mirror of
https://github.com/moodle/moodle.git
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490 lines
22 KiB
PHP
490 lines
22 KiB
PHP
<?php
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// This file is part of Moodle - http://moodle.org/
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//
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// Moodle is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// Moodle is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
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/**
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* PostgreSQL specific SQL code generator.
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*
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* @package moodlecore
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* @subpackage DDL
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* @copyright 1999 onwards Martin Dougiamas http://dougiamas.com
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* 2001-3001 Eloy Lafuente (stronk7) http://contiento.com
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* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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*/
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require_once($CFG->libdir.'/ddl/sql_generator.php');
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/// This class generate SQL code to be used against PostgreSQL
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/// It extends XMLDBgenerator so everything can be
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/// overriden as needed to generate correct SQL.
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class postgres_sql_generator extends sql_generator {
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/// Only set values that are different from the defaults present in XMLDBgenerator
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public $number_type = 'NUMERIC'; // Proper type for NUMBER(x) in this DB
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public $unsigned_allowed = false; // To define in the generator must handle unsigned information
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public $default_for_char = ''; // To define the default to set for NOT NULLs CHARs without default (null=do nothing)
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public $sequence_extra_code = false; //Does the generator need to add extra code to generate the sequence fields
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public $sequence_name = 'BIGSERIAL'; //Particular name for inline sequences in this generator
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public $sequence_name_small = 'SERIAL'; //Particular name for inline sequences in this generator
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public $sequence_only = true; //To avoid to output the rest of the field specs, leaving only the name and the sequence_name variable
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public $enum_inline_code = false; //Does the generator need to add inline code in the column definition
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public $rename_index_sql = 'ALTER TABLE OLDINDEXNAME RENAME TO NEWINDEXNAME'; //SQL sentence to rename one index
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//TABLENAME, OLDINDEXNAME, NEWINDEXNAME are dinamically replaced
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public $rename_key_sql = null; //SQL sentence to rename one key (PostgreSQL doesn't support this!)
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//TABLENAME, OLDKEYNAME, NEWKEYNAME are dinamically replaced
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/**
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* Reset a sequence to the id field of a table.
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* @param string $table name of table or xmldb_table object
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* @return array sql commands to execute
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*/
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public function getResetSequenceSQL($table) {
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if ($table instanceof xmldb_table) {
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$tablename = $table->getName();
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} else {
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$tablename = $table;
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}
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// From http://www.postgresql.org/docs/7.4/static/sql-altersequence.html
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$value = (int)$this->mdb->get_field_sql('SELECT MAX(id) FROM {'.$tablename.'}');
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$value++;
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return array("ALTER SEQUENCE $this->prefix{$tablename}_id_seq RESTART WITH $value");
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}
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/**
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* Given one correct xmldb_table, returns the SQL statements
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* to create temporary table (inside one array)
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*/
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public function getCreateTempTableSQL($xmldb_table) {
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$this->temptables->add_temptable($xmldb_table->getName());
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$sqlarr = $this->getCreateTableSQL($xmldb_table);
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$sqlarr = preg_replace('/^CREATE TABLE/', "CREATE TEMPORARY TABLE", $sqlarr);
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return $sqlarr;
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}
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/**
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* Given one correct xmldb_table and the new name, returns the SQL statements
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* to drop it (inside one array)
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*/
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public function getDropTempTableSQL($xmldb_table) {
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$sqlarr = $this->getDropTableSQL($xmldb_table);
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$this->temptables->delete_temptable($xmldb_table->getName());
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return $sqlarr;
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}
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/**
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* Given one XMLDB Type, lenght and decimals, returns the DB proper SQL type
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*/
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public function getTypeSQL($xmldb_type, $xmldb_length=null, $xmldb_decimals=null) {
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switch ($xmldb_type) {
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case XMLDB_TYPE_INTEGER: // From http://www.postgresql.org/docs/7.4/interactive/datatype.html
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if (empty($xmldb_length)) {
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$xmldb_length = 10;
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}
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if ($xmldb_length > 9) {
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$dbtype = 'BIGINT';
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} else if ($xmldb_length > 4) {
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$dbtype = 'INTEGER';
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} else {
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$dbtype = 'SMALLINT';
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}
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break;
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case XMLDB_TYPE_NUMBER:
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$dbtype = $this->number_type;
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if (!empty($xmldb_length)) {
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$dbtype .= '(' . $xmldb_length;
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if (!empty($xmldb_decimals)) {
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$dbtype .= ',' . $xmldb_decimals;
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}
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$dbtype .= ')';
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}
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break;
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case XMLDB_TYPE_FLOAT:
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$dbtype = 'DOUBLE PRECISION';
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if (!empty($xmldb_decimals)) {
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if ($xmldb_decimals < 6) {
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$dbtype = 'REAL';
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}
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}
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break;
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case XMLDB_TYPE_CHAR:
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$dbtype = 'VARCHAR';
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if (empty($xmldb_length)) {
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$xmldb_length='255';
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}
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$dbtype .= '(' . $xmldb_length . ')';
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break;
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case XMLDB_TYPE_TEXT:
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$dbtype = 'TEXT';
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break;
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case XMLDB_TYPE_BINARY:
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$dbtype = 'BYTEA';
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break;
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case XMLDB_TYPE_DATETIME:
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$dbtype = 'TIMESTAMP';
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break;
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}
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return $dbtype;
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}
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/**
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* Returns the code (in array) needed to add one comment to the table
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*/
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function getCommentSQL ($xmldb_table) {
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$comment = "COMMENT ON TABLE " . $this->getTableName($xmldb_table);
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$comment.= " IS '" . $this->addslashes(substr($xmldb_table->getComment(), 0, 250)) . "'";
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return array($comment);
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}
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/**
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* Returns the code (array of statements) needed to execute extra statements on table rename
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*/
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public function getRenameTableExtraSQL($xmldb_table, $newname) {
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$results = array();
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$newt = new xmldb_table($newname);
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$xmldb_field = new xmldb_field('id'); // Fields having sequences should be exclusively, id.
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$oldseqname = $this->getTableName($xmldb_table) . '_' . $xmldb_field->getName() . '_seq';
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$newseqname = $this->getTableName($newt) . '_' . $xmldb_field->getName() . '_seq';
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/// Rename de sequence
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$results[] = 'ALTER TABLE ' . $oldseqname . ' RENAME TO ' . $newseqname;
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/// Rename all the check constraints in the table
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$oldtablename = $this->getTableName($xmldb_table);
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$newtablename = $this->getTableName($newt);
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$oldconstraintprefix = $this->getNameForObject($xmldb_table->getName(), '');
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$newconstraintprefix = $this->getNameForObject($newt->getName(), '', '');
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if ($constraints = $this->getCheckConstraintsFromDB($xmldb_table)) {
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foreach ($constraints as $constraint) {
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/// Drop the old constraint
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$results[] = 'ALTER TABLE ' . $newtablename . ' DROP CONSTRAINT ' . $constraint->name;
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}
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}
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return $results;
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}
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/**
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* Given one xmldb_table and one xmldb_field, return the SQL statements needded to alter the field in the table
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* PostgreSQL has some severe limits:
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* - Any change of type or precision requires a new temporary column to be created, values to
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* be transfered potentially casting them, to apply defaults if the column is not null and
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* finally, to rename it
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* - Changes in null/not null require the SET/DROP NOT NULL clause
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* - Changes in default require the SET/DROP DEFAULT clause
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*/
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public function getAlterFieldSQL($xmldb_table, $xmldb_field) {
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$results = array(); /// To store all the needed SQL commands
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/// Get the normla names of the table and field
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$tablename = $xmldb_table->getName();
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$fieldname = $xmldb_field->getName();
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/// Take a look to field metadata
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$meta = $this->mdb->get_columns($tablename);
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$metac = $meta[$xmldb_field->getName()];
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$oldmetatype = $metac->meta_type;
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$oldlength = $metac->max_length;
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$olddecimals = empty($metac->scale) ? null : $metac->scale;
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$oldnotnull = empty($metac->not_null) ? false : $metac->not_null;
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$olddefault = empty($metac->has_default) ? null : $metac->default_value;
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$typechanged = true; //By default, assume that the column type has changed
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$precisionchanged = true; //By default, assume that the column precision has changed
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$decimalchanged = true; //By default, assume that the column decimal has changed
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$defaultchanged = true; //By default, assume that the column default has changed
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$notnullchanged = true; //By default, assume that the column notnull has changed
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/// Detect if we are changing the type of the column
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if (($xmldb_field->getType() == XMLDB_TYPE_INTEGER && $oldmetatype == 'I') ||
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($xmldb_field->getType() == XMLDB_TYPE_NUMBER && $oldmetatype == 'N') ||
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($xmldb_field->getType() == XMLDB_TYPE_FLOAT && $oldmetatype == 'F') ||
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($xmldb_field->getType() == XMLDB_TYPE_CHAR && $oldmetatype == 'C') ||
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($xmldb_field->getType() == XMLDB_TYPE_TEXT && $oldmetatype == 'X') ||
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($xmldb_field->getType() == XMLDB_TYPE_BINARY && $oldmetatype == 'B')) {
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$typechanged = false;
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}
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/// Detect if we are changing the precision
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if (($xmldb_field->getType() == XMLDB_TYPE_TEXT) ||
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($xmldb_field->getType() == XMLDB_TYPE_BINARY) ||
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($oldlength == -1) ||
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($xmldb_field->getLength() == $oldlength)) {
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$precisionchanged = false;
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}
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/// Detect if we are changing the decimals
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if (($xmldb_field->getType() == XMLDB_TYPE_INTEGER) ||
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($xmldb_field->getType() == XMLDB_TYPE_CHAR) ||
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($xmldb_field->getType() == XMLDB_TYPE_TEXT) ||
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($xmldb_field->getType() == XMLDB_TYPE_BINARY) ||
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(!$xmldb_field->getDecimals()) ||
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(!$olddecimals) ||
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($xmldb_field->getDecimals() == $olddecimals)) {
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$decimalchanged = false;
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}
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/// Detect if we are changing the default
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if (($xmldb_field->getDefault() === null && $olddefault === null) ||
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($xmldb_field->getDefault() === $olddefault)) {
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$defaultchanged = false;
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}
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/// Detect if we are changing the nullability
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if (($xmldb_field->getNotnull() === $oldnotnull)) {
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$notnullchanged = false;
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}
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/// Get the quoted name of the table and field
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$tablename = $this->getTableName($xmldb_table);
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$fieldname = $this->getEncQuoted($xmldb_field->getName());
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/// Decide if we have changed the column specs (type/precision/decimals)
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$specschanged = $typechanged || $precisionchanged || $decimalchanged;
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/// if specs have changed, need to alter column
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if ($specschanged) {
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/// Always drop any exiting default before alter column (some type changes can cause casting error in default for column)
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if ($olddefault !== null) {
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$results[] = 'ALTER TABLE ' . $tablename . ' ALTER COLUMN ' . $fieldname . ' DROP DEFAULT'; /// Drop default clause
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}
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$alterstmt = 'ALTER TABLE ' . $tablename . ' ALTER COLUMN ' . $this->getEncQuoted($xmldb_field->getName()) .
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' TYPE' . $this->getFieldSQL($xmldb_field, null, true, true, null, false);
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/// Some castings must be performed explicity (mainly from text|char to numeric|integer)
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if (($oldmetatype == 'C' || $oldmetatype == 'X') &&
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($xmldb_field->getType() == XMLDB_TYPE_NUMBER || $xmldb_field->getType() == XMLDB_TYPE_FLOAT)) {
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$alterstmt .= ' USING CAST('.$fieldname.' AS NUMERIC)'; // from char or text to number or float
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} else if (($oldmetatype == 'C' || $oldmetatype == 'X') &&
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$xmldb_field->getType() == XMLDB_TYPE_INTEGER) {
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$alterstmt .= ' USING CAST(CAST('.$fieldname.' AS NUMERIC) AS INTEGER)'; // From char to integer
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}
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$results[] = $alterstmt;
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}
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/// If the default has changed or we have performed one change in specs
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if ($defaultchanged || $specschanged) {
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$default_clause = $this->getDefaultClause($xmldb_field);
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if ($default_clause) {
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$sql = 'ALTER TABLE ' . $tablename . ' ALTER COLUMN ' . $fieldname . ' SET' . $default_clause; /// Add default clause
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$results[] = $sql;
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} else {
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if (!$specschanged) { /// Only drop default if we haven't performed one specs change
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$results[] = 'ALTER TABLE ' . $tablename . ' ALTER COLUMN ' . $fieldname . ' DROP DEFAULT'; /// Drop default clause
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}
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}
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}
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/// If the not null has changed
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if ($notnullchanged) {
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if ($xmldb_field->getNotnull()) {
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$results[] = 'ALTER TABLE ' . $tablename . ' ALTER COLUMN ' . $fieldname . ' SET NOT NULL';
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} else {
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$results[] = 'ALTER TABLE ' . $tablename . ' ALTER COLUMN ' . $fieldname . ' DROP NOT NULL';
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}
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}
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/// Return the results
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return $results;
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}
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/**
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* Given one xmldb_table and one xmldb_field, return the SQL statements needded to drop its enum
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* (usually invoked from getModifyEnumSQL()
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*
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* TODO: Moodle 2.1 - drop in Moodle 2.1
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*/
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public function getDropEnumSQL($xmldb_table, $xmldb_field) {
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/// Let's introspect to know the real name of the check constraint
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if ($check_constraints = $this->getCheckConstraintsFromDB($xmldb_table, $xmldb_field)) {
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$check_constraint = array_shift($check_constraints); /// Get the 1st (should be only one)
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$constraint_name = strtolower($check_constraint->name); /// Extract the REAL name
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/// All we have to do is to drop the check constraint
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return array('ALTER TABLE ' . $this->getTableName($xmldb_table) .
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' DROP CONSTRAINT ' . $constraint_name);
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} else { /// Constraint not found. Nothing to do
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return array();
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}
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}
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/**
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* Given one xmldb_table and one xmldb_field, return the SQL statements needded to create its default
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* (usually invoked from getModifyDefaultSQL()
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*/
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public function getCreateDefaultSQL($xmldb_table, $xmldb_field) {
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/// Just a wrapper over the getAlterFieldSQL() function for PostgreSQL that
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/// is capable of handling defaults
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return $this->getAlterFieldSQL($xmldb_table, $xmldb_field);
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}
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/**
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* Given one xmldb_table and one xmldb_field, return the SQL statements needded to drop its default
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* (usually invoked from getModifyDefaultSQL()
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*/
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public function getDropDefaultSQL($xmldb_table, $xmldb_field) {
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/// Just a wrapper over the getAlterFieldSQL() function for PostgreSQL that
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/// is capable of handling defaults
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return $this->getAlterFieldSQL($xmldb_table, $xmldb_field);
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}
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/**
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* Given one xmldb_table returns one array with all the check constrainsts
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* in the table (fetched from DB)
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* Optionally the function allows one xmldb_field to be specified in
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* order to return only the check constraints belonging to one field.
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* Each element contains the name of the constraint and its description
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* If no check constraints are found, returns an empty array
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*
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* TODO: Moodle 2.1 - drop in Moodle 2.1
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*/
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public function getCheckConstraintsFromDB($xmldb_table, $xmldb_field = null) {
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$results = array();
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$tablename = $this->getTableName($xmldb_table);
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if ($constraints = $this->mdb->get_records_sql("SELECT co.conname AS name, co.consrc AS description
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FROM pg_constraint co, pg_class cl
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WHERE co.conrelid = cl.oid
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AND co.contype = 'c' AND cl.relname = ?",
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array($tablename))) {
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foreach ($constraints as $constraint) {
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$results[$constraint->name] = $constraint;
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}
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}
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/// Filter by the required field if specified
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if ($xmldb_field) {
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$filtered_results = array();
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$filter = $xmldb_field->getName();
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/// Lets clean a bit each constraint description, looking for the filtered field
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foreach ($results as $key => $result) {
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$description = preg_replace('/\("(.*?)"\)/', '($1)', $result->description);// Double quotes out
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$description = preg_replace('/[\(\)]/', '', $description); // Parenthesis out
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$description = preg_replace('/::[a-z]+/i', '', $description); // Casts out
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$description = preg_replace("/({$filter})/i", '@$1@', $description);
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$description = trim(preg_replace('/ or /i', ' OR ', $description)); // Uppercase or & trim
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/// description starts by @$filter@ assume it's a constraint beloging to the field
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if (preg_match("/^@{$filter}@/i", $description)) {
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$filtered_results[$key] = $result;
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}
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}
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/// Assign filtered results to the final results array
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$results = $filtered_results;
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}
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return $results;
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}
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/**
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* Given one xmldb_table returns one string with the sequence of the table
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* in the table (fetched from DB)
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* The sequence name for Postgres has one standard name convention:
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* tablename_fieldname_seq
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* so we just calculate it and confirm it's present in pg_class
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* If no sequence is found, returns false
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*/
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function getSequenceFromDB($xmldb_table) {
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$tablename = $this->getTableName($xmldb_table);
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$sequencename = $tablename . '_id_seq';
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if (!$this->mdb->get_record_sql("SELECT *
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FROM pg_class
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WHERE relname = ? AND relkind = 'S'",
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array($sequencename))) {
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$sequencename = false;
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}
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return $sequencename;
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}
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/**
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* Given one object name and it's type (pk, uk, fk, ck, ix, uix, seq, trg)
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* return if such name is currently in use (true) or no (false)
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* (invoked from getNameForObject()
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*/
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public function isNameInUse($object_name, $type, $table_name) {
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switch($type) {
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case 'ix':
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case 'uix':
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case 'seq':
|
|
if ($check = $this->mdb->get_records_sql("SELECT relname
|
|
FROM pg_class
|
|
WHERE lower(relname) = ?", array(strtolower($object_name)))) {
|
|
return true;
|
|
}
|
|
break;
|
|
case 'pk':
|
|
case 'uk':
|
|
case 'fk':
|
|
case 'ck':
|
|
if ($check = $this->mdb->get_records_sql("SELECT conname
|
|
FROM pg_constraint
|
|
WHERE lower(conname) = ?", array(strtolower($object_name)))) {
|
|
return true;
|
|
}
|
|
break;
|
|
case 'trg':
|
|
if ($check = $this->mdb->get_records_sql("SELECT tgname
|
|
FROM pg_trigger
|
|
WHERE lower(tgname) = ?", array(strtolower($object_name)))) {
|
|
return true;
|
|
}
|
|
break;
|
|
}
|
|
return false; //No name in use found
|
|
}
|
|
|
|
/**
|
|
* Returns an array of reserved words (lowercase) for this DB
|
|
*/
|
|
public static function getReservedWords() {
|
|
/// This file contains the reserved words for PostgreSQL databases
|
|
/// http://www.postgresql.org/docs/current/static/sql-keywords-appendix.html
|
|
$reserved_words = array (
|
|
'all', 'analyse', 'analyze', 'and', 'any', 'array', 'as', 'asc',
|
|
'asymmetric', 'authorization', 'between', 'binary', 'both', 'case',
|
|
'cast', 'check', 'collate', 'column', 'constraint', 'create', 'cross',
|
|
'current_date', 'current_role', 'current_time', 'current_timestamp',
|
|
'current_user', 'default', 'deferrable', 'desc', 'distinct', 'do',
|
|
'else', 'end', 'except', 'false', 'for', 'foreign', 'freeze', 'from',
|
|
'full', 'grant', 'group', 'having', 'ilike', 'in', 'initially', 'inner',
|
|
'intersect', 'into', 'is', 'isnull', 'join', 'leading', 'left', 'like',
|
|
'limit', 'localtime', 'localtimestamp', 'natural', 'new', 'not',
|
|
'notnull', 'null', 'off', 'offset', 'old', 'on', 'only', 'or', 'order',
|
|
'outer', 'overlaps', 'placing', 'primary', 'references', 'returning', 'right', 'select',
|
|
'session_user', 'similar', 'some', 'symmetric', 'table', 'then', 'to',
|
|
'trailing', 'true', 'union', 'unique', 'user', 'using', 'verbose',
|
|
'when', 'where', 'with'
|
|
);
|
|
return $reserved_words;
|
|
}
|
|
}
|