如何使用PDO与Idiorm检查表是否存在

Question

/**
 * Check if a table exists in the current database.
 *
 * @param PDO $pdo PDO instance connected to a database.
 * @param string $table Table to search for.
 * @return bool TRUE if table exists, FALSE if no table found.
 */
function tableExists($pdo, $table) {

    // Try a select statement against the table
    // Run it in try/catch in case PDO is in ERRMODE_EXCEPTION.
    try {
        $result = $pdo->query("SELECT 1 FROM $table LIMIT 1");
    } catch (Exception $e) {
        // We got an exception == table not found
        return FALSE;
    }

    // Result is either boolean FALSE (no table found) or PDOStatement Object (table found)
    return $result !== FALSE;
}

1. How to configure this function with Idiorm PDO?

2. Is it okey to use -

   try {
       $page = ORM::for_table($table)->where('slug', $slug )->find_one();  
   } (catch $e) {
       // 404 with an error that table does not exists.
   }
   

instead of the "tableExists" function?

Answer 1

If I am understanding your question correctly you want to check if a table exists in a MySQL database.

Q. 1

It should be noted that the two queries are not identical. You've got:

$page = ORM::for_table($table)->where('slug', $slug )->find_one();

But your second query should be:

$page = ORM::for_table($table)->select_expr(1)->find_one();

See the result columns documentation for information.

Q. 2

Yes, Idiorm uses PDO underneath so you'll get the same PDO exception - this is something you really could just try and see how it works with:

try {
    $page = ORM::for_table($table)->where('slug', $slug )->find_one();  
} (catch $e) {
    var_dump($e);
}