Question

I’m using the datasources pluging for Grails described here: http://burtbeckwith.com/blog/?p=70

I’m connecting to 2 MySQL database schemas on the same server: my_schema_1 and my_schema_2. Most of the data I need comes from my_schema_1, but one of its tables contains a column that references one of the tables in my_schema_2.

Here are my datasource definitions in my Datasources.groovy file (simplified):

datasources = {
    datasource(name: 'my_schema_1') {
        domainClasses([Question, Answer])
        driverClassName('com.mysql.jdbc.Driver')
        url('jdbc:mysql://test.myserver.com/my_schema_1')
        username('***')
        password('***')
    }

    datasource(name: 'my_schema_2') {
        domainClasses([Genre])
        driverClassName('com.mysql.jdbc.Driver')
        url('jdbc:mysql://test.myserver.com/my_schema_2')
        username('***')
        password('***')
    }
}

Here are my 3 class definitions:

class Question {
    String text
    Answer answer
    Genre genre
}

class Answer {
    String text
}

class Genre {
    String name
}

Whenever I try to perform a criteria query on the Question class, I get the following mapping exception:

An association from the table question refers to an unmapped class: Genre

If I comment out the genre property in the Question class, everything works fine. If I perform a criteria query on the Genre class itself,
everything works fine. There just seems to be a problem joining the 2 classes across schemas. (Of course, it’s also very possible I missed
something or did something incorrectly.)

Am I doing something wrong or is this a limitation of the datasources plugin? And, if this is a limitation of the plugin, what alternatives could I use to achieve what I need?

Any help/suggestions are much appreciated.

Thanks,

B.J.

Answer 1

I found a simpler solution since the databases are on the same server.

I simply define one datasource as follows (without specifying a database):

datasources = {
    datasource(name: 'my_schemas') {
        domainClasses([Question, Answer, Genre])
        driverClassName('com.mysql.jdbc.Driver')
        url('jdbc:mysql://test.myserver.com')
        username('***')
        password('***')
    }
}

Then I specify the database in my domain classes’ mapping sections:

class Question {
    String text
    Answer answer
    Genre genre

    static mapping = {
        table 'my_schema_1.question'
    }
}

class Answer {
    String text

    static mapping = {
        table 'my_schema_1.answer'
    }
}

class Genre {
    String name

    static mapping = {
        table 'my_schema_2.genre'
    }
}

Again, this only works because the 2 databases are on the same server, and they use the same username/password.