Grails 2.1 Join Query - grails

Question

I m new user in Grails. I don't know how to write projection query. Here is my code. please anyone help me for grails projection query.
From Join table I want to find username which is consist in user table
Given the following example domains:
class User{
transient springSecurityService
String username
String password
boolean enabled
boolean accountExpired
boolean accountLocked
boolean passwordExpired
static mapping = {
table 't04t001'
id column: 'f_account_id'
username column: 'f_username', length: 10
password column: 'f_password', length: 100
enabled column: 'f_account_active'
accountExpired column: 'f_account_expired'
accountLocked column: 'f_account_locked'
passwordExpired column: 'f_password_expired'
version column: 'f_revision'
}
}
class Role{
String role
static mapping = {
table 't04t003'
id column : 'f_role_id'
role column : 'f_role'
version column : 'f_revision'
cache true
}
}
class UserRole implements Serializable {
User user
Role role
static mapping = {
table 't04j002'
id composite : ['role', 'user']
role column :'k_role_id'
user column :'k_user_id'
version false
}
}
I can't figure out how to build the criteria to find all the user. I tried the following:
def criteria = UserRole.createCriteria()
def list = criteria.list {
projections {
user{
ilike('username', 'omar')
}
}
}
In console mode i have seen this query with message
Hibernate:
select
this_.k_role_id as k1_3406_0_,
this_.k_user_id as k2_3406_0_
from
t04j002 this_
where
(
lower(user_alias1_.f_username) like ?
)
However, it says Unknown column 'user_alias1_.f_username' in 'where clause'.
But i cant figure out this(user_alias1_) alias

Answer 1

I am not exactly clear on what you want to retrieve from which table. So based on your criteria query, here is how to retrieve user from the UserRole table.
def criteria = UserRole.createCriteria()
def result = criteria.list {
projections {
property("user")
}
user {
eq("username", "omar") //strict match
}
}
return result;
What this does is it builds a list that has the user.username as omar. By default the result will be the UserRole object, but to get user object instead we used projections.
Update:
Your Domain class seems a bit out of grails conventions. Why not user something like this?
//User.groovy
class User {
String username
// ..
static constraints = {
username blank: false, nullable: false, maxSize: 10
}
}
//UserRole.groovy
// Since you are using composite keys, we have to implement serializable. But is there a need for composite key in your situtation?
class UserRole implements Serializable {
User user
// ..
}
In you service class
// UserRoleService.groovy
def getUser(String username) {
def criteria = UserRole.createCriteria()
def result = criteria.get {
projections {
property("user")
}
user {
ilike("username", username)
}
}
return result;
}
And to call the service method from controller,
// ExampleController.groovy
class ExampleController {
def userRoleService
def index() {}
def someThing(String username) {
def user = userRoleService.getUser(username)
println user?.username
// ..
}
}