Merge remote-tracking branch 'nickvergessen/ticket/10942' into develop

* nickvergessen/ticket/10942:
  [ticket/10942] Avoid possible conflicts with magic words in unit tests
  [ticket/10942] Add access modifiers
  [ticket/10942] Use ANSI SQL standard || in dbal.php
  [ticket/10942] Fix up unit tests for sql_case()
  [ticket/10942] Require same data type and do not cast expressions automatically
  [ticket/10942] Make unit tests for sql_case simpler
  [ticket/10942] Add a comment why we cast to sql_case()
  [ticket/10942] Rename method sql_conditional() to sql_case()
  [ticket/10942] Change term string to expression to avoid confusion
  [ticket/10942] Fix sql_conditional for mssql, postgre and oracle
  [ticket/10942] Fix function name on order_lower_test.php
  [ticket/10942] Add unit tests for sql_concatenate
  [ticket/10942] Add sql_concatenate to dbal
  [ticket/10942] Add unit tests for sql_conditional
  [ticket/10942] Add sql_conditional to dbal

phpBB/includes/db/dbal.php

@@ -283,6 +283,37 @@ class dbal
 		return $this->_sql_like_expression('LIKE \'' . $this->sql_escape($expression) . '\'');
 	}
 
+	/**
+	* Build a case expression
+	*
+	* Note: The two statements action_true and action_false must have the same data type (int, vchar, ...) in the database!
+	*
+	* @param	string	$condition		The condition which must be true, to use action_true rather then action_else
+	* @param	string	$action_true	SQL expression that is used, if the condition is true
+	* @param	string	$action_else	SQL expression that is used, if the condition is false, optional
+	* @return	string			CASE expression including the condition and statements
+	*/
+	public function sql_case($condition, $action_true, $action_false = false)
+	{
+		$sql_case = 'CASE WHEN ' . $condition;
+		$sql_case .= ' THEN ' . $action_true;
+		$sql_case .= ($action_false !== false) ? ' ELSE ' . $action_false : '';
+		$sql_case .= ' END';
+		return $sql_case;
+	}
+
+	/**
+	* Build a concatenated expression
+	*
+	* @param	string	$expr1		Base SQL expression where we append the second one
+	* @param	string	$expr2		SQL expression that is appended to the first expression
+	* @return	string		Concatenated string
+	*/
+	public function sql_concatenate($expr1, $expr2)
+	{
+		return $expr1 . ' || ' . $expr2;
+	}
+
 	/**
 	* Returns whether results of a query need to be buffered to run a transaction while iterating over them.
 	*

phpBB/includes/db/mssql.php

@@ -91,6 +91,14 @@ class dbal_mssql extends dbal
 		return ($this->sql_server_version) ? 'MSSQL<br />' . $this->sql_server_version : 'MSSQL';
 	}
 
+	/**
+	* {@inheritDoc}
+	*/
+	public function sql_concatenate($expr1, $expr2)
+	{
+		return $expr1 . ' + ' . $expr2;
+	}
+
 	/**
 	* SQL Transaction
 	* @access private

phpBB/includes/db/mssql_odbc.php

@@ -109,6 +109,14 @@ class dbal_mssql_odbc extends dbal
 		return ($this->sql_server_version) ? 'MSSQL (ODBC)<br />' . $this->sql_server_version : 'MSSQL (ODBC)';
 	}
 
+	/**
+	* {@inheritDoc}
+	*/
+	public function sql_concatenate($expr1, $expr2)
+	{
+		return $expr1 . ' + ' . $expr2;
+	}
+
 	/**
 	* SQL Transaction
 	* @access private

phpBB/includes/db/mssqlnative.php

@@ -257,6 +257,14 @@ class dbal_mssqlnative extends dbal
 		return ($this->sql_server_version) ? 'MSSQL<br />' . $this->sql_server_version : 'MSSQL';
 	}
 
+	/**
+	* {@inheritDoc}
+	*/
+	public function sql_concatenate($expr1, $expr2)
+	{
+		return $expr1 . ' + ' . $expr2;
+	}
+
 	/**
 	* {@inheritDoc}
 	*/

phpBB/includes/db/mysql.php

@@ -119,6 +119,14 @@ class dbal_mysql extends dbal
 		return ($raw) ? $this->sql_server_version : 'MySQL ' . $this->sql_server_version;
 	}
 
+	/**
+	* {@inheritDoc}
+	*/
+	public function sql_concatenate($expr1, $expr2)
+	{
+		return 'CONCAT(' . $expr1 . ', ' . $expr2 . ')';
+	}
+
 	/**
 	* SQL Transaction
 	* @access private

phpBB/includes/db/mysqli.php

@@ -122,6 +122,14 @@ class dbal_mysqli extends dbal
 		return ($raw) ? $this->sql_server_version : 'MySQL(i) ' . $this->sql_server_version;
 	}
 
+	/**
+	* {@inheritDoc}
+	*/
+	public function sql_concatenate($expr1, $expr2)
+	{
+		return 'CONCAT(' . $expr1 . ', ' . $expr2 . ')';
+	}
+
 	/**
 	* SQL Transaction
 	* @access private