(Quick Reference) ## discriminator ### Purpose Customizes the discriminator column used in table-per-hierarchy inheritance mapping. Has no effect when using 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 `formula` (optional) - an SQL expression that is executed to evaluate the type of class. Use this or `column` but not both `type` (optional defaults to string) - the Hibernate type, used for the where clause condition to know if it needs to wrap it with ' By default when mapping inheritance Grails uses a single-table model where all classes share the same table. A discriminator column is used to determine the type for each row, by default the full class name. You can use the `discriminator` method to customize what’s stored:
    class Content {
        ...
    }
    class PodCast extends Content {
        ...
        static mapping = {
            discriminator "audio"
        }
    }
You can also customize the discriminator column name:
    class Content {
        ...
        static mapping = {
            discriminator column: "content_type"
        }
    }
    class PodCast extends Content {
        ...
        static mapping = {
            discriminator value: "audio"
        }
    }
Or you can use a formula:
    class Content {
        ...
        static mapping = {
            discriminator value: "1", type: "integer",
                formula: "case when CLASS_TYPE in ('a', 'b', 'c') then 0 else 1 end",
        }
    }
    class PodCast extends Content {
        ...
        static mapping = {
            discriminator value: "0"
        }
    }
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