Grails 2 - How to dynamically call multiple datasources

Question

I have two named data sources in my Grails app (Grails 2.0.3)...

dataSource_a {
   // ...
}

dataSource_b {
   // ...
}

I'd like the ability to dynamically change what datasource I'm accessing, based on some kind of parameter. I could do something like this...

def findPeople(datasource) {
    if (datasource == 'a') {
        return Person.a.list()
    } else if (datasource == 'b') {
        return Person.b.list()
    }
}

What I was really hoping to be able to do, though, is something like this...

def findPeople(datasource) {
    return Person."$datasource".list()
}

Unfortunately, I get an error when I try and do that. "Fatal error occurred apply query transformations: null 1 error".

Any thoughts on how to accomplish this? Or am I just stuck with if/switch blocks?

Update: I found that it works if you don't inject a variable into the string. So, Person."a".list() works. Doesn't really help me, but interesting nonetheless. — jckeyes, May 10 '12 at 12:46
if you did want the variable for some reason, it would "${datasource}" instead of "$datasource". — GreyBeardedGeek, May 10 '12 at 12:56
Actually, you can do simple variable injections in Groovy without the {}... however I get the same result if I do "${datasource}" — jckeyes, May 10 '12 at 12:58

score 4 · Accepted Answer · answered May 10 '12 at 15:10

4

I figured it out, this is how you have to do it.

def findPeople(datasource) {
    def p = People.class
    p."${datasource}".list()
}

For some reason, if you call it like that, it works.

answered May 10 '12 at 15:10

jckeyes

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This is extremely odd, but it works. Did you ever figure out how to get it work with a ORM object instance? Like `people."${datasource}".save()` – James McMahon Sep 19 '13 at 17:42
1

Actually it works fine with instance objects is the object isn't strongly typed, ie `def a = ` vs `People a = ` – James McMahon Sep 19 '13 at 19:24
I am facing same issue . When I am trying people."${datasource}".save() it say Fatal error occurred applying query transformations: null – user9873999 Feb 06 '14 at 10:09
Can you anyone suggest how I can execute save on existing method. – user9873999 Feb 06 '14 at 10:10
Have anyone manage to fix this? I need to save in a specific datasource but it says missingpropertyexception def p = new Nxtt_reports() p."dominio2".save() – John Gamarra González Mar 16 '16 at 03:50
How can we access the default (unnamed) data source in this way? – Behlül Oct 05 '19 at 23:45

Grails 2 - How to dynamically call multiple datasources

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