(Quick Reference)
id
Purpose
Customizes the way the identifier for a domain class is generated
Examples
class Book {
static mapping = {
id generator: 'hilo',
params: [table: 'hi_value', column: 'next_value', max_lo: 100]
}
}Description
Usage:
id(map)Arguments:
generator (optional) - The name of the generator to use. Can be increment, identity, sequence, hilo, seqhilo, uuid, guid, native, assigned, select, foreign or sequence-identity. See Hibernate reference documentation for more information.composite (optional) - Takes a list of property names to use that form the composite identifiername (optional) - The property name to use as the identifierparams (optional) - Any parameters to pass to the defined identity generatorcolumn (optional) - The column name to map the identifier to. The remaining column definition properties are also available.
By default GORM uses the native strategy to generate a database identifier for each entity (typically an auto-incrementing column or a sequence). You can alter this with the
id methods
generator argument:
static mapping = {
id generator: 'hilo',
params: [table: 'hi_value', column: 'next_value', max_lo: 100]
}You can also use the method to define a composite identifier:
static mapping = {
id composite: ['title', 'author']
}or change the name of the property that defines the identifier:
static mapping = {
id name: 'title'
}You can also alter the column definition:
static mapping = {
id column: 'book_id', type: 'integer'
}See the section on
Custom Database Identity in the user guide for more information.
