diff --git a/framework/yii/db/Command.php b/framework/yii/db/Command.php
index 4b5dfc5..1564b50 100644
--- a/framework/yii/db/Command.php
+++ b/framework/yii/db/Command.php
@@ -661,7 +661,7 @@ class Command extends \yii\base\Component
 	 * @param string|array $columns comma separated string or array of columns that the primary key will consist of.
 	 * @return Command the command object itself.
 	 */	
-	public function addPrimaryKey($name,$table,$columns)
+	public function addPrimaryKey($name, $table, $columns)
 	{
 		$sql = $this->db->getQueryBuilder()->addPrimaryKey($name, $table, $columns);
 		return $this->setSql($sql);
@@ -673,7 +673,7 @@ class Command extends \yii\base\Component
 	 * @param string $table the table that the primary key constraint will be removed from.
 	 * @return Command the command object itself
 	 */	
-	public function dropPrimarykey($name,$table)
+	public function dropPrimarykey($name, $table)
 	{
 		$sql = $this->db->getQueryBuilder()->dropPrimarykey($name, $table);
 		return $this->setSql($sql);
diff --git a/framework/yii/db/QueryBuilder.php b/framework/yii/db/QueryBuilder.php
index aab7d3e..4d7a451 100644
--- a/framework/yii/db/QueryBuilder.php
+++ b/framework/yii/db/QueryBuilder.php
@@ -276,12 +276,16 @@ class QueryBuilder extends \yii\base\Object
 	 * @param string|array $columns comma separated string or array of columns that the primary key will consist of.
 	 * @return string the SQL statement for adding a primary key constraint to an existing table.
 	 */
-	public function addPrimaryKey($name,$table,$columns)
+	public function addPrimaryKey($name, $table, $columns)
 	{
-		if(is_string($columns))
+		if (is_string($columns)) {
 			$columns=preg_split('/\s*,\s*/',$columns,-1,PREG_SPLIT_NO_EMPTY);
-		foreach($columns as $i=>$col)
+		}
+		
+		foreach ($columns as $i=>$col) {
 			$columns[$i]=$this->db->quoteColumnName($col);
+		}
+		
 		return 'ALTER TABLE ' . $this->db->quoteTableName($table) . ' ADD CONSTRAINT '
 			. $this->db->quoteColumnName($name) . '  PRIMARY KEY ('
 			. implode(', ', $columns). ' )';
@@ -293,7 +297,7 @@ class QueryBuilder extends \yii\base\Object
 	 * @param string $table the table that the primary key constraint will be removed from.
 	 * @return string the SQL statement for removing a primary key constraint from an existing table.	 *
 	 */
-	public function dropPrimarykey($name,$table)
+	public function dropPrimarykey($name, $table)
 	{
 		return 'ALTER TABLE ' . $this->db->quoteTableName($table)
 			. ' DROP CONSTRAINT ' . $this->db->quoteColumnName($name);
diff --git a/framework/yii/db/mysql/QueryBuilder.php b/framework/yii/db/mysql/QueryBuilder.php
index 5d3ee57..e785bae 100644
--- a/framework/yii/db/mysql/QueryBuilder.php
+++ b/framework/yii/db/mysql/QueryBuilder.php
@@ -94,7 +94,7 @@ class QueryBuilder extends \yii\db\QueryBuilder
 	 * @param string $table the table that the primary key constraint will be removed from.
 	 * @return string the SQL statement for removing a primary key constraint from an existing table.	 *
 	 */
-	public function dropPrimarykey($name,$table)
+	public function dropPrimarykey($name, $table)
 	{
 		return 'ALTER TABLE ' . $this->db->quoteTableName($table) . ' DROP PRIMARY KEY';		
 	}
diff --git a/framework/yii/db/sqlite/QueryBuilder.php b/framework/yii/db/sqlite/QueryBuilder.php
index a3f3f2a..01f5691 100644
--- a/framework/yii/db/sqlite/QueryBuilder.php
+++ b/framework/yii/db/sqlite/QueryBuilder.php
@@ -188,7 +188,7 @@ class QueryBuilder extends \yii\db\QueryBuilder
 	 * @return string the SQL statement for adding a primary key constraint to an existing table.
 	 * @throws NotSupportedException this is not supported by SQLite
 	 */
-	public function addPrimaryKey($name,$table,$columns)
+	public function addPrimaryKey($name, $table, $columns)
 	{
 		throw new NotSupportedException(__METHOD__ . ' is not supported by SQLite.');
 	}	
@@ -200,7 +200,7 @@ class QueryBuilder extends \yii\db\QueryBuilder
 	 * @return string the SQL statement for removing a primary key constraint from an existing table.
 	 * @throws NotSupportedException this is not supported by SQLite	 *
 	 */
-	public function dropPrimarykey($name,$table)
+	public function dropPrimarykey($name, $table)
 	{
 		throw new NotSupportedException(__METHOD__ . ' is not supported by SQLite.');		
 	}