Fixes #4342

framework/CHANGELOG.md

@@ -68,6 +68,7 @@ Yii Framework 2 Change Log
 - Bug #4162: Fixed bug where schema name was not used in ’SHOW CREATE TABLE’ query in `yii\db\mysql\Schema` (stevekr)
 - Bug #4241: `yii\widgets\Pjax` was incorrectly setting container id (mitalcoi)
 - Bug #4276: Added check for UPLOAD_ERR_NO_FILE in `yii\web\UploadedFile` and return null if no file was uploaded (OmgDef)
+- Bug #4342: mssql (dblib) driver does not support getting attributes (tof06)
 - Bug: Fixed inconsistent return of `\yii\console\Application::runAction()` (samdark)
 - Bug: URL encoding for the route parameter added to `\yii\web\UrlManager` (klimov-paul)
 - Bug: Fixed the bug that requesting protected or private action methods would cause 500 error instead of 404 (qiangxue)

framework/db/mssql/PDO.php

@@ -61,4 +61,23 @@ class PDO extends \PDO
 
         return true;
     }
+
+    /**
+     * Retrieve a database connection attribute.
+     * It is necessary to override PDO's method as some MSSQL PDO driver (e.g. dblib) does not
+     * support getting attributes
+     */
+    public function getAttribute($attribute)
+    {
+        try {
+            return parent::getAttribute($attribute);
+        } catch (\PDOException $e) {
+            switch ($attribute) {
+                case PDO::ATTR_SERVER_VERSION:
+                    return $this->query("SELECT SERVERPROPERTY('productversion')")->fetchColumn();
+                default:
+                    throw $e;
+            }
+        }
+    }
 }

framework/db/mssql/QueryBuilder.php

@@ -17,6 +17,8 @@ use yii\base\InvalidParamException;
  */
 class QueryBuilder extends \yii\db\QueryBuilder
 {
+    protected $_oldMssql;
+
     /**
      * @var array mapping from abstract column types (keys) to physical column types (values).
      */
@@ -189,8 +191,7 @@ class QueryBuilder extends \yii\db\QueryBuilder
         $originalOrdering = $this->buildOrderBy($query->orderBy);
         if ($query->select) {
             $select = implode(', ', $query->select);
-        }
-        else {
+        } else {
             $select = $query->select = '*';
         }
         if ($select === '*') {
@@ -238,8 +239,11 @@ class QueryBuilder extends \yii\db\QueryBuilder
      */
     protected function isOldMssql()
     {
-        $pdo = $this->db->getSlavePdo();
-        $version = preg_split("/\./", $pdo->getAttribute(\PDO::ATTR_SERVER_VERSION));
-        return $version[0] < 11;
+        if ($this->_oldMssql === null) {
+            $pdo = $this->db->getSlavePdo();
+            $version = preg_split("/\./", $pdo->getAttribute(\PDO::ATTR_SERVER_VERSION));
+            $this->_oldMssql = $version[0] < 11;
+        }
+        return $this->_oldMssql;
     }
 }