Grails databinding multiple domain classes - grails

Question

HI. I have this classes:
class Carro {
String name
String marca
String matricula
static constraints = {
name(nullable:false, blank:false)
}
static mapping = {
version false
}
}
class CarroMovel {
String move
String rodas
String espelhos
Carro carro
static hasMany = [carros: Carro]
static constraints = {
move(nullable:false, blank:false)
}
static mapping = {
version false
}
}
And the controllers:
class CarroController{
def save2 = {
def carroInstance = new Carro()
carroInstance.name = params.name
carroInstance.marca = params.marca
carroInstance.matricula = params.matricula
if (carroInstance.save(flush: true)) {
redirect(uri:"/home.gsp")
}
else {
render(view: "/testeAdd", model: [carroInstance: carroInstance])
}
}
And the view testeAdd.gsp
<g:form controller="carro" action="save2">
<h1>Add New Carro Record</h1>
<p>Basic Information</p>
<label>Name
<span class="small">as</span>
</label>
<input type="text" name="name" value="${carroInstance?.name}" /><br>
<label>Marca
<span class="small">as</span>
</label>
<input type="text" name="marca" value="${carroInstance?.marca}" /><br
<label>Matricula
<span class="small">as</span>
</label>
<input type="text" name="matricula" value="${carroInstance?.matricula}" /><br>
<g:submitButton name="save" value="Save" id="oneone"/>
<div class="spacer"></div>
</g:form>
<g:hasErrors bean="${carroInstance}">
<div class="errors">
<g:renderErrors bean="${carroInstance}" as="list" />
</div>
</g:hasErrors>
This is working good. Now i would like to be able to data binding multiple domain classes. So, along with the current code from my gsp file, i would also like to add carroMovel occurrences all in same save2. Im not sure how to do that, specially cause class Carro will need to have an id from class carroMovel. Any help please? Thank you.
I folowed some suggestions and now the results are as follows (im not concerned about error validation yet):
def save3 = {
def carroInstance = new Carro()
def carroMovelInstance = new CarroMovel()
carroInstance.name = params.carro.name
carroInstance.marca = params.carro.marca
carroInstance.matricula = params.carro.matricula
carroMovelInstance.move = params.carroMovel.move
carroMovelInstance.rodas = params.carroMovel.rodas
carroMovelInstance.espelhos = params.carroMovel.espelhos
carroInstance.save()
carroMovelInstance.carro = carroInstance
carroMovelInstance.save()
}
<g:form controller="carro" action="save3">
<h1>Add New Conference Record</h1>
<p>Basic Information</p>
<label>Name
<span class="small">Add your name</span>
</label>
<input type="text" name="carro.name" value="${carroInstance?.name}" /><br>
<label>Marca
<span class="small">Add your name</span>
</label>
<input type="text" name="carro.marca" value="${carroInstance?.marca}" /><br
<label>Matricula
<span class="small">Add your name</span>
</label>
<input type="text" name="carro.matricula" value="${carroInstance?.matricula}" /><br>
<label>Move
<span class="small">Add your name</span>
</label>
<input type="text" name="carroMovel.move" value="${carroMovelInstance?.move}" /><br>
<label>Rodas
<span class="small">Add your name</span>
</label>
<input type="text" name="carroMovel.rodas" value="${carroMovelInstance?.rodas}" /><br>
<label>Espelho
<span class="small">Add your name</span>
</label>
<input type="text" name="carroMovel.espelho" value="${carroMovelInstance?.espelho}" /><br>
<g:submitButton name="save" value="Save" id="addConference"/>
The Carro object is saved in the database, altought, nothing happens with CarroMovel and it is not saved and i can't figure it out.

Answer 1

First I would change the input names to carro.name, carro.marca, carroMovel.move, ... so that they are differentiated by name.
<input type="text" name="carro.name"/><br>
<input type="text" name="carro.marca"/><br>
<input type="text" name="carroMovel.move"/><br>
This has the advantage that the binding in the controller can be done the standard Grails way, and that the correct values are entered in the form without the value attribute set.
carro.properties = params.carro
carroMovel.properties = params.carroMovel
In the controller action you can also save and link the Carro and CarroMovel instances.
carro.save()
carroMovel.carro = carro
carroMovel.save()
if(carroMovel.hasErrors(){
render(view: 'save3', model: [carro: carro, carroMovel.carroMovel])
}

Answer 2

If I understand your question correctly, you can give this a try.
First, edit our form to include the necessary fields for the CarroMovel class,
e.g
<label>Move
<span class="small">as</span>
</label>
<input type="text" name="move" value="${carroMovelInstance?.move}" />
then
in your save2 action,
def carroInstance = new Carro()
carroInstance.name = params.name
carroInstance.marca = params.marca
carroInstance.matricula = params.matricula
def carroMovelInstance = new CarroMovel()
carroMovelInstance.name = params.move
carroMovelInstance.marca = params.rodasa
carroMovelInstance.matricula = params.espelhos
carroMovelInstance.carro = carroInstance
Since Carro does not belong to CarroMovel saving a carroMovelInstance will not cascade to the carroInstance, therefore you will need to save each instance individually before saving its owning instance.
carroMovelInstance.carro.save()
if (carroMovelInstance.save(flush: true)) {
redirect(uri:"/home.gsp")
}
else {
render(view: "/testeAdd", model: [carroInstance: carroInstance, carroMovelInstance:carroMovelInstance])
}
Let me know if that works out for you.

Answer 3

Some of the other answers may be simpler, but I've been using this technique:
http://omarello.com/2010/08/grails-one-to-many-dynamic-forms/

Answer 4

In order for Carro to cascade save the CarroMovel reference, CarroMovel needs belongsTo = Carro or you need to manually tell hibernate to cascade it upon save using something like this:
class CarroMovel{
static mapping = {
carro cascade: 'all'
}
}
Here's the hibernate documentation about cascading:
https://docs.jboss.org/hibernate/orm/4.0/javadocs/org/hibernate/metamodel/binding/CascadeType.html

Answer 5

I usually use a command object for this type of thing.
In your controller do something like this:
class CarroController {
def show = {
[cmd: new MyCommand()]
}
def save2 = { MyCommand cmd ->
def carro = cmd.carro
if (carro.save()) {
cmd.movel.carro = carro
if (cmd.movel.save()) {
redirect uri: 'home.gsp'
} else {
// show form again
render view: 'show', model:[cmd:cmd]
}
} else {
// show form again
render view: 'show', model:[cmd:cmd]
}
}
// same file or some other class file
class MyCommand {
Carro carro
CarroMovel movel
}
}
You will need to adjust your form a bit as well...
Where you have "Carro" fields reference them like this:
<input type="text" name="carro.matricula" value="${cmd.carro?.matricula}" />
Where you have the "CarroMovel" fields, like this:
<input type="text" name="movel.rodas" value="${cmd.movel?.rodas}" />
This code might not be exactly right (I didn't test it), but should get you down the correct path. Also instead of referencing the objects in the command object, you could just have the fields that you are binding, and then build the actual domain objects from them, either through a helper method (def buildCarro(){...}) or by hand in the controller method.