discriminator

Purpose

Customizes the discriminator value used in table-per-subclass inheritance mapping.

Examples

class Content {
	…
}
class PodCast extends Content{
	…
	static mapping = {
		discriminator "audio"
	}
}

Description

Usage: discriminator(string/map)

Arguments:

• column (optional) - The column name to store the discriminator
• value - The value to use for the discriminator

By default when mapping inheritance Grails uses a single-table model so that all subclasses share the same table. A discriminator column is then used to help Grails tell what type a particular row is. By default the class name is stored as the value of this column. You can use the discriminator method to customize the value stored:

class Content {
	…
}
class PodCast extends Content{
	…
	static mapping = {
		discriminator "audio"
	}
}

You can also customize the discriminator column name:

class Content {
	…
}
class PodCast extends Content{
	…
	static mapping = {
		discriminator column:"content_type",  value: "audio"
	}
}