param string $firstname User's first name
* @param string $lastname User's last name
* @return string
*/
function sql_fullname($firstname='firstname', $lastname='lastname') {
return sql_concat($firstname, "' '", $lastname);
}
/**
* Returns the proper SQL to do CONCAT between the elements passed
* Can take many parameters - just a passthrough to $db->Concat()
*
* @uses $db
* @param string $element
* @return string
*/
function sql_concat() {
global $db;
$args = func_get_args();
return call_user_func_array(array($db, 'Concat'), $args);
}
/**
* Returns the proper SQL to do CONCAT between the elements passed
* with a given separator
*
* @uses $db
* @param string $separator
* @param array $elements
* @return string
*/
function sql_concat_join($separator="' '", $elements=array()) {
global $db;
// copy to ensure pass by value
$elem = $elements;
// Intersperse $elements in the array.
// Add items to the array on the fly, walking it
// _backwards_ splicing the elements in. The loop definition
// should skip first and last positions.
for ($n=count($elem)-1; $n > 0 ; $n--) {
array_splice($elem, $n, 0, $separator);
}
return call_user_func_array(array($db, 'Concat'), $elem);
}
/**
* Returns the proper SQL to do IS NULL
* @uses $CFG
* @param string $fieldname The field to add IS NULL to
* @return string
*/
function sql_isnull($fieldname) {
global $CFG;
switch ($CFG->dbfamily) {
case 'mysql':
return $fieldname.' IS NULL';
default:
return $fieldname.' IS NULL';
}
}
/**
* Returns the proper AS keyword to be used to aliase columns
* SQL defines the keyword as optional and nobody but PG
* seems to require it. This function should be used inside all
* the statements using column aliases.
* Note than the use of table aliases doesn't require the
* AS keyword at all, only columns for postgres.
* @uses $CFG
* @ return string the keyword
* @deprecated Moodle 1.7 because coding guidelines now enforce to use AS in column aliases
*/
function sql_as() {
global $CFG, $db;
switch ($CFG->dbfamily) {
case 'postgres':
return 'AS';
default:
return '';
}
}
/**
* Returns the proper substr() function for each DB
* Relies on ADOdb $db->substr property
*/
function sql_substr() {
global $db;
return $db->substr;
}
/**
* Returns the SQL text to be used to order by one TEXT (clob) column, because
* some RDBMS doesn't support direct ordering of such fields.
* Note that the use or queries being ordered by TEXT columns must be minimised,
* because it's really slooooooow.
* @param string fieldname the name of the TEXT field we need to order by
* @param string number of chars to use for the ordering (defaults to 32)
* @return string the piece of SQL code to be used in your statement.
*/
function sql_order_by_text($fieldname, $numchars=32) {
global $CFG;
switch ($CFG->dbfamily) {
case 'mssql':
return 'CONVERT(varchar, ' . $fieldname . ', ' . $numchars . ')';
break;
case 'oracle':
return 'dbms_lob.substr(' . $fieldname . ', ' . $numchars . ',1)';
break;
default:
return $fieldname;
}
}
/**
* Returns SQL to be used as a subselect to find the primary role of users.
* Geoff Cant <geoff@catalyst.net.nz> (the author) is very keen for this to
* be implemented as a view in future versions.
*
* eg if this function returns a string called $primaryroles, then you could:
* $sql = 'SELECT COUNT(DISTINCT prs.userid) FROM ('.$primary_roles.') prs
* WHERE prs.primary_roleid='.$role->id.' AND prs.courseid='.$course->id.
* ' AND prs.contextlevel = '.CONTEXT_COURSE;
*
* @return string the piece of SQL code to be used in your FROM( ) statement.
*/
function sql_primary_role_subselect() {
global $CFG;
return 'SELECT ra.userid,
ra.roleid AS primary_roleid,
ra.contextid,
r.sortorder,
r.name,
r.description,
r.shortname,
c.instanceid AS courseid,
c.contextlevel
FROM '.$CFG->prefix.'role_assignments ra
INNER JOIN '.$CFG->prefix.'role r ON ra.roleid = r.id
INNER JOIN '.$CFG->prefix.'context c ON ra.contextid = c.id
WHERE NOT EXISTS (
SELECT 1
FROM '.$CFG->prefix.'role_assignments i_ra
INNER JOIN '.$CFG->prefix.'role i_r ON i_ra.roleid = i_r.id
WHERE ra.userid = i_ra.userid AND
ra.contextid = i_ra.contextid AND
i_r.sortorder < r.sortorder
) ';
}
/**
* Prepare a SQL WHERE clause to select records where the given fields match the given values.
*
* Prepares a where clause of the form
* WHERE field1 = value1 AND field2 = value2 AND field3 = value3
* except that you need only specify as many arguments (zero to three) as you need.
*
* @param string $field1 the first field to check (optional).
* @param string $value1 the value field1 must have (requred if field1 is given, else optional).
* @param string $field2 the second field to check (optional).
* @param string $value2 the value field2 must have (requred if field2 is given, else optional).
* @param string $field3 the third field to check (optional).
* @param string $value3 the value field3 must have (requred if field3 is given, else optional).
*/
function where_clause($field1='', $value1='', $field2='', $value2='', $field3='', $value3='') {
if ($field1) {
$select = "WHERE $field1 = '$value1'";
if ($field2) {
$select .= " AND $field2 = '$value2'";
if ($field3) {
$select .= " AND $field3 = '$value3'";
}
}
} else {
$select = '';
}
return $select;
}
/**
* Get the data type of a table column, using an ADOdb MetaType() call.
*
* @uses $CFG
* @uses $db
* @param string $table The name of the database table
* @param string $column The name of the field in the table
* @return string Field type or false if error
*/
function column_type($table, $column) {
global $CFG, $db;
if (defined('MDL_PERFDB')) { global $PERF ; $PERF->dbqueries++; };
if(!$rs = $db->Execute('SELECT '.$column.' FROM '.$CFG->prefix.$table.' WHERE 1=2')) {
return false;
}
$field = $rs->FetchField(0);
return $rs->MetaType($field->type);
}
/**
* This function will execute an array of SQL commands, returning
* true/false if any error is found and stopping/continue as desired.
* It's widely used by all the ddllib.php functions
*
* @param array sqlarr array of sql statements to execute
* @param boolean continue to specify if must continue on error (true) or stop (false)
* @param boolean feedback to specify to show status info (true) or not (false)
* @param boolean true if everything was ok, false if some error was found
*/
function execute_sql_arr($sqlarr, $continue=true, $feedback=true) {
if (!is_array($sqlarr)) {
return false;
}
$status = true;
foreach($sqlarr as $sql) {
if (!execute_sql($sql, $feedback)) {
$status = false;
if (!$continue) {
break;
}
}
}
return $status;
}
/**
* This internal function, called from setup.php, sets all the configuration
* needed to work properly against any DB. It setups connection encoding
* and some other variables. Also, ir defines the $CFG->dbfamily variable
* to handle conditional code better than using $CFG->dbtype directly.
*
* This function must contain the init code needed for each dbtype supported.
*/
function configure_dbconnection() {
global $CFG, $db;
switch ($CFG->dbtype) {
case 'mysql':
case 'mysqli':
$db->Execute("SET NAMES 'utf8'");
break;
case 'postgres7':
$db->Execute("SET NAMES 'utf8'");
break;
case 'mssql':
case 'mssql_n':
case 'odbc_mssql':
/// No need to set charset. It must be specified in the driver conf
/// Allow quoted identifiers
$db->Execute('SET QUOTED_IDENTIFIER ON');
/// Force ANSI nulls so the NULL check was done by IS NULL and NOT IS NULL
/// instead of equal(=) and distinct(<>) simbols
$db->Execute('SET ANSI_NULLS ON');
/// Enable sybase quotes, so addslashes and stripslashes will use "'"
ini_set('magic_quotes_sybase', '1');
/// NOTE: Not 100% useful because GPC has been addslashed with the setting off
/// so IT'S MANDATORY TO CHANGE THIS UNDER php.ini or .htaccess for this DB
/// or to turn off magic_quotes to allow Moodle to do it properly
break;
case 'oci8po':
/// No need to set charset. It must be specified by the NLS_LANG env. variable
/// Enable sybase quotes, so addslashes and stripslashes will use "'"
ini_set('magic_quotes_sybase', '1');
/// NOTE: Not 100% useful because GPC has been addslashed with the setting off
/// so IT'S MANDATORY TO ENABLE THIS UNDER php.ini or .htaccess for this DB
/// or to turn off magic_quotes to allow Moodle to do it properly
break;
}
/// Finally define dbfamily
set_dbfamily();
}
/**
* This internal function sets and returns the proper value for $CFG->dbfamily based on $CFG->dbtype
* It's called by configure_dbconnection() and at install time. Shouldn't be used
* in other places. Code should rely on dbfamily to perform conditional execution
* instead of using dbtype directly. This allows quicker adoption of different
* drivers going against the same DB backend.
*
* This function must contain the init code needed for each dbtype supported.
*
* return string dbfamily value (mysql, postgres, oracle, mssql)
*/
function set_dbfamily() {
global $CFG, $INSTALL;
// Since this function is also used during installation process, i.e. during install.php before $CFG->dbtype is set.
// we need to get dbtype from the right variable
if (!empty($INSTALL['dbtype'])) {
$dbtype = $INSTALL['dbtype'];
} else {
$dbtype = $CFG->dbtype;
}
switch ($dbtype) {
case 'mysql':
case 'mysqli':
$CFG->dbfamily='mysql';
break;
case 'postgres7':
$CFG->dbfamily='postgres';
break;
case 'mssql':
case 'mssql_n':
case 'odbc_mssql':
$CFG->dbfamily='mssql';
break;
case 'oci8po':
$CFG->dbfamily='oracle';
break;
}
return $CFG->dbfamily;
}
/**
* This function will handle all the records before being inserted/updated to DB for Oracle
* installations. This is because the "special feature" of Oracle where the empty string is
* equal to NULL and this presents a problem with all our currently NOT NULL default '' fields.
*
* Once Moodle DB will be free of this sort of false NOT NULLS, this hack could be removed safely
*
* Note that this function is 100% private and should be used, exclusively by DML functions
* in this file. Also, this is considered a DIRTY HACK to be removed when possible. (stronk7)
*
* This function is private and must not be used outside dmllib at all
*
* @param $table string the table where the record is going to be inserted/updated (without prefix)
* @param $dataobject object the object to be inserted/updated
* @param $usecache boolean flag to determinate if we must use the per request cache of metadata
* true to use it, false to ignore and delete it
*/
function oracle_dirty_hack ($table, &$dataobject, $usecache = true) {
global $CFG, $db, $metadata_cache;
/// Init and delete metadata cache
if (!isset($metadata_cache) || !$usecache) {
$metadata_cache = array();
}
/// For Oracle DB, empty strings are converted to NULLs in DB
/// and this breaks a lot of NOT NULL columns currenty Moodle. In the future it's
/// planned to move some of them to NULL, if they must accept empty values and this
/// piece of code will become less and less used. But, for now, we need it.
/// What we are going to do is to examine all the data being inserted and if it's
/// an empty string (NULL for Oracle) and the field is defined as NOT NULL, we'll modify
/// such data in the best form possible ("0" for booleans and numbers and " " for the
/// rest of strings. It isn't optimal, but the only way to do so.
/// In the oppsite, when retrieving records from Oracle, we'll decode " " back to
/// empty strings to allow everything to work properly. DIRTY HACK.
/// If the db isn't Oracle, return without modif
if ( $CFG->dbfamily != 'oracle') {
return;
}
/// Get Meta info to know what to change, using the cached meta if exists
if (!isset($metadata_cache[$table])) {
$metadata_cache[$table] = array_change_key_case($db->MetaColumns($CFG->prefix . $table), CASE_LOWER);
}
$columns = $metadata_cache[$table];
/// Iterate over all the fields in the insert, transforming values
/// in the best possible form
foreach ($dataobject as $fieldname => $fieldvalue) {
/// If the field doesn't exist in metadata, skip
if (!isset($columns[strtolower($fieldname)])) {
continue;
}
/// If the field ins't VARCHAR or CLOB, skip
if ($columns[strtolower($fieldname)]->type != 'VARCHAR2' && $columns[strtolower($fieldname)]->type != 'CLOB') {
continue;
}
/// If the field isn't NOT NULL, skip (it's nullable, so accept empty values)
if (!$columns[strtolower($fieldname)]->not_null) {
continue;
}
/// If the value isn't empty, skip
if (!empty($fieldvalue)) {
continue;
}
/// Now, we have one empty value, going to be inserted to one NOT NULL, VARCHAR2 or CLOB field
/// Try to get the best value to be inserted
if (gettype($fieldvalue) == 'boolean') {
$dataobject->$fieldname = '0'; /// Transform false to '0' that evaluates the same for PHP
} else if (gettype($fieldvalue) == 'integer') {
$dataobject->$fieldname = '0'; /// Transform 0 to '0' that evaluates the same for PHP
} else if (gettype($fieldvalue) == 'NULL') {
$dataobject->$fieldname = '0'; /// Transform NULL to '0' that evaluates the same for PHP
} else {
$dataobject->$fieldname = ' '; /// Transform '' to ' ' that DONT'T EVALUATE THE SAME
/// (we'll transform back again on get_records_XXX functions and others)!!
}
}
}
/// End of DIRTY HACK
/**
* This function will search for all the CLOBs and BLOBs fields passed in the dataobject, replacing
* their contents by the fixed strings '@#CLOB#@' and '@#BLOB#@' and returning one array for all the
* found CLOBS and another for all the found BLOBS
* Used by Oracle drivers to perform the two-step insertion/update of LOBs and
* by MSSQL to perform the same exclusively for BLOBs (IMAGE fields)
*
* This function is private and must not be used outside dmllib at all
*
* @param $table string the table where the record is going to be inserted/updated (without prefix)
* @param $dataobject object the object to be inserted/updated
* @param $clobs array of clobs detected
* @param $dataobject array of blobs detected
* @param $unset boolean to specify if we must unset found LOBs from the original object (true) or
* just return them modified to @#CLOB#@ and @#BLOB#@ (false)
* @param $usecache boolean flag to determinate if we must use the per request cache of metadata
* true to use it, false to ignore and delete it
*/
function db_detect_lobs ($table, &$dataobject, &$clobs, &$blobs, $unset = false, $usecache = true) {
global $CFG, $db, $metadata_cache;
$dataarray = (array)$dataobject; //Convert to array. It's supposed that PHP 4.3 doesn't iterate over objects
/// Initial configuration, based on DB
switch ($CFG->dbfamily) {
case 'oracle':
$clobdbtype = 'CLOB'; //Name of clobs for this DB
$blobdbtype = 'BLOB'; //Name of blobs for this DB
break;
case 'mssql':
$clobdbtype = 'NOTPROCESSES'; //Name of clobs for this DB (under mssql flavours we don't process CLOBS)
$blobdbtype = 'IMAGE'; //Name of blobs for this DB
break;
default:
return; //Other DB doesn't need this two step to happen, prevent continue
}
/// Init and delete metadata cache
if (!isset($metadata_cache) || !$usecache) {
$metadata_cache = array();
}
/// Get Meta info to know what to change, using the cached meta if exists
if (!isset($metadata_cache[$table])) {
$metadata_cache[$table] = array_change_key_case($db->MetaColumns($CFG->prefix . $table), CASE_LOWER);
}
$columns = $metadata_cache[$table];
foreach ($dataarray as $fieldname => $fieldvalue) {
/// If the field doesn't exist in metadata, skip
if (!isset($columns[strtolower($fieldname)])) {
continue;
}
/// If the field is CLOB, update its value to '@#CLOB#@' and store it in the $clobs array
if (strtoupper($columns[strtolower($fieldname)]->type) == $clobdbtype) {
/// Oracle optimization. CLOBs under 4000cc can be directly inserted (no need to apply 2-phases to them)
if ($CFG->dbfamily = 'oracle' && strlen($dataobject->$fieldname) < 4000) {
continue;
}
$clobs[$fieldname] = $dataobject->$fieldname;
if ($unset) {
unset($dataobject->$fieldname);
} else {
$dataobject->$fieldname = '@#CLOB#@';
}
continue;
}
/// If the field is BLOB OR IMAGE, update its value to '@#BLOB#@' and store it in the $blobs array
if (strtoupper($columns[strtolower($fieldname)]->type) == $blobdbtype) {
$blobs[$fieldname] = $dataobject->$fieldname;
if ($unset) {
unset($dataobject->$fieldname);
} else {
$dataobject->$fieldname = '@#BLOB#@';
}
continue;
}
}
}
/**
* This function will iterate over $clobs and $blobs array, executing the needed
* UpdateClob() and UpdateBlob() ADOdb function calls to store LOBs contents properly
* Records to be updated are always searched by PK (id always!)
*
* Used by Orace CLOBS and BLOBS and MSSQL IMAGES
*
* This function is private and must not be used outside dmllib at all
*
* @param $table string the table where the record is going to be inserted/updated (without prefix)
* @param $sqlcondition mixed value defining the records to be LOB-updated. It it's a number, must point
* to the PK og the table (id field), else it's processed as one harcoded SQL condition (WHERE clause)
* @param $clobs array of clobs to be updated
* @param $blobs array of blobs to be updated
*/
function db_update_lobs ($table, $sqlcondition, &$clobs, &$blobs) {
global $CFG, $db;
$status = true;
/// Initial configuration, based on DB
switch ($CFG->dbfamily) {
case 'oracle':
$clobdbtype = 'CLOB'; //Name of clobs for this DB
$blobdbtype = 'BLOB'; //Name of blobs for this DB
break;
case 'mssql':
$clobdbtype = 'NOTPROCESSES'; //Name of clobs for this DB (under mssql flavours we don't process CLOBS)
$blobdbtype = 'IMAGE'; //Name of blobs for this DB
break;
default:
return; //Other DB doesn't need this two step to happen, prevent continue
}
/// Calculate the update sql condition
if (is_numeric($sqlcondition)) { /// If passing a number, it's the PK of the table (id)
$sqlcondition = 'id=' . $sqlcondition;
} else { /// Else, it's a formal standard SQL condition, we try to delete the WHERE in case it exists
$sqlcondition = trim(preg_replace('/^WHERE/is', '', trim($sqlcondition)));
}
/// Update all the clobs
if ($clobs) {
foreach ($clobs as $key => $value) {
if (defined('MDL_PERFDB')) { global $PERF ; $PERF->dbqueries++; }; /// Count the extra updates in PERF
if (!$db->UpdateClob($CFG->prefix.$table, $key, $value, $sqlcondition)) {
$status = false;
$statement = "UpdateClob('$CFG->prefix$table', '$key', '" . substr($value, 0, 100) . "...', '$sqlcondition')";
debugging($db->ErrorMsg() ."<br /><br />$statement");
if (!empty($CFG->dblogerror)) {
$debug=array_shift(debug_backtrace());
error_log("SQL ".$db->ErrorMsg()." in {$debug['file']} on line {$debug['line']}. STATEMENT: $statement");
}
}
}
}
/// Update all the blobs
if ($blobs) {
foreach ($blobs as $key => $value) {
if (defined('MDL_PERFDB')) { global $PERF ; $PERF->dbqueries++; }; /// Count the extra updates in PERF
if(!$db->UpdateBlob($CFG->prefix.$table, $key, $value, $sqlcondition)) {
$status = false;
$statement = "UpdateBlob('$CFG->prefix$table', '$key', '" . substr($value, 0, 100) . "...', '$sqlcondition')";
debugging($db->ErrorMsg() ."<br /><br />$statement");
if (!empty($CFG->dblogerror)) {
$debug=array_shift(debug_backtrace());
error_log("SQL ".$db->ErrorMsg()." in {$debug['file']} on line {$debug['line']}. STATEMENT: $statement");
}
}
}
}
return $status;
}
/**
* Set cached record.
*
* If you have called rcache_getforfill() before, it will also
* release the lock.
*
* This function is private and must not be used outside dmllib at all
*
* @param $table string
* @param $id integer
* @param $rec obj
* @return bool
*/
function rcache_set($table, $id, $rec) {
global $CFG, $MCACHE, $rcache;
if ($CFG->rcache === 'internal') {
$rcache->data[$table][$id] = $rec;
} else {
$key = $table . '|' . $id;
if (isset($MCACHE)) {
// $table is a flag used to mark
// a table as dirty & uncacheable
// when an UPDATE or DELETE not bound by ID
// is taking place
if (!$MCACHE->get($table)) {
// this will also release the _forfill lock
$MCACHE->set($key, $rec, $CFG->rcachettl);
}
}
}
return true;
}
/**
* Unset cached record if it exists.
*
* This function is private and must not be used outside dmllib at all
*
* @param $table string
* @param $id integer
* @return bool
*/
function rcache_unset($table, $id) {
global $CFG, $MCACHE, $rcache;
if ($CFG->rcache === 'internal') {
if (isset($rcache->data[$table][$id])) {
unset($rcache->data[$table][$id]);
}
} else {
$key = $table . '|' . $id;
if (isset($MCACHE)) {
$MCACHE->delete($key);
}
}
return true;
}
/**
* Get cached record if available. ONLY use if you
* are trying to get the cached record and will NOT
* fetch it yourself if not cached.
*
* Use rcache_getforfill() if you are going to fetch
* the record if not cached...
*
* This function is private and must not be used outside dmllib at all
*
* @param $table string
* @param $id integer
* @return mixed object-like record on cache hit, false otherwise
*/
function rcache_get($table, $id) {
global $CFG, $MCACHE, $rcache;
if ($CFG->rcache === 'internal') {
if (isset($rcache->data[$table][$id])) {
$rcache->hits++;
return $rcache->data[$table][$id];
} else {
$rcache->misses++;
return false;
}
}
if (isset($MCACHE)) {
$key = $table . '|' . $id;
// we set $table as a flag used to mark
// a table as dirty & uncacheable
// when an UPDATE or DELETE not bound by ID
// is taking place
if ($MCACHE->get($table)) {
$rcache->misses++;
return false;
} else {
$rec = $MCACHE->get($key);
if (!empty($rec)) {
$rcache->hits++;
return $rec;
} else {
$rcache->misses++;
return false;
}
}
}
return false;
}
/**
* Get cached record if available. In most cases you want
* to use this function -- namely if you are trying to get
* the cached record and will fetch it yourself if not cached.
* (and set the cache ;-)
*
* Uses the getforfill caching mechanism. See lib/eaccelerator.class.php
* for a detailed description of the technique.
*
* Note: if you call rcache_getforfill() you are making an implicit promise
* that if the cache is empty, you will later populate it, or cancel the promise
* calling rcache_releaseforfill();
*
* This function is private and must not be used outside dmllib at all
*
* @param $table string
* @param $id integer
* @return mixed object-like record on cache hit, false otherwise
*/
function rcache_getforfill($table, $id) {
global $CFG, $MCACHE, $rcache;
if ($CFG->rcache === 'internal') {
return rcache_get($table, $id);
}
if (isset($MCACHE)) {
$key = $table . '|' . $id;
// if $table is set - we won't take the
// lock either
if ($MCACHE->get($table)) {
$rcache->misses++;
return false;
}
$rec = $MCACHE->getforfill($key);
if (!empty($rec)) {
$rcache->hits++;
return $rec;
}
$rcache->misses++;
return false;
}
return false;
}
/**
* Release the exclusive lock obtained by
* rcache_getforfill(). See rcache_getforfill()
* for more details.
*
* This function is private and must not be used outside dmllib at all
*
* @param $table string
* @param $id integer
* @return bool
*/
function rcache_releaseforfill($table, $id) {
global $CFG, $MCACHE;
if (isset($MCACHE)) {
$key = $table . '|' . $id;
return $MCACHE->releaseforfill($key);
}
return true;
}
/**
* Remove or invalidate all rcache entries related to
* a table. Not all caching mechanisms cluster entries
* by table so in those cases we use alternative strategies.
*
* This function is private and must not be used outside dmllib at all
*
* @param $table string the table to invalidate records for
* @return bool
*/
function rcache_unset_table ($table) {
global $CFG, $MCACHE, $rcache;
if ($CFG->rcache === 'internal') {
if (isset($rcache->data[$table])) {
unset($rcache->data[$table]);
}
return true;
}
if (isset($MCACHE)) {
// at least as long as content keys to ensure they expire
// before the dirty flag
$MCACHE->set($tablekey, true, $CFG->rcachettl);
}
return true;
}
?>
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