Document how to access two independent databases

[fatuhoku]

I'm using Express to build an application that accesses two Postgres databases. However it's not clear from documentation whether this is possible with the middleware.

[dresende]

It's not. But probably you want to connect to both databases, define models in both and access them without needing to know where the model was defined, right?

[fatuhoku]

Possibly. I believe Django has what's called 'database routers' which allow the user to define multiple databases, as well as read/write permissions for each of them. One of the databases in my use case, for instance, is to be accessed read-only, and it'd be nice if node-orm2 could enforce that.

[dresende]

That's another cool feature that should be available even outside the middleware. I'm going to try to change the express middleware to support several connections. About the read-only option maybe it fits better on model definition.

[dresende]

This change is not backwards compliant, although I still can try to change to be. Usage:

app.use(orm.express("mysql://...", {
    define: function (db, models) {
        models.Model1 = db.define("model1", { ... });
    }
});
app.use(orm.express("pg://...", {
    define: function (db, models) {
        models.Model2 = db.define("model2", { ... });
    }
});
app.get("/", function (req, res) {
    // if connections are established:
    // req.db should be an Array with both connections (order chan change from definition)
    // req.models should have Model1 and Model2
});

req.db has 3 possible types:

• null before any successful connection is made;
• Object (the db) if only one successful connection is made;
• Array (of dbs) if more than one successful connection is made.