在 Yii 2.0 中添加了多个 DB 应用组件时，多个数据库迁移的实现

1、在 Yii 2.0 中添加了多个数据库连接组件时

    'components' => [
        'db' => [
            'class' => 'yii\db\Connection',
            'dsn' => 'mysql:host=62.234.135.47;dbname=pcs_api',
            'username' => 'sq_pcs',
            'password' => '',
            'tablePrefix' => 'pa_',
            'charset' => 'utf8mb4',
            'enableSchemaCache' => false,
            'schemaCacheDuration' => 3600,
            'schemaCache' => 'redisCache',
        ],
        'statDb' => [
            'class' => 'yii\db\Connection',
            'dsn' => 'mysql:host=62.234.135.47;dbname=pcs_stat',
            'username' => 'sq_pcs',
            'password' => '',
            'tablePrefix' => 'ps_',
            'charset' => 'utf8mb4',
        ],
    ],

2、迁移多个数据库的策略是把迁移存放到不同的目录下。一个连接组件对应一个目录。db 的目录：/console/migrations/。statDb 的目录：/console/migrations/stat_db/。如图1

3、生成 statDb 下的迁移文件时，需要指定： –migrationPath=@console/migrations/stat_db/ ，如图2

PS E:\wwwroot\pcs-stat> ./yii migrate/create stat_task --migrationPath=@console/migrations/stat_db/
Yii Migration Tool (based on Yii v2.0.31)

Create new migration 'E:\wwwroot\pcs-stat/console/migrations/stat_db/\m200520_064341_stat_task.php'? (yes|no) [no]:yes
New migration created successfully.

4、然后可以通过如下命令分别对不同的数据库进行迁移。第一条命令将会把 /console/migrations/ 目录下的迁移提交到 db 数据库当中， 第二条命令则会把 /console/migrations/stat_db/ 下的迁移提交到 statDb 数据库当中，以此类推。目录的层级仅支持一级。如图3

PS E:\wwwroot\pcs-stat> ./yii migrate
Yii Migration Tool (based on Yii v2.0.31)

No new migrations found. Your system is up-to-date.
PS E:\wwwroot\pcs-stat> ./yii migrate --migrationPath=@console/migrations/stat_db/ --db=statDb
Yii Migration Tool (based on Yii v2.0.31)

Creating migration history table "ps_migration"...Done.
Total 2 new migrations to be applied:
        m200519_065119_stat_task
        m200519_071446_stat_resource

Apply the above migrations? (yes|no) [no]:no
PS E:\wwwroot\pcs-stat> ./yii migrate --migrationPath=@console/migrations/stat_db/ --db=statDb
Yii Migration Tool (based on Yii v2.0.31)

Creating migration history table "ps_migration"...Done.
Total 2 new migrations to be applied:
        m200519_065119_stat_task
        m200519_071446_stat_resource
Apply the above migrations? (yes|no) [no]:yes
*** applying m200519_065119_stat_task
    > create table {{%stat_task}} ... done (time: 0.666s)
    > create unique index uc_group_id_code_ca on {{%stat_task}} (group_id,code,created_at) ... done (time: 0.077s)
*** applied m200519_065119_stat_task (time: 1.016s)

*** applying m200519_071446_stat_resource
    > create table {{%stat_resource}} ... done (time: 0.762s)
    > create unique index uc_group_id_ca on {{%stat_resource}} (group_id,created_at) ... done (time: 0.081s)
*** applied m200519_071446_stat_resource (time: 1.113s)


2 migrations were applied.

Migrated up successfully.

5、查看 statDb 数据库当中的迁移历史记录，符合预期。如图4