Grails GORM唯一约束

Question

I've got the following ListProducts domain object;

String name
Date lastUpdated
Date dateCreated = new Date()
String lastUpdatedBy
CatLists catLists // 
Product product // has a composite primary key
ListProducts listProducts

static constraints = {
    name nullable: true, blank: true
    catLists nullable: false
    lastUpdatedBy nullable: true
    lastUpdated nullable: true
    dateCreated nullable: false
    product unique: 'listProducts'
}

static mapping = {
    version true
    table 'list_products'
    sort "name"
}

The Product domain class has the following constraint which is a composite key

FOREIGN KEY (product_fulfillment_sku, product_merchant_id) REFERENCES product(fulfillment_sku, merchant_id)

as it doest not have a primary key ie ID as the table is dropped due to a batch job so the unique values are the sku and the merchant id.

I can see in the list_products table the product_fulfillment_sku, product_merchant_id and cat_lists_id columns, but how do I represent this in grails domain classes so that product cant be added if it already exists?

What I want to achieve is that a product can be in many ListProducts groupings but only once per grouping.

Grails v2.2.1 against Postgres Sql database!

Any ideas?

J

Answer 1

So the work around I got was to remove the dependency on the unique constraint. This would also block parrallel lookups as the table is huge. Took some inspiration from Performance Collections

Answer 2

You can use unique constraint in domain class which looks like

domain1 unique:"domain2"

Both domain1 and domain2 must be a object not collection.

if you are using collection you can create another mapping class which can use unique constraint.