authorBook.groovy

class Author {
    static hasMany = [books: Book]
    String name
}

class Book {
    static belongsTo = [author: Author]
    String title
}

CoinToss.groovy

package grailsmodelspart1

class CoinToss {

    static constraints = {
    }
}

CoinTossPersistenceTests.groovy

package grailsmodelspart1

import static org.junit.Assert.*
import org.junit.*

class CoinTossPersistenceTests {
	
	CoinTossService coinTossService

	@Test
	void we_can_crud_coin_tosses() {		
		// Make sure the service can list
		def tosses = coinTossService.list()
		def originalTossCount = tosses.size()
		
		// Make sure the service can create
		def ct = new CoinToss()
		coinTossService.save( ct )
		assert coinTossService.list().size() == originalTossCount + 1
		
		// Make sure the serivce can update without creating new instances
		ct.wasHeads = !ct.wasHeads
		coinTossService.save( ct )
		assert coinTossService.list().size() == originalTossCount + 1
		
		// Make sure we can delete
		coinTossService.delete( ct )
		assert coinTossService.list().size() == originalTossCount
	}
}

CoinTossService.groovy

package grailsmodelspart1

class CoinTossService {

	List list() {
		return CoinToss.list()
	}
	
	CoinToss save( coinToss ) {
		coinToss.save()
	}
	
	CoinToss delete( coinToss ) {
		coinToss.delete()
	}

}

CoinTossService2.groovy

package grailsmodelspart1

import groovy.sql.Sql

class CoinTossService {

	def dataSource 
	
	List headsOrTailsReport() {
		return new Sql( dataSource ).rows("""
			select
				count(1) as times_landed_this_side,
				was_heads
			from
				coin_toss
			group by
				was_heads
		""")
	}
	
}

datecreated.groovy

package grailsmodelspart1

class CoinToss {

	Boolean wasHeads = false
	
	// Autotimestamping by convention
	Date dateCreated
	Date lastUpdated
	
	
	static constraints = {
	}
}

dynamicFinder1.groovy

List listHeads() {
	return CoinToss.findByWasHeads( true )
}

dynamicFinder2.groovy

Person.findAllByNameLikeAndNameNot(
  "%Bo%",
  "Bob",
  [
    max : 5,
    offset : 5,
    sort : "name",
    order : "desc"
  ]
)

orm.groovy

Person.findAll( """
		from 
			Person p 
		where
			p.name like '%Bo%'
			and p.name != 'BoB'
		order by
			p.name desc 
	""",
	[
		max : 5,
		offset : 5
	]
)

washeads.groovy

package grailsmodelspart1

class CoinToss {

	Boolean wasHeads = false
	
	static constraints = {
	}
}