Multiple database support

you can store and retrieve Entities in multiple databases on either a single server or multiple servers. the only requirement is to have unique names for each database. the following example demonstrates how to use multiple databases.

Usage example:

use the DB.DatabaseFor<T>() method to specify which database you want the Entities of a given type to be stored in. it is only neccessary to do that for the entities you want to store in a non-default database. the default database is the very first database your application initializes. all entities by default are stored in the default database unless specified otherwise using DatabaseFor.

as such, the Book entities will be stored in the "BookShop" database and the Picture entities are stored in the "BookShopFILES" database considering the following code.

await DB.InitAsync("BookShop");
await DB.InitAsync("BookShopFILES");

DB.DatabaseFor<Picture>("BookShopFILES");

var book = new Book { Title = "Power Of Now" };
await book.SaveAsync();
//alternative:
//// await DB.SaveAsync(book);

var pic = new Picture
{
    BookID = book.ID,
    Name = "Power Of Now Cover Photo"
};

await pic.SaveAsync();
//alternative:
//// await DB.SaveAsync(pic);

await DB.Update<Picture>()
        .Match(p => p.ID == pic.ID)
        .Modify(p => p.Name, "Updated Cover Photo")
        .ExecuteAsync();

var result = await DB.Find<Picture>().OneAsync(pic.ID);                    

Note

an entity type is tied to a specific database by calling the DatabaseFor method with the database name on startup. that entity type will always be stored in and retrieved from that specific database only. it is not possible to save a single entity type in multiple databases.

if you prefer to keep your database specifications inside the entity classes themselves, you could even call DatabaseFor in the static constructor like so:

public class Picture : Entity
{
    static Picture() => DB.DatabaseFor<Picture>("BookShopFILES");
}

Limitations

• cross-database relationships with Many<T> is not supported.
• no cross-database joins/ look-ups as the driver doesn't support it.
• storing a single entity type in multiple datbases is not supported.