How to connect two or more db by boss_db?

[jiale.chan]

Hi,

I have tow mysql db,

How to connect two or more database by boss_db?

[Nicholas Whittier]

Use db_shards in boss config.

....

 {db_shards, [
        [{db_host, "localhost"},
         {db_adapter, pgsql},
         {db_port, 5432},
         {db_username, "pg_user"},
         {db_password, "pg_pass"},
         {db_database, "pg_db"},
         {db_shard_id, shard_pg},
         {db_shard_models, [some_postgres_model,another_postgres_model]}],
        [{db_host, "mysql.example.com"},
         {db_adapter, mysql},
         {db_port, 3306},
         {db_username, "my_user"},
         {db_password, "my_pass"},
         {db_database, "my_db"},
         {db_shard_id, shard_my},
         {db_shard_models, [some_mysql_model,another_mysql_model]}]
...

Note that you can still use the default db setting (mock, via mnesia) to handle sessions and boss-specific db needs.

-- Nicholas

[Alexey Marunin]

Nicholas,

This is just what I need!

Few questions:

1) What for need value of db_shard_id? Only for internal usage in mysql/postgres/... or I should use it explicitly?

2) Can I use "cross-db" models? Something like this:

SiteUser: Id, Name -> db1

ForumUser: Id, SiteUserId -> db2

Is valid call:

user = forum_user:site_user()

среда, 19 марта 2014 г., 21:37:17 UTC+4 пользователь Nicholas Whittier написал:

[Nicholas Whittier]

On Wednesday, March 19, 2014 12:39:52 PM UTC-7, Alexey Marunin wrote:

Nicholas,

This is just what I need!

Few questions:

1) What for need value of db_shard_id? Only for internal usage in mysql/postgres/... or I should use it explicitly?

It must be an atom, and afaik boss_db uses it and you shouldn't need to worry about it.

 

2) Can I use "cross-db" models? Something like this:

Since shards can be different databases (mongo vs. mysql OR mysql1 vs. mysql2), I woudn't think you could relate the models from two different db shards via Boss_DB's relationships. Relationships are managed in the db_adapter and as far as CB knows, each db shard is using it's own adapter. I haven't needed or tried this, maybe someone else can chime in with other suggestions?

 

-- Nicholas