Appendix B. GORM query reference

 

As you saw in the main chapters, Grails gives you plenty of options when it comes to querying. Of those, in this appendix, we focus on Where and Criteria queries, which are closely related. We detail the syntax for both options and also show you how the criteria map between the two. This will allow you to convert between Where and Criteria queries. For example, you may find the query you need in an online blog post in Criteria query form, whereas you may want to use Where queries exclusively in your code.

B.1. Where queries

You can invoke Where queries in several different ways:

def result = <domainClass>.where { <criteria> }.list()
def result = <domainClass>.where { <criteria> }.get()
def result = <domainClass>.where { <criteria> }.find()
def result = <domainClass>.where { <criteria> }.findBy*()
def result = <domainClass>.where { <criteria> }.findAllBy*()
def result = <domainClass>.find { <criteria> }
def result = <domainClass>.findAll { <criteria> }

There is such a thing as too much choice! The where() method creates a query object but doesn’t execute it. You then use list() if the query can return more than one result, or get() (find() is a synonym) if the query only returns a single domain object or null. The dynamic finders allow you to execute the query and add further criteria in one step.

B.2. Criteria queries