Grails on Groovy > Way in Grails to Eager Fetch the Whole Record | Load Related Entity With Single Query

I am trying to find if there is any way in Grails to eager fetch complete records instead of a left Join.

For example, let you have domain named Tabel1 with following structure and another domain named Table3 below:

package com.pkm class Table1 { Long id String name String roll static mapping = { table("table1") } static belongsTo = [ table3: Table3 ] static constraints = { table3 nullable: true } } package com.pkm class Table3 { Long id String name }

So when you get/list Table1, what will be the default behavior? It will load only Table1 data, not other associated data like Table3.

There is a procedure to load selected associated by joining them. See the below example, enabled eager face data when creating criteria:

package com.pkm import grails.transaction.Transactional import org.hibernate.FetchMode import org.hibernate.sql.JoinType import org.springframework.transaction.TransactionStatus @Transactional class HomeService { TransactionStatus transactionStatus void callMe() { List list = Table1.createCriteria().list { createCriteria("table3", "j3", JoinType.LEFT_OUTER_JOIN) setFetchMode("j3", FetchMode.JOIN) order("id", "desc") setMaxResults(20) } list.each { Table1 table1 -> println("Name=${table1.name}, Table3=${table1.table3?.name}") } } }

Now we will print the query generated:

select this_.id as id1_0_1_, this_.name as name2_0_1_, this_.roll as roll3_0_1_, this_.table3_id as table4_0_1_, j3x1_.id as id1_2_0_, j3x1_.name as name2_2_0_ from table1 this_ left outer join table3 j3x1_ on this_.table3_id=j3x1_.id order by this_.id desc limit ?

You observed that in select query, both Table1 and Table3 exists. And this is how we can implement eager face data when creating criteria builder to get data.