diff options
Diffstat (limited to 'framework/Data/Common/Mssql/TMssqlCommandBuilder.php')
| -rw-r--r-- | framework/Data/Common/Mssql/TMssqlCommandBuilder.php | 173 |
1 files changed, 173 insertions, 0 deletions
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 © 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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