Fixes #3399: Added support for MS SQL Server older than 2012

framework/CHANGELOG.md

@@ -63,6 +63,7 @@ Yii Framework 2 Change Log
 - Enh #3298: Supported configuring `View::theme` using a class name (netyum, qiangxue)
 - Enh #3328: `BaseMailer` generates better text body from html body (armab)
 - Enh #3380: Allow `value` in `defaultValueValidator` to be a closure (Alex-Code)
+- Enh #3399: Added support for MS SQL Server older than 2012 (fourteenmeister, samdark)
 - Enh #3472: Added configurable option to encode spaces in dropDownLists and listBoxes (kartik-v)
 - Enh #3518: `yii\helpers\Html::encode()` now replaces invalid code sequences with "�" (DaSourcerer)
 - Enh #3520: Added `unlinkAll()`-method to active record to remove all records of a model relation (NmDimas, samdark, cebe)

framework/db/mssql/QueryBuilder.php

@@ -140,15 +140,22 @@ class QueryBuilder extends \yii\db\QueryBuilder
         return "ALTER TABLE {$table} {$enable} CONSTRAINT ALL";
     }
 
+    /**
+     * @inheritdoc
+     */
     public function buildOrderBy($columns)
     {
         if (empty($columns)) {
-            return 'ORDER BY (SELECT NULL)'; // hack so limit will work if no order by is specified
+            // hack so LIMIT will work if no ORDER BY is specified
+            return 'ORDER BY (SELECT NULL)';
         } else {
             return parent::buildOrderBy($columns);
         }
     }
 
+    /**
+     * @inheritdoc
+     */
     public function build($query, $params = [])
     {
         $query->prepareBuild($this);
@@ -163,31 +170,48 @@ class QueryBuilder extends \yii\db\QueryBuilder
             $this->buildGroupBy($query->groupBy),
             $this->buildHaving($query->having, $params),
             $this->buildOrderBy($query->orderBy),
-            $this->olderMssql() ? '' : $this->buildLimit($query->limit, $query->offset),
+            $this->isOldMssql() ? '' : $this->buildLimit($query->limit, $query->offset),
         ];
 
         $sql = implode($this->separator, array_filter($clauses));
-        if ($this->olderMssql())
-            $sql = $this->applyLimit($sql, $query);
+        if ($this->isOldMssql()) {
+            $sql = $this->applyLimitAndOffset($sql, $query);
+        }
         $union = $this->buildUnion($query->union, $params);
         if ($union !== '') {
             $sql = "($sql){$this->separator}$union";
         }
 
-
         return [$sql, $params];
     }
 
-    public function applyLimit($sql, $query)
+    /**
+     * Applies limit and offset to SQL query
+     *
+     * @param string $sql SQL query
+     * @param \yii\db\ActiveQuery $query the [[Query]] object from which the SQL statement generated
+     * @return string resulting SQL
+     */
+    private function applyLimitAndOffset($sql, $query)
     {
         $limit = $query->limit !== null ? (int)$query->limit : -1;
         $offset = $query->offset !== null ? (int)$query->offset : -1;
-        if ($limit > 0 || $offset >= 0)
+        if ($limit > 0 || $offset >= 0) {
             $sql = $this->rewriteLimitOffsetSql($sql, $limit, $offset, $query);
+        }
         return $sql;
     }
 
-    protected function rewriteLimitOffsetSql($sql, $limit, $offset, $query)
+    /**
+     * Rewrites limit and offset in SQL query
+     *
+     * @param string $sql SQL query
+     * @param integer $limit
+     * @param integer $offset
+     * @param \yii\db\ActiveQuery $query the [[Query]] object from which the SQL statement generated
+     * @return string resulting SQL query
+     */
+    private function rewriteLimitOffsetSql($sql, $limit, $offset, $query)
     {
         $originalOrdering = $this->buildOrderBy($query->orderBy);
         if ($query->select) {
@@ -198,29 +222,42 @@ class QueryBuilder extends \yii\db\QueryBuilder
         }
         if ($select === '*') {
             $columns = $this->getAllColumnNames($query->modelClass);
-            if ($columns && is_array($columns))
+            if ($columns && is_array($columns)) {
                 $select = implode(', ', $columns);
-            else
+            } else {
                 $select = $columns;
             }
+        }
         $sql = str_replace($originalOrdering, '', $sql);
         $sql = preg_replace('/^([\s(])*SELECT( DISTINCT)?(?!\s*TOP\s*\()/i', "\\1SELECT\\2 rowNum = ROW_NUMBER() over ({$originalOrdering}),", $sql);
         $sql = "SELECT TOP {$limit} {$select} FROM ($sql) sub WHERE rowNum > {$offset}";
         return $sql;
     }
 
+    /**
+     * Returns an array of column names given model name
+     *
+     * @param string $modelClass name of the model class
+     * @return array|null array of column names
+     */
     protected function getAllColumnNames($modelClass = null)
     {
         if (!$modelClass) {
             return null;
         }
+        /** @var \yii\db\ActiveRecord $model */
         $model = new $modelClass;
         $schema = $model->getTableSchema();
         $columns = array_keys($schema->columns);
         return $columns;
     }
 
-    protected function olderMssql()
+    /**
+     * @return boolean if MSSQL used is old
+     * @throws \yii\base\InvalidConfigException
+     * @throws \yii\db\Exception
+     */
+    protected function isOldMssql()
     {
         $this->db->open();
         $version = preg_split("/\./", $this->db->pdo->getAttribute(\PDO::ATTR_SERVER_VERSION));