From 0f0d3c62e608287cdf77f1a3239371b521ecb40b Mon Sep 17 00:00:00 2001
From: wei <>
Date: Sat, 14 Apr 2007 05:02:29 +0000
Subject: Refactor ActiveRecordGateway to use TDataGatewayCommand

---
 .../Data/Common/Mssql/TMssqlCommandBuilder.php     | 173 +++++++++++++++++++++
 1 file changed, 173 insertions(+)
 create mode 100644 framework/Data/Common/Mssql/TMssqlCommandBuilder.php

(limited to 'framework/Data/Common/Mssql/TMssqlCommandBuilder.php')

diff --git a/framework/Data/Common/Mssql/TMssqlCommandBuilder.php b/framework/Data/Common/Mssql/TMssqlCommandBuilder.php
new file mode 100644
index 00000000..b22c08a5
--- /dev/null
+++ b/framework/Data/Common/Mssql/TMssqlCommandBuilder.php
@@ -0,0 +1,173 @@
+<?php
+/**
+ * TDbCommandBuilder class file.
+ *
+ * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
+ * @link http://www.pradosoft.com/
+ * @copyright Copyright &copy; 2005-2007 PradoSoft
+ * @license http://www.pradosoft.com/license/
+ * @version $Id: TDbCommandBuilder.php 1863 2007-04-12 12:43:49Z wei $
+ * @package System.Data.Common
+ */
+
+Prado::using('System.Data.Common.TDbCommandBuilder');
+
+/**
+ * TDbCommandBuilder provides basic methods to create query commands for tables
+ * giving by {@link setTableInfo TableInfo} the property.
+ *
+ * @author Wei Zhuo <weizho[at]gmail[dot]com>
+ * @version $Id: TDbCommandBuilder.php 1863 2007-04-12 12:43:49Z wei $
+ * @package System.Data.Common
+ * @since 3.1
+ */
+class TMssqlCommandBuilder extends TDbCommandBuilder
+{
+	/**
+	 * Overrides parent implementation. Uses "SELECT @@Identity".
+	 * @return integer last insert id, null if none is found.
+	 */
+	public function getLastInsertID()
+	{
+		foreach($this->getTableInfo()->getColumns() as $column)
+		{
+			if($column->hasSequence())
+			{
+				$command = $this->getDbConnection()->createCommand('SELECT @@Identity');
+				return intval($command->queryScalar());
+			}
+		}
+	}
+
+	/**
+	 * Overrides parent implementation. Alters the sql to apply $limit and $offset.
+	 * The idea for limit with offset is done by modifying the sql on the fly
+	 * with numerous assumptions on the structure of the sql string.
+	 * The modification is done with reference to the notes from
+	 * http://troels.arvin.dk/db/rdbms/#select-limit-offset
+	 *
+	 * <code>
+	 * SELECT * FROM (
+	 *  SELECT TOP n * FROM (
+	 *    SELECT TOP z columns      -- (z=n+skip)
+	 *    FROM tablename
+	 *    ORDER BY key ASC
+	 *  ) AS FOO ORDER BY key DESC -- ('FOO' may be anything)
+	 * ) AS BAR ORDER BY key ASC    -- ('BAR' may be anything)
+	 * </code>
+	 *
+	 * <b>Regular expressions are used to alter the SQL query. The resulting SQL query
+	 * may be malformed for complex queries.</b> The following restrictions apply
+	 *
+	 * <ul>
+	 *   <li>
+	 * In particular, <b>commas</b> should <b>NOT</b>
+	 * be used as part of the ordering expression or identifier. Commas must only be
+	 * used for separating the ordering clauses.
+	 *  </li>
+	 *  <li>
+	 * In the ORDER BY clause, the column name should NOT be be qualified
+	 * with a table name or view name. Alias the column names or use column index.
+	 * </li>
+	 * <li>
+	 * No clauses should follow the ORDER BY clause, e.g. no COMPUTE or FOR clauses.
+	 * </li>
+	 *
+	 * @param string SQL query string.
+	 * @param integer maximum number of rows, -1 to ignore limit.
+	 * @param integer row offset, -1 to ignore offset.
+	 * @return string SQL with limit and offset.
+	 */
+	public function applyLimitOffset($sql, $limit=-1, $offset=-1)
+	{
+		$limit = $limit!==null ? intval($limit) : -1;
+		$offset = $offset!==null ? intval($offset) : -1;
+		if ($limit > 0 && $offset <= 0) //just limit
+			$sql = preg_replace('/^([\s(])*SELECT( DISTINCT)?(?!\s*TOP\s*\()/i',"\\1SELECT\\2 TOP $limit", $sql);
+		else if($limit > 0 && $offset > 0)
+			$sql = $this->rewriteLimitOffsetSql($sql, $limit,$offset);
+		return $sql;
+	}
+
+	/**
+	 * Rewrite sql to apply $limit > and $offset > 0 for MSSQL database.
+	 * See http://troels.arvin.dk/db/rdbms/#select-limit-offset
+	 * @param string sql query
+	 * @param integer $limit > 0
+	 * @param integer $offset > 0
+	 * @return sql modified sql query applied with limit and offset.
+	 */
+	protected function rewriteLimitOffsetSql($sql, $limit, $offset)
+	{
+		$fetch = $limit+$offset;
+		$sql = preg_replace('/^([\s(])*SELECT( DISTINCT)?(?!\s*TOP\s*\()/i',"\\1SELECT\\2 TOP $fetch", $sql);
+		$ordering = $this->findOrdering($sql);
+
+		$orginalOrdering = $this->joinOrdering($ordering);
+		$reverseOrdering = $this->joinOrdering($this->reverseDirection($ordering));
+		$sql = "SELECT * FROM (SELECT TOP {$limit} * FROM ($sql) as [__inner top table__] {$reverseOrdering}) as [__outer top table__] {$orginalOrdering}";
+		return $sql;
+	}
+
+	/**
+	 * Base on simplified syntax http://msdn2.microsoft.com/en-us/library/aa259187(SQL.80).aspx
+	 *
+	 * @param string $sql
+	 * @return array ordering expression as key and ordering direction as value
+	 */
+	protected function findOrdering($sql)
+	{
+		if(!preg_match('/ORDER BY/i', $sql))
+			return array();
+		$matches=array();
+		$ordering=array();
+		preg_match_all('/(ORDER BY)[\s"\[](.*)(ASC|DESC)?(?:[\s"\[]|$|COMPUTE|FOR)/i', $sql, $matches);
+		if(count($matches)>1 && count($matches[2]) > 0)
+		{
+			$parts = explode(',', $matches[2][0]);
+			foreach($parts as $part)
+			{
+				$subs=array();
+				if(preg_match_all('/(.*)[\s"\]](ASC|DESC)$/i', trim($part), $subs))
+				{
+					if(count($subs) > 1 && count($subs[2]) > 0)
+					{
+						$ordering[$subs[1][0]] = $subs[2][0];
+					}
+					//else what?
+				}
+				else
+					$ordering[trim($part)] = 'ASC';
+			}
+		}
+		return $ordering;
+	}
+
+	/**
+	 * @param array ordering obtained from findOrdering()
+	 * @return string concat the orderings
+	 */
+	protected function joinOrdering($orders)
+	{
+		if(count($orders)>0)
+		{
+			$str=array();
+			foreach($orders as $column => $direction)
+				$str[] = $column.' '.$direction;
+			return 'ORDER BY '.implode(', ', $str);
+		}
+	}
+
+	/**
+	 * @param array original ordering
+	 * @return array ordering with reversed direction.
+	 */
+	protected function reverseDirection($orders)
+	{
+		foreach($orders as $column => $direction)
+			$orders[$column] = strtolower(trim($direction))==='desc' ? 'ASC' : 'DESC';
+		return $orders;
+	}
+}
+
+?>
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