Magento : How to Check if Mysql Column Exists?

Question

I want to prevent error that column in database table exits.

How can I add column to table only if column does not exist?

Answer 1

You can use this to check if table column exists.

$installer = $this;
$installer->startSetup();

$connection = $installer->getConnection();

$tableName = $installer->getTable('your_table_name');
$columnName = 'testcolumn';

if ($connection->tableColumnExists($tableName, $columnName) === false) {
    $connection->addColumn($tableName, $columnName, array(
        'type'      => Varien_Db_Ddl_Table::TYPE_TEXT,
        'nullable'  => false,
        'length'    => 255,
        'after'     => null, // column name to insert new column after
        'comment'   => 'Title'
    ));  
}