How to create 3 domain relationships in Grails 3? - grails

Question

I have 3 domain class and I need to define their relationships but I find no luck in defining them correctly. Can somebody rectify my code? I have always get the error unknown column pointing to an id. Please help. Below are my codes. Thank you.
Todo.groovy class
package todoScaff
import userScaff.User
import categoryScaff.Category
class Todo {
String name
String note
Date createDate
Date dueDate
Date completedDate
String priority
String status
User owner
Category category
static belongsTo = [User, Category]
static constraints = {
name(blank:false)
createDate()
priority()
status()
note(maxsize:1000, nullable:true)
completedDate(nullable:true)
dueDate(nullable:true)
}
String toString() {
name
}
}
Category.groovy class
package categoryScaff
import todoScaff.Todo
import userScaff.User
class Category {
String name
String description
User user
static belongsTo = User
static hasMany = [todos: Todo]
static constraints = {
name(blank:false)
}
String toString(){
name
}
}
User.groovy class
package userScaff
import todoScaff.Todo
import categoryScaff.Category
class User {
String userName
String fname
String lname
static hasMany = [todos: Todo, categories: Category]
static constraints = {
userName(blank:false, unique:true)
fname(blank:false)
lname(blank:false)
}
String toString(){
"$lname, $fname"
}
}
Errors

Answer 1

I'm fairly certain your SQL tables are incorrect.
I created a small project with your 3 domain classes and used the grails command schema-export; after removing everything that doesn't relate to the domain relationship, the structure should look like this:
create table category (
id bigint,
user_id bigint,
);
create table todo (
id bigint,
category_id bigint,
owner_id bigint,
);
create table user (
id bigint
);
If your table structure doesn't resemble this, you should either change it to match or use the static mapping = {} closure in the domain class to indicate the proper column names.
Static Mapping
In Todo:
static mapping = {
owner column: 'owner_id' // change owner_id to match your owner column within todo
category column: 'category_id' // change category_id to match your category column within todo
}
In Category:
static mapping = {
owner user: 'user_id' // change user_id to match your user column within category
}