Grails 2.4.4 removing all items from a hasmany String relationship - grails

Question

I have a User class that hasMany organizations, and organizations are String UIDs.
class User implements Serializable {
...
List organizations
static hasMany = [organizations: String]
...
}
To update an User instance, I need to remove all the Strings from "organizations" before adding what the updated uids, but it doesn't work. The same organizations are resaved into the collection after I delete them and save the User instance.
I tried many ways:
// 1
user.organizations.clear()
// 2
def orgsToDelete = [] // this is to avoid concurrent modification exception
orgsToDelete += user.organizations
orgsToDelete.each { orguid ->
user.removeFromOrganizations(orguid)
}
After any of 1 or 2, the user.organizations is empty, but when I do:
user.save(flush:true)
I get the same organizations that where before the clear/removeFromOrganizations
I can't do user.organizations.each { it.delete() } because the items are not domain classes but Strings.
Another weird thing is I have a custom validator to check if the collection has any items, and it seems it doesn't gets any errors, event the organizations is empty, this is my validator:
organizations validator: { val, obj ->
if (obj.organizations.size() == 0) return false
return true
}
When I do this on the controller update action, it says hasErrors() == false
if (userInstance.hasErrors())
{
println "has errors"
respond userInstance.errors, view:'edit'
return
}
Any ideas?
Here is the controller: https://github.com/ppazos/cabolabs-ehrserver/blob/master/grails-app/controllers/com/cabolabs/security/UserController.groovy#L199-L237

Answer 1

Use your own domain class instead of String as collection's elements, like:
class Organization {
String name
static belongsTo = [ User ]
}
then you should be able to properly remove the children by
user.organisations.clear()
user.save()
The reason for the behaviour you a facing is, that the String instances are mapped to a table which has no back-refs to the user. That leads to the situation, that the records in that string table are not actually removed and are loaded upon the next database call.

Answer 2

I have read your project code and you have the DataSource bad set. You are using a H2 memory BBDD, but using the MySQL driver instead (in the development environment). It doesnt look good. Set it properly, and try again.
I have test your model, and used:
user.organizations.clear()
without any problems, even using your custom validator.
In other hand you should use a Service instead for all the business logic, not a controller. Because a service is transactional by default.
Here are the changes I did, and works:
// List organizations = []
static hasMany = [organizations: String]
static mapping = {
password column: '`password`'
// organizations lazy: false
}
Removing List organizations. Using the H2 datasource with this config at DataSource development environment:
dbCreate = "create-drop"
url = "jdbc:h2:mem:devDb;MVCC=TRUE;LOCK_TIMEOUT=10000"
username = "sa"
password = ""
And this code works like a charm:
def clearOrganizationFromUser(){
//creating user with timestamp
User user = new User(username: 'username' + new Date(), password: 'password', email: 'email#email.es', accountExpired: false, accountLocked: false,
passwordExpired: false)
List<String> organizations = []
10.times{
organizations << "organization $it"
}
organizations.each{ String organization ->
user.addToOrganizations(organization)
}
user.save()
println "Organizations after saving: ${user.organizations}"
//Its not neccesary but I did it for showing that organization are persisted in DDBB
User newUserFromDDBB = User.get(user.id)
//deleting organization
newUserFromDDBB.organizations.clear()
newUserFromDDBB.save()
println "---> Organizations after deleting: ${newUserFromDDBB.organizations}"
}
Hope It works. If do, please mark as solved.