<?php
/**
* CakePHP(tm) : Rapid Development Framework (https://cakephp.org)
* Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
*
* Licensed under The MIT License
* For full copyright and license information, please see the LICENSE.txt
* Redistributions of files must retain the above copyright notice.
*
* @copyright Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
* @link https://cakephp.org CakePHP(tm) Project
* @since 3.0.0
* @license https://opensource.org/licenses/mit-license.php MIT License
*/
namespace Cake\Database\Dialect;
use Cake\Database\ExpressionInterface;
use Cake\Database\Expression\FunctionExpression;
use Cake\Database\Expression\OrderByExpression;
use Cake\Database\Expression\UnaryExpression;
use Cake\Database\Query;
use Cake\Database\Schema\SqlserverSchema;
use Cake\Database\SqlDialectTrait;
use Cake\Database\SqlserverCompiler;
use Cake\Database\ValueBinder;
use PDO;
/**
* Contains functions that encapsulates the SQL dialect used by SQLServer,
* including query translators and schema introspection.
*
* @internal
*/
trait SqlserverDialectTrait
{
use SqlDialectTrait;
use TupleComparisonTranslatorTrait;
/**
* String used to start a database identifier quoting to make it safe
*
* @var string
*/
protected $_startQuote = '[';
/**
* String used to end a database identifier quoting to make it safe
*
* @var string
*/
protected $_endQuote = ']';
/**
* Modify the limit/offset to TSQL
*
* @param \Cake\Database\Query $query The query to translate
* @return \Cake\Database\Query The modified query
*/
protected function _selectQueryTranslator($query)
{
$limit = $query->clause('limit');
$offset = $query->clause('offset');
if ($limit && $offset === null) {
$query->modifier(['_auto_top_' => sprintf('TOP %d', $limit)]);
}
if ($offset !== null && !$query->clause('order')) {
$query->order($query->newExpr()->add('(SELECT NULL)'));
}
if ($this->_version() < 11 && $offset !== null) {
return $this->_pagingSubquery($query, $limit, $offset);
}
return $this->_transformDistinct($query);
}
/**
* Get the version of SQLserver we are connected to.
*
* @return int
*/
// @codingStandardsIgnoreLine
public function _version()
{
$this->connect();
return $this->_connection->getAttribute(PDO::ATTR_SERVER_VERSION);
}
/**
* Generate a paging subquery for older versions of SQLserver.
*
* Prior to SQLServer 2012 there was no equivalent to LIMIT OFFSET, so a subquery must
* be used.
*
* @param \Cake\Database\Query $original The query to wrap in a subquery.
* @param int $limit The number of rows to fetch.
* @param int $offset The number of rows to offset.
* @return \Cake\Database\Query Modified query object.
*/
protected function _pagingSubquery($original, $limit, $offset)
{
$field = '_cake_paging_._cake_page_rownum_';
if ($original->clause('order')) {
// SQL server does not support column aliases in OVER clauses. But
// the only practical way to specify the use of calculated columns
// is with their alias. So substitute the select SQL in place of
// any column aliases for those entries in the order clause.
$select = $original->clause('select');
$order = new OrderByExpression();
$original
->clause('order')
->iterateParts(function ($direction, $orderBy) use ($select, $order) {
$key = $orderBy;
if (isset($select[$orderBy]) &&
$select[$orderBy] instanceof ExpressionInterface
) {
$key = $select[$orderBy]->sql(new ValueBinder());
}
$order->add([$key => $direction]);
// Leave original order clause unchanged.
return $orderBy;
});
} else {
$order = new OrderByExpression('(SELECT NULL)');
}
$query = clone $original;
$query->select([
'_cake_page_rownum_' => new UnaryExpression('ROW_NUMBER() OVER', $order)
])->limit(null)
->offset(null)
->order([], true);
$outer = new Query($query->getConnection());
$outer->select('*')
->from(['_cake_paging_' => $query]);
if ($offset) {
$outer->where(["$field > " . (int)$offset]);
}
if ($limit) {
$value = (int)$offset + (int)$limit;
$outer->where(["$field <= $value"]);
}
// Decorate the original query as that is what the
// end developer will be calling execute() on originally.
$original->decorateResults(function ($row) {
if (isset($row['_cake_page_rownum_'])) {
unset($row['_cake_page_rownum_']);
}
return $row;
});
return $outer;
}
/**
* Returns the passed query after rewriting the DISTINCT clause, so that drivers
* that do not support the "ON" part can provide the actual way it should be done
*
* @param \Cake\Database\Query $original The query to be transformed
* @return \Cake\Database\Query
*/
protected function _transformDistinct($original)
{
if (!is_array($original->clause('distinct'))) {
return $original;
}
$query = clone $original;
$distinct = $query->clause('distinct');
$query->distinct(false);
$order = new OrderByExpression($distinct);
$query
->select(function ($q) use ($distinct, $order) {
$over = $q->newExpr('ROW_NUMBER() OVER')
->add('(PARTITION BY')
->add($q->newExpr()->add($distinct)->setConjunction(','))
->add($order)
->add(')')
->setConjunction(' ');
return [
'_cake_distinct_pivot_' => $over
];
})
->limit(null)
->offset(null)
->order([], true);
$outer = new Query($query->getConnection());
$outer->select('*')
->from(['_cake_distinct_' => $query])
->where(['_cake_distinct_pivot_' => 1]);
// Decorate the original query as that is what the
// end developer will be calling execute() on originally.
$original->decorateResults(function ($row) {
if (isset($row['_cake_distinct_pivot_'])) {
unset($row['_cake_distinct_pivot_']);
}
return $row;
});
return $outer;
}
/**
* Returns a dictionary of expressions to be transformed when compiling a Query
* to SQL. Array keys are method names to be called in this class
*
* @return array
*/
protected function _expressionTranslators()
{
$namespace = 'Cake\Database\Expression';
return [
$namespace . '\FunctionExpression' => '_transformFunctionExpression',
$namespace . '\TupleComparison' => '_transformTupleComparison'
];
}
/**
* Receives a FunctionExpression and changes it so that it conforms to this
* SQL dialect.
*
* @param \Cake\Database\Expression\FunctionExpression $expression The function expression to convert to TSQL.
* @return void
*/
protected function _transformFunctionExpression(FunctionExpression $expression)
{
switch ($expression->getName()) {
case 'CONCAT':
// CONCAT function is expressed as exp1 + exp2
$expression->setName('')->setConjunction(' +');
break;
case 'DATEDIFF':
$hasDay = false;
$visitor = function ($value) use (&$hasDay) {
if ($value === 'day') {
$hasDay = true;
}
return $value;
};
$expression->iterateParts($visitor);
if (!$hasDay) {
$expression->add(['day' => 'literal'], [], true);
}
break;
case 'CURRENT_DATE':
$time = new FunctionExpression('GETUTCDATE');
$expression->setName('CONVERT')->add(['date' => 'literal', $time]);
break;
case 'CURRENT_TIME':
$time = new FunctionExpression('GETUTCDATE');
$expression->setName('CONVERT')->add(['time' => 'literal', $time]);
break;
case 'NOW':
$expression->setName('GETUTCDATE');
break;
case 'EXTRACT':
$expression->setName('DATEPART')->setConjunction(' ,');
break;
case 'DATE_ADD':
$params = [];
$visitor = function ($p, $key) use (&$params) {
if ($key === 0) {
$params[2] = $p;
} else {
$valueUnit = explode(' ', $p);
$params[0] = rtrim($valueUnit[1], 's');
$params[1] = $valueUnit[0];
}
return $p;
};
$manipulator = function ($p, $key) use (&$params) {
return $params[$key];
};
$expression
->setName('DATEADD')
->setConjunction(',')
->iterateParts($visitor)
->iterateParts($manipulator)
->add([$params[2] => 'literal']);
break;
case 'DAYOFWEEK':
$expression
->setName('DATEPART')
->setConjunction(' ')
->add(['weekday, ' => 'literal'], [], true);
break;
case 'SUBSTR':
$expression->setName('SUBSTRING');
if (count($expression) < 4) {
$params = [];
$expression
->iterateParts(function ($p) use (&$params) {
return $params[] = $p;
})
->add([new FunctionExpression('LEN', [$params[0]]), ['string']]);
}
break;
}
}
/**
* Get the schema dialect.
*
* Used by Cake\Schema package to reflect schema and
* generate schema.
*
* @return \Cake\Database\Schema\SqlserverSchema
*/
public function schemaDialect()
{
return new SqlserverSchema($this);
}
/**
* Returns a SQL snippet for creating a new transaction savepoint
*
* @param string $name save point name
* @return string
*/
public function savePointSQL($name)
{
return 'SAVE TRANSACTION t' . $name;
}
/**
* Returns a SQL snippet for releasing a previously created save point
*
* @param string $name save point name
* @return string
*/
public function releaseSavePointSQL($name)
{
return 'COMMIT TRANSACTION t' . $name;
}
/**
* Returns a SQL snippet for rollbacking a previously created save point
*
* @param string $name save point name
* @return string
*/
public function rollbackSavePointSQL($name)
{
return 'ROLLBACK TRANSACTION t' . $name;
}
/**
* {@inheritDoc}
*
* @return \Cake\Database\SqlserverCompiler
*/
public function newCompiler()
{
return new SqlserverCompiler();
}
/**
* {@inheritDoc}
*/
public function disableForeignKeySQL()
{
return 'EXEC sp_msforeachtable "ALTER TABLE ? NOCHECK CONSTRAINT all"';
}
/**
* {@inheritDoc}
*/
public function enableForeignKeySQL()
{
return 'EXEC sp_msforeachtable "ALTER TABLE ? WITH CHECK CHECK CONSTRAINT all"';
}
}