如何使用JDBC更改架构以连接到Grails中的MySQL？

Question

I'm using a spring bean to interact with SQL in a Grails app. My resources.groovy file looks like this:

beans = {
    groovySql(groovy.sql.Sql, ref('dataSource')) {}
}

My DataSource.groovy file has a data source set up (and named dataSource ).

The JDBC connection string that I had been using looked something like this:

jdbc:mysql://my.domain.com/Schema_Number_One

And when I had it like that, everything worked fine. However, I now need to use more than just the one schema on that server. So I changed my connection string to simply this:

jdbc:mysql://my.domain.com/

I figured this would be fine, and that I could just issue a query like USE Schema_Number_Two to switch. But something's gone awry.

When I try to run this code:

def query = "USE Schema_Number_Two"
groovySql.execute(query)
groovySql.commit()

I get the following error in the console:

Connection is read-only. Queries leading to data modification are not allowed.

So... apparently it sees the USE statement as a write query? My next thought was to try to trick it into thinking it was a read-only statement by doing this:

def query = "USE Schema_Number_Two; SELECT 1"
groovySql.execute(query)
groovySql.commit()

And while that query does execute without error, it doesn't stick. The very next query returned some error message indicating no database had been specified.

I've also tried adding @Transactional(readOnly=false) just before the method I'm calling here in my controller, but that doesn't seem to have any impact. And I can confirm that I'm using the Grails Transactional annotation.

Answer 1

As far as I could tell, there was no way to accomplish what I was trying to do here. What I ended up having to do was simply to define separate data sources.