The Grails Framework 3.0.10

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(Quick Reference) # embedded ## Purpose Supports embedding domain components into domain classes - otherwise known as composition. ## Examples Given these domain classes:

    class Person {    String name
        Country bornInCountry
        Country livesInCountry    static embedded = ['bornInCountry', 'livesInCountry']
    }// If you don't want an associated table created for this class, either
    // define it in the same file as Person or put Country.groovy under the
    // src/groovy directory.
    class Country {
        String iso3
        String name
    }
Grails will generate a `person` database table that looks like:
Column | Type
--- | ---
NAME | VARCHAR(255)
BORN_IN_COUNTRY_ISO3 | VARCHAR(255)
BORN_IN_COUNTRY_NAME | VARCHAR(255)
LIVES_IN_COUNTRY_ISO3 | VARCHAR(255)
LIVES_IN_COUNTRY_NAME | VARCHAR(255)
## Description An embedded component does not store its data in its own table as a regular domain class relationship does. Instead, the data is included in the owner's table. So in the above example, the `Country` fields appear in the `person` table. This means that queries are faster because there is no join required, but you may end up with duplicate data across tables. The embedded component class is typically declared in the same source file as the owning class or in its own file under `src/groovy`. You can put the component class under `grails-app/domain`, but if you do so Grails will automatically create a dedicated table for it. Putting the class under `src/groovy` is usually the best option because you can then share the component across multiple domain classes. Querying on embedded properties is no different from querying on regular relationships, so you can for example still do:
    Person.findAllByBornInCountry(brazil)
    Person.findAllByLivesInCountry(france)
where `brazil` and `france` are instances of `Country`. | Quick Reference (hide)