bakenezumi / domala

Domain Oriented Database Mapping Framework for Scala


Domala: Doma for Scala

Domala is a database access library for Scala. This wraps Doma2.

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  • Domala uses scalameta to generate code and validate sql mappings at compile time.

  • Select statements are write by yourself. It is automatically mapped to Option[Entity], Seq[Entity], Stream[Entity], Seq[Map[String, Any]], and more.

  • Other statements are automatically generated from Entity. It can also write SQL.

Setup build

when use annotation macro

All functions are available under the setting below.

lazy val metaMacroSettings: Seq[Def.Setting[_]] = Seq(
  addCompilerPlugin("org.scalameta" % "paradise" % "3.0.0-M10" cross CrossVersion.full),
  scalacOptions += "-Xplugin-require:macroparadise",
  scalacOptions in (Compile, console) ~= (_ filterNot (_ contains "paradise")) // macroparadise plugin doesn't work in repl yet.

lazy val yourProject = project.settings(
  // required to validate SQL files at compile time
  compile in Compile := ((compile in Compile) dependsOn (copyResources in Compile)).value,
  libraryDependencies ++= Seq(
    "com.github.domala" %% "domala" % "0.1.0-beta.9",
    "com.github.domala" %% "domala-paradise" % "0.1.0-beta.9" % Provided,
    "org.scalameta" %% "scalameta" % "1.8.0" % Provided,    
    // ... your other library dependencies
  // ... your other project settings

when not use annotation macro

@Dao, @Entity, @Holder can not be used under the setting below.

lazy val yourProject = project.settings(
  libraryDependencies ++= Seq(
    "com.github.domala" %% "domala" % "0.1.0-beta.9"
    // ... your other library dependencies
  // ... your other project settings



A value holder

case class Name(value: String)


Partial class to embed in entity

case class Address(city: String, street: String)


Classes whose instances can be stored in a database

@Entity can be omitted, but some functions are restricted.

case class Person(
  id: Int,
  name: Name,
  age: Option[Int],
  address: Address,
  departmentId: Option[Int],
  version: Option[Int] = None


Trait of data access object

trait PersonDao {

  @Select(sql = """
select *
from person
where id = /*id*/0
  def selectById(id: Int): Option[Person]

  def insert(person: Person): Result[Person]

  def update(person: Person): Result[Person]

SQL can also be described in an external file.

When use external file, the file name must be as follows, and put it on the class path.

META-INF/Dao package name/Dao class name/Dao method name.sql

package example
trait PersonDao {
  def selectByName(name: String): Seq[Person]

External SQL file for this method is as follows.


select *
from person where
/*%if name != null */
  name like /* @prefix(name) */'%' escape '$'


A configuration of a database

object ExampleConfig extends LocalTransactionConfig(
  dataSource = new LocalTransactionDataSource(
    "jdbc:h2:mem:example;DB_CLOSE_DELAY=-1", "sa", null),
  dialect = new H2Dialect,
  naming = Naming.SNAKE_LOWER_CASE
) {


implicit val config = ExampleConfig

// Dao implementation is auto generated.
val dao: PersonDao = PersonDao.impl 

val entity = Person(
  id = 1,
  name = Name("SMITH"),
  age = Some(10),
  address = Address("TOKYO", "YAESU"),
  departmentId = Some(1)

// `Required` is Executes the transaction.
// If processing in block ends normally it commit.
// If Exception occurs it rollback.
Required {
  dao.selectById(1).foreach(e =>
    dao.update(e.copy(age = + 1)))

Run example



Annotation macro doesn't work in repl yet. So, compile separately with sbt ~console or use the following SQL interpolations.

import domala._
// load jdbc driver

// A configuration of database
// domala.jdbc.AdHocConfig works with AutoCommit mode.
implicit val config = jdbc.AdHocConfig("jdbc:h2:mem:example;DB_CLOSE_DELAY=-1")

// `script"..." ` builds a script query statement
script"create table emp(id int serial primary key, name varchar(20))".execute()

// `update"..." ` builds a `INSERT`, `UPDATE`, `DELETE` query statement
Seq("Scott", "Allen").map { name =>
    insert into emp(name) values($name)

// `select"..." ` builds a `SELECT` query statement
select"select * from emp order by id".getMapList
// => List(Map("ID" -> 1, "NAME" -> "Scott"), Map("ID" -> 2, "NAME" -> "Allen"))

select"select id from emp".getList[Int]
// => List(1, 2)

case class ID[E] (value: Int) extends AnyVal
case class Emp(id: ID[Emp], name: String) 
select"select * from emp order by id".getList[Emp]
// => List(Emp(ID(1),Scott), Emp(ID(2),Allen))

// EntityManager is assemble and execute SQL automatically from a entity type
jdbc.EntityManager.insert(Emp(ID(3), "Smith"))

select"select * from emp order by id".getList[Emp]
// => List(Emp(ID(1),Scott), Emp(ID(2),Allen), Emp(ID(3),Smith))

Play integration sample



Apache License, Version 2.0