Resolves issue #2081 : provides an option to include statements to disable and re-enable foreign key checks in a MySQL database backup output statement.

4 files changed, 42 insertions, 14 deletions

diff --git a/system/database/DB_utility.php b/system/database/DB_utility.php
index c4140aef3..3ed75967e 100644
--- a/system/database/DB_utility.php
+++ b/system/database/DB_utility.php
@@ -326,7 +326,8 @@ abstract class CI_DB_utility {
 				'format'		=> 'gzip', // gzip, zip, txt
 				'add_drop'		=> TRUE,
 				'add_insert'		=> TRUE,
-				'newline'		=> "\n"
+				'newline'		=> "\n",
+				'fk_checks'		=> TRUE
 			);
 
 		// Did the user submit any preferences? If so set them....
diff --git a/system/database/drivers/mysql/mysql_utility.php b/system/database/drivers/mysql/mysql_utility.php
index 8aa051755..e2de82d0b 100644
--- a/system/database/drivers/mysql/mysql_utility.php
+++ b/system/database/drivers/mysql/mysql_utility.php
@@ -76,6 +76,13 @@ class CI_DB_mysql_utility extends CI_DB_utility {
 
 		// Build the output
 		$output = '';
+
+		// Do we need to include a statement to disable FK checks?
+		if ($fk_checks === FALSE)
+		{
+			$output .= "SET foreign_key_checks = 0;".$newline;
+		}
+
 		foreach ( (array) $tables as $table)
 		{
 			// Is the table in the "ignore" list?
@@ -181,6 +188,12 @@ class CI_DB_mysql_utility extends CI_DB_utility {
 			$output .= $newline.$newline;
 		}
 
+		// Do we need to include a statement to re-enable FK checks?
+		if ($fk_checks === FALSE)
+		{
+			$output .= "SET foreign_key_checks = 1;".$newline;
+		}
+
 		return $output;
 	}
 
diff --git a/system/database/drivers/mysqli/mysqli_utility.php b/system/database/drivers/mysqli/mysqli_utility.php
index 345691e84..ff4949046 100644
--- a/system/database/drivers/mysqli/mysqli_utility.php
+++ b/system/database/drivers/mysqli/mysqli_utility.php
@@ -76,6 +76,13 @@ class CI_DB_mysqli_utility extends CI_DB_utility {
 
 		// Build the output
 		$output = '';
+
+		// Do we need to include a statement to disable FK checks?
+		if ($fk_checks === FALSE)
+		{
+			$output .= "SET foreign_key_checks = 0;".$newline;
+		}
+
 		foreach ( (array) $tables as $table)
 		{
 			// Is the table in the "ignore" list?
@@ -181,6 +188,12 @@ class CI_DB_mysqli_utility extends CI_DB_utility {
 			$output .= $newline.$newline;
 		}
 
+		// Do we need to include a statement to re-enable FK checks?
+		if ($fk_checks === FALSE)
+		{
+			$output .= "SET foreign_key_checks = 1;".$newline;
+		}
+
 		return $output;
 	}
 
diff --git a/user_guide_src/source/database/utilities.rst b/user_guide_src/source/database/utilities.rst
index 06ecb2da1..1631066fe 100644
--- a/user_guide_src/source/database/utilities.rst
+++ b/user_guide_src/source/database/utilities.rst
@@ -45,7 +45,7 @@ $this->dbutil->list_databases();
 Returns an array of database names::
 
 	$dbs = $this->dbutil->list_databases();
-	
+
 	foreach ($dbs as $db)
 	{
  		echo $db;
@@ -102,7 +102,7 @@ FALSE on failure.
 ::
 
 	$result = $this->dbutil->optimize_database();
-	
+
 	if ($result !== FALSE)
 	{
 		print_r($result);
@@ -119,9 +119,9 @@ parameter of the method must contain the result object from your
 query. Example::
 
 	$this->load->dbutil();
-	
+
 	$query = $this->db->query("SELECT * FROM mytable");
-	
+
 	echo $this->dbutil->csv_from_result($query);
 
 The second, third, and fourth parameters allow you to set the delimiter
@@ -147,16 +147,16 @@ parameter expects a query result object, the second may contain an
 optional array of config parameters. Example::
 
 	$this->load->dbutil();
-	
+
 	$query = $this->db->query("SELECT * FROM mytable");
-	
+
 	$config = array (
 		'root'		=> 'root',
 		'element'	=> 'element',
 		'newline'	=> "\n",
-		'tab'		=> "\t" 
+		'tab'		=> "\t"
 	);
-	
+
 	echo $this->dbutil->xml_from_result($query, $config);
 
 .. important:: This method will NOT write the XML file for you. It
@@ -172,7 +172,7 @@ backup data can be compressed in either Zip or Gzip format.
 .. note:: This feature is only available for MySQL and Interbase/Firebird databases.
 
 .. note:: For Interbase/Firebird databases, the backup file name is the only parameter.
-	
+
 		Eg. $this->dbutil->backup('db_backup_filename');
 
 .. note:: Due to the limited execution time and memory available to PHP,
@@ -188,14 +188,14 @@ Usage Example
 
 	// Load the DB utility class
 	$this->load->dbutil();
-	
+
 	// Backup your entire database and assign it to a variable
 	$backup =& $this->dbutil->backup();
-	
+
 	// Load the file helper and write the file to your server
 	$this->load->helper('file');
 	write_file('/path/to/mybackup.gz', $backup);
-	
+
 	// Load the download helper and send the file to your desktop
 	$this->load->helper('download');
 	force_download('mybackup.gz', $backup);
@@ -215,7 +215,7 @@ parameter of the ``backup()`` method. Example::
 		'add_insert'	=> TRUE,			// Whether to add INSERT data to backup file
 		'newline'	=> "\n"				// Newline character used in backup file
 	);
-	
+
 	$this->dbutil->backup($prefs);
 
 Description of Backup Preferences
@@ -233,4 +233,5 @@ Preference      Default Value           Options                 Description
 **add_drop**    TRUE                    TRUE/FALSE              Whether to include DROP TABLE statements in your SQL export file.
 **add_insert**  TRUE                    TRUE/FALSE              Whether to include INSERT statements in your SQL export file.
 **newline**     "\\n"                   "\\n", "\\r", "\\r\\n"  Type of newline to use in your SQL export file.
+**fk_checks**   TRUE                    TRUE/FALSE              Whether output should keep foreign key checks enabled.
 =============== ======================= ======================= ========================================================================
\ No newline at end of file