<?php
/**
 * CSqliteCommandBuilder class file.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.yiiframework.com/
 * @copyright 2008-2013 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

/**
 * CSqliteCommandBuilder provides basic methods to create query commands for SQLite tables.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package system.db.schema.sqlite
 * @since 1.0
 */
class CSqliteCommandBuilder extends CDbCommandBuilder
{
	/**
	 * Generates the expression for selecting rows with specified composite key values.
	 * This method is overridden because SQLite does not support the default
	 * IN expression with composite columns.
	 * @param CDbTableSchema $table the table schema
	 * @param array $values list of primary key values to be selected within
	 * @param string $prefix column prefix (ended with dot)
	 * @return string the expression for selection
	 */
	protected function createCompositeInCondition($table,$values,$prefix)
	{
		$keyNames=array();
		foreach(array_keys($values[0]) as $name)
			$keyNames[]=$prefix.$table->columns[$name]->rawName;
		$vs=array();
		foreach($values as $value)
			$vs[]=implode("||','||",$value);
		return implode("||','||",$keyNames).' IN ('.implode(', ',$vs).')';
	}

	/**
	 * Creates a multiple INSERT command.
	 * This method could be used to achieve better performance during insertion of the large
	 * amount of data into the database tables.
	 * Note that SQLite does not keep original order of the inserted rows.
	 * @param mixed $table the table schema ({@link CDbTableSchema}) or the table name (string).
	 * @param array[] $data list data to be inserted, each value should be an array in format (column name=>column value).
	 * If a key is not a valid column name, the corresponding value will be ignored.
	 * @return CDbCommand multiple insert command
	 * @since 1.1.14
	 */
	public function createMultipleInsertCommand($table,array $data)
	{
		$templates=array(
			'main'=>'INSERT INTO {{tableName}} ({{columnInsertNames}}) {{rowInsertValues}}',
			'columnInsertValue'=>'{{value}} AS {{column}}',
			'columnInsertValueGlue'=>', ',
			'rowInsertValue'=>'SELECT {{columnInsertValues}}',
			'rowInsertValueGlue'=>' UNION ',
			'columnInsertNameGlue'=>', ',
		);
		return $this->composeMultipleInsertCommand($table,$data,$templates);
	}
}