(Quick Reference)
namedQueries
目的
Purpose
The
namedQueries static property defines named queries. Named queries support the criteria builder syntax. See the section on the
Criteria Builder in the user guide for more information.
使用例
Examples
class Publication { String title
String author
Date datePublished
Integer numberOfPages static namedQueries = {
recentPublications {
def now = new Date()
gt 'datePublished', now - 365
} oldPublicationsLargerThan { pageCount ->
def now = new Date()
lt 'datePublished', now - 365
gt 'numberOfPages', pageCount
} publicationsWithBookInTitle {
like 'title', '%Book%'
} recentPublicationsWithBookInTitle {
// calls to other named queries…
recentPublications()
publicationsWithBookInTitle()
}
}
}// get all recent publications…
def recentPubs = Publication.recentPublications.list()// get up to 10 recent publications, skip the first 5…
def recentPubs = Publication.recentPublications.list(max: 10, offset: 5)// get a single recent publication
def recentPub = Publication.recentPublications.get()// get the number of recent publications…
def numberOfRecentPubs = Publication.recentPublications.count()// get a recent publication with a specific id…
def pub = Publication.recentPublications.get(42)// get all recent publications where title = 'Some Title'
def pubs = Publication.recentPublications.findAllWhere(title: 'Some Title')// get a recent publication where title = 'Some Title'
def pub = Publication.recentPublications.findWhere(title: 'Some Title')// dynamic finders are supported
def pubs = Publication.recentPublications.findAllByTitle('Some Title')// get all old publications with more than 350 pages
def pubs = Publication.oldPublicationsLargerThan(350).list()// get all old publications with more than 350 pages
// and the word 'Grails' in the title
def pubs = Publication.oldPublicationsLargerThan(350).findAllByTitleLike('%Grails%')// get all recent publications with 'Book' in their title
def pubs = Publication.recentPublicationsWithBookInTitle().list()The
list method on named queries supports the same attributes as the static
list method added to domain classes (sort, order, ignoreCase, fetch etc...). See the
list docs for details.
Note that calling something like Publication.recentPublications.get(42) is not the same as calling something like Publication.get(42). The former will only return a Publication if the Publication with id 42 meets all the criteria defined in the recentPublications named query.
Named criteria support
listDistinct():
class PlantCategory { Set plants
String name static hasMany = [plants: Plant] static namedQueries = {
withPlantsInPatch {
plants {
eq 'goesInPatch', true
}
}
}
}class Plant {
boolean goesInPatch
String name
}PlantCategory.withPlantsInPatch.listDistinct()
Named criteria support additional criteria being supplied at invocation time in the form of a criteria closure:
// get all recent publications with author names beginning with Tony or Phil…
def books = Publication.recentPublications {
or {
like 'author', 'Tony%'
like 'author', 'Phil%'
}
}// get the number of recent publications with
// author names beginning with Tony or Phil…
def numberOfBooks = Publication.recentPublications.count {
or {
like 'author', 'Tony%'
like 'author', 'Phil%'
}
}Named criteria may be chained together. When criteria are chained together, the query will be generated as if all of the chained criteria had been combined in a single criteria closure.
// recent publications with 'Book' in the title
def books = Publication.recentPublications.publicationsWithBookInTitle.list()// old publications with more than 500 pages and with 'Book' in the title
def books = Publication.oldPublicationsLargerThan(500)
.publicationsWithBookInTitle
.list()When a named query involves a domain class relationship and the relationship class defines a named query, that named query may be accessed directly as a method call. An example:
class Author { static hasMany = [publications: Publication] static namedQueries = {
authorsWithRecentPublications {
publications {
// invoking a named query defined in the Publication class…
recentPublications()
}
}
}
}class Publication { Author author static namedQueries = {
recentPublications {
def now = new Date()
gt 'datePublished', now - 10
}
}
}
