Grails 3.1 - Multiple inserts into domain

Question

When adding a single Book, you can just do:

String author = 'John Smith'
String title = 'First Book'
def book = new Book(author: author, title: title)
book.save(flush: flush, insert: true)

Say I want to add a number of books at once, for instance if the input is:

String author = 'John Smith'
String title = ['First Book', 'Second Book', 'Third Book']

How can I save all the books with one call to the database?

Answer 1

A Groovy SQL Solution:

def author = 'John Smith'
def titles = ['First Book', 'Second Book', 'Third Book']

def bookClassMetadata = sessionFactory.getClassMetadata(Book)

def bookTableName = bookClassMetadata.tableName

def authorColumnName = bookClassMetadata.propertyMapping.getColumnNames('author')[0]
def titleColumnName  = bookClassMetadata.propertyMapping.getColumnNames('title')[0]

def batchSize = 500

def batchSQL = "INSERT INTO ${bookTableName} (${authorColumnName}, ${titleColumnName})" +
               " VALUES (?,?)"

def sql = new Sql(dataSource)

sql.withBatch(batchSize, batchSQL) { preparedStatement ->

    titles.each { title ->

                preparedStatement.addBatch([author, title])
    }
}