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migration guide improved

tags/2.0.0-beta
Mark 11 years ago
parent
commit
100f582611
  1. 66
      docs/guide/migration.md

66
docs/guide/migration.md

@ -73,21 +73,25 @@ method returns `false` to indicate that the migration cannot be reverted.
As an example, let's show the migration about creating a news table. As an example, let's show the migration about creating a news table.
```php ```php
use yii\db\Schema;
class m101129_185401_create_news_table extends \yii\db\Migration class m101129_185401_create_news_table extends \yii\db\Migration
{ {
public function up() public function up()
{ {
$this->db->createCommand()->createTable('tbl_news', [ $this->createTable('tbl_news', [
'id' => 'pk', 'id' => 'pk',
'title' => 'string(128) NOT NULL', 'title' => Schema::TYPE_STRING . ' NOT NULL',
'content' => 'text', 'content' => Schema::TYPE_TEXT,
])->execute(); ]);
} }
public function down() public function down()
{ {
$this->db->createCommand()->dropTable('tbl_news')->execute(); $this->dropTable('tbl_news');
} }
} }
``` ```
@ -110,38 +114,40 @@ Transactional Migrations
While performing complex DB migrations, we usually want to make sure that each While performing complex DB migrations, we usually want to make sure that each
migration succeed or fail as a whole so that the database maintains the migration succeed or fail as a whole so that the database maintains the
consistency and integrity. In order to achieve this goal, we can exploit consistency and integrity. In order to achieve this goal, we can exploit
DB transactions. DB transactions. We could use special methods `safeUp` and `safeDown` for these purposes.
We could explicitly start a DB transaction and enclose the rest of the DB-related
code within the transaction, like the following:
```php ```php
use yii\db\Schema;
class m101129_185401_create_news_table extends \yii\db\Migration class m101129_185401_create_news_table extends \yii\db\Migration
{ {
public function up() public function safeUp()
{
$transaction=$this->getDbConnection()->beginTransaction();
try
{ {
$this->db->createCommand()->createTable('tbl_news', [ $this->createTable('tbl_news', [
'id' => 'pk',
'title' => Schema::TYPE_STRING . ' NOT NULL',
'content' => Schema::TYPE_TEXT,
]);
$this->createTable('tbl_user', [
'id' => 'pk', 'id' => 'pk',
'title' => 'string NOT NULL', 'login' => Schema::TYPE_STRING . ' NOT NULL',
'content' => 'text', 'password' => Schema::TYPE_STRING . ' NOT NULL',
])->execute(); ]);
$transaction->commit();
} }
catch(Exception $e)
public function safeDown()
{ {
echo "Exception: ".$e->getMessage()."\n"; $this->dropTable('tbl_news);
$transaction->rollback(); $this->dropTable('tbl_user');
return false;
}
} }
// ...similar code for down()
} }
``` ```
When your code uses more then one query it is recommended to use `safeUp` and `safeDown`.
> Note: Not all DBMS support transactions. And some DB queries cannot be put > Note: Not all DBMS support transactions. And some DB queries cannot be put
> into a transaction. In this case, you will have to implement `up()` and > into a transaction. In this case, you will have to implement `up()` and
> `down()`, instead. And for MySQL, some SQL statements may cause > `down()`, instead. And for MySQL, some SQL statements may cause
@ -301,7 +307,7 @@ are located within the module's `migrations` directory, we can use the following
command: command:
``` ```
yii migrate/up --migrationPath=ext.forum.migrations yii migrate/up --migrationPath=@app.modules.forum.migrations
``` ```
@ -314,8 +320,14 @@ or we may want to use a customized migration template. We can do so by modifying
the console application's configuration file like the following, the console application's configuration file like the following,
```php ```php
TBD 'controllerMap' => [
'migrate' => [
'class' => 'yii\console\MigrateController',
'migrationTable' => 'my_custom_migrate_table',
],
]
``` ```
Now if we run the `migrate` command, the above configurations will take effect Now if we run the `migrate` command, the above configurations will take effect
without requiring us to enter the command line options every time. without requiring us to enter the command line options every time. Other command options
can be also configured this way.

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