How do auto add datetime in InstallSchema magento2?

Question

in InstallSchema

        ->addColumn(
            'created_at',
            \Magento\Framework\DB\Ddl\Table::TYPE_TIMESTAMP,
            [],
            'Creation Time'
        )
        ->addColumn(
            'updated_at',
            \Magento\Framework\DB\Ddl\Table::TYPE_TIMESTAMP,
            [],
            'Update Time'
        )          

so how do updated_at, create_at auto add datetime when execute action?

Answer 1

Answer provided by @Smartie should work, but you can also achieve this on database level like Magento 2 does for customer entity:

    )->addColumn(
        'created_at',
        \Magento\Framework\DB\Ddl\Table::TYPE_TIMESTAMP,
        null,
        ['nullable' => false, 'default' => \Magento\Framework\DB\Ddl\Table::TIMESTAMP_INIT],
        'Created At'
    )->addColumn(
        'updated_at',
        \Magento\Framework\DB\Ddl\Table::TYPE_TIMESTAMP,
        null,
        ['nullable' => false, 'default' => \Magento\Framework\DB\Ddl\Table::TIMESTAMP_INIT_UPDATE],
        'Updated At'

This will set following columns:

`created_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT 'Created At',
`updated_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT 'Updated At',

Answer 2

You need add "default" option with value \Magento\Framework\DB\Ddl\Table::TIMESTAMP_INIT

->addColumn(
    'created_at',
    \Magento\Framework\DB\Ddl\Table::TYPE_TIMESTAMP,
    null,
    [
        'nullable' => false, 
        'default' => \Magento\Framework\DB\Ddl\Table::TIMESTAMP_INIT
    ],
    'Created At'
)

Answer 3

They are done within the models themselves. For example, when the wishlist model is saved the updated_at is updated in the beforeSave function.

app/code/Magento/Wishlist/Model/Wishlist.php around line 252

 /**
 * Set date of last update for wishlist
 *
 * @return $this
 */
public function beforeSave()
{
    parent::beforeSave();
    $this->setUpdatedAt($this->_date->gmtDate());
    return $this;
}

You can also see something similar in the wishlist item model

app/code/Magento/Wishlist/Model/Item.php

...
public function beforeSave()
{
    ...
    // set current date if added at data is not defined
    if (is_null($this->getAddedAt())) {
        $this->setAddedAt($this->_date->gmtDate());
    }
    ...
}
...