PHP & MySQL: Truncate multiple tables

问题:

I tried to truncate a table but why is it not working? must something wrong in the database query?

$sql = "TRUNCATE TABLE `table_name`";

$result = $connection -> query($sql);

Ideally, I want to truncate all tables in one go - is it possible?

if you wonder what is inside the class that I use to make the database queries, here is it,

#connects the database and handling the result
class __database {

 protected $connection = null;
 protected $error = null;

 #make a connection
 public function __construct($hostname,$username,$password,$database)
 {
  $this -> connection = new mysqli($hostname,$username,$password,$database);

  if (mysqli_connect_errno()) 
  {
   printf("Connect failed: %s\n", mysqli_connect_error());
   exit();
  }
 }

 ...

 #performs a query on the database
 public function query($query)
 {
  $result = $this -> connection -> query($query); 
  if($result) 
  {
   return $result;
  } 
  else
  {
   $this -> error = $this -> connection -> error;
   return false;
  }

 }


 #display error
 public function get_error() 
 {
  return $this -> error;
 }

 #closes the database connection when object is destroyed.
    public function __destruct()
    {
        $this -> connection -> close();
    }
}

thanks.

edit:

below is how I call the db object,

# the host used to access DB
define('DB_HOST', 'localhost');

# the username used to access DB
define('DB_USER', 'root');

# the password for the username
define('DB_PASS', 'xxx');

# the name of your databse 
define('DB_NAME', 'xxx'); 

$connection = new __database(DB_HOST,DB_USER,DB_PASS,DB_NAME);

回答1:

By the MySQL Reference Manual

http://dev.mysql.com/doc/refman/5.0/en/truncate-table.html

You can only delete one table at a time using TRUNCATE.

You could try executing multiple queries in one PHP query by using a ";" delimiter between them.

回答2:

thanks for the help guys! here is my answer,

# truncate data from all table
# $sql = "SHOW TABLES IN 1hundred_2011";
# or,
$sql = "SELECT * FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA LIKE '".DB_NAME."'";

# use the instantiated db connection object from the init.php, to process the query
$tables = $connection -> fetch_all($sql);
//print_r($tables);

foreach($tables as $table) 
{
    //echo $table['TABLE_NAME'].'<br/>';

    # truncate data from this table
    # $sql = "TRUNCATE TABLE `developer_configurations_cms`";

    # use the instantiated db connection object from the init.php, to process the query
    # $result = $connection -> query($sql);

    # truncate data from this table
    $sql = "TRUNCATE TABLE `".$table['TABLE_NAME']."`";

    # use the instantiated db connection object from the init.php, to process the query
    $result = $connection -> query($sql);
}

回答3:

You have a couple different option.

• Run a query for each truncate
• Create a stored procedure that will truncate all the tables you want to do.