DemacMedia/Magento-Multi-Location-Inventory

<?php
/** @var Mage_Core_Model_Resource_Setup $installer */
$installer = $this;

$installer->startSetup();

/**
 * Add "code" column for use when importing/exporting stock data
 */
$table      = $installer->getTable('demac_multilocationinventory/location');
$connection = $installer->getConnection();

$connection->addColumn($table, 'code',
    array(
        'type'    => Varien_Db_Ddl_Table::TYPE_TEXT,
        'length'  => 255,
        'unique'  => true,
        'comment' => 'Location code for import',
        'after'   => 'name'
    )
);

$connection->addIndex($table, 'IDX_CODE', 'code', Varien_Db_Adapter_Interface::INDEX_TYPE_UNIQUE);

$installer->endSetup();