support optional uuid columns

build.sbt

@@ -38,7 +38,7 @@ val testcontainersVersion = "0.40.12"
 
 lazy val root = project
   .in(file("."))
-  .aggregate(magnum, magnumPg)
+  .aggregate(magnum, magnumPg, magnumMySql)
 
 lazy val magnum = project
   .in(file("magnum"))
@@ -74,3 +74,17 @@ lazy val magnumPg = project
       "com.dimafeng" %% "testcontainers-scala-postgresql" % testcontainersVersion % Test
     )
   )
+
+lazy val magnumMySql = project
+  .in(file("magnum-mysql"))
+  .dependsOn(magnum)
+  .settings(
+    Test / fork := true,
+    publish / skip := false,
+    libraryDependencies ++= Seq(
+      "mysql" % "mysql-connector-java" % "8.0.32" % Test,
+      "org.scalameta" %% "munit" % "0.7.29" % Test,
+      "com.dimafeng" %% "testcontainers-scala-munit" % testcontainersVersion % Test,
+      "com.dimafeng" %% "testcontainers-scala-mysql" % testcontainersVersion % Test
+    )
+  )

magnum-mysql/src/main/scala/com/augustnagro/magnum/mysql/MySqlCodec.scala

@@ -0,0 +1,20 @@
+package com.augustnagro.magnum.mysql
+
+import com.augustnagro.magnum.DbCodec
+
+import java.sql.{PreparedStatement, ResultSet, Types}
+import java.util.UUID
+
+object MySqlCodec:
+
+  given VarCharUUIDCodec: DbCodec[UUID] with
+    def queryRepr: String = "?"
+    val cols: IArray[Int] = IArray(Types.VARCHAR)
+    def readSingle(rs: ResultSet, pos: Int): UUID = {
+      val uuidString = rs.getString(pos)
+      uuidString match
+        case null => null
+        case x    => UUID.fromString(x)
+    }
+    def writeSingle(entity: UUID, ps: PreparedStatement, pos: Int): Unit =
+      ps.setString(pos, entity.toString)

magnum-mysql/src/test/resources/mysql-user.sql

@@ -0,0 +1,11 @@
+drop table if exists mag_user;
+
+create table mag_user (
+    id bigint auto_increment primary key,
+    social_id varchar(36)
+);
+
+insert into mag_user (social_id) values
+('d06443a6-3efb-46c4-a66a-a80a8a9a5388'),
+('529b6c6d-7228-4da5-81d7-13b706f78ddb'),
+(null);

magnum-mysql/src/test/scala/MySqlCodecTests.scala

@@ -0,0 +1,80 @@
+import com.dimafeng.testcontainers.MySQLContainer
+import com.dimafeng.testcontainers.munit.fixtures.TestContainersFixtures
+import com.mysql.cj.jdbc.MysqlDataSource
+import munit.FunSuite
+import org.testcontainers.utility.DockerImageName
+
+import java.nio.file.{Files, Path}
+import javax.sql.DataSource
+import scala.util.Using.Manager
+import com.augustnagro.magnum.mysql.MySqlCodec.VarCharUUIDCodec
+import com.augustnagro.magnum.*
+
+import java.util.UUID
+
+class MySqlCodecTests extends FunSuite, TestContainersFixtures {
+
+  case class MagUserCreator(
+      socialId: Option[UUID]
+  ) derives DbCodec
+
+  @Table(MySqlDbType, SqlNameMapper.CamelToSnakeCase)
+  case class MagUser(
+      @Id id: Long,
+      socialId: Option[UUID]
+  ) derives DbCodec
+
+  val userRepo = Repo[MagUserCreator, MagUser, Long]
+
+  test("select nullable uuid"):
+    connect(ds()):
+      val users = userRepo.findAll
+      assert(users.exists(_.socialId.isEmpty))
+      assert(
+        users.exists(
+          _.socialId.contains(
+            UUID.fromString("529b6c6d-7228-4da5-81d7-13b706f78ddb")
+          )
+        )
+      )
+
+  test("insert uuid"):
+    connect(ds()):
+      val uuid = UUID.randomUUID()
+      val uc = MagUserCreator(socialId = Some(uuid))
+      userRepo.insert(uc)
+      val users = userRepo.findAll
+      assert(users.exists(_.socialId.contains(uuid)))
+
+  test("insert null uuid"):
+    connect(ds()):
+      val existingNullCount = userRepo.findAll.count(_.socialId.isEmpty)
+      val uc = MagUserCreator(socialId = None)
+      userRepo.insert(uc)
+      val newNullCount = userRepo.findAll.count(_.socialId.isEmpty)
+      assertEquals(newNullCount, existingNullCount + 1)
+
+  val mySqlContainer = ForAllContainerFixture(
+    MySQLContainer
+      .Def(dockerImageName = DockerImageName.parse("mysql:8.0.32"))
+      .createContainer()
+  )
+
+  override def munitFixtures: Seq[Fixture[_]] =
+    super.munitFixtures :+ mySqlContainer
+
+  def ds(): DataSource =
+    val mySql = mySqlContainer()
+    val ds = MysqlDataSource()
+    ds.setURL(mySql.jdbcUrl)
+    ds.setUser(mySql.username)
+    ds.setPassword(mySql.password)
+    ds.setAllowMultiQueries(true)
+    val userSql =
+      Files.readString(Path.of(getClass.getResource("/mysql-user.sql").toURI))
+    Manager(use =>
+      val con = use(ds.getConnection)
+      use(con.prepareStatement(userSql)).execute()
+    ).get
+    ds
+}

magnum/src/main/scala/com/augustnagro/magnum/DbCodec.scala

@@ -291,7 +291,7 @@ object DbCodec:
 
   given UUIDCodec: DbCodec[UUID] with
     def queryRepr: String = "?"
-    val cols: IArray[Int] = IArray(Types.JAVA_OBJECT)
+    val cols: IArray[Int] = IArray(Types.OTHER)
     def readSingle(rs: ResultSet, pos: Int): UUID =
       rs.getObject(pos, classOf[UUID])
     def writeSingle(entity: UUID, ps: PreparedStatement, pos: Int): Unit =

magnum/src/test/resources/clickhouse-person.sql

@@ -5,7 +5,8 @@ create table person (
     first_name Nullable(String),
     last_name String not null,
     is_admin Bool not null,
-    created DateTime not null default now()
+    created DateTime not null default now(),
+    social_id Nullable(UUID)
 )
 engine = MergeTree()
 order by created;
@@ -16,54 +17,62 @@ insert into person values
     'George',
     'Washington',
     true,
-    toDateTime('2023-03-05 02:26:00')
+    toDateTime('2023-03-05 02:26:00'),
+    toUUID('d06443a6-3efb-46c4-a66a-a80a8a9a5388')
 ),
 (
     toUUID('12970806-606d-42ff-bb9c-3187bbd360dd'),
     'Alexander',
     'Hamilton',
     true,
-    toDateTime('2023-03-05 02:27:00')
+    toDateTime('2023-03-05 02:27:00'),
+    toUUID('529b6c6d-7228-4da5-81d7-13b706f78ddb')
 ),
 (
     toUUID('834a2bd2-6842-424f-97e0-fe5ed02c3653'),
     'John',
     'Adams',
     true,
-    toDateTime('2023-03-05 02:28:00')
+    toDateTime('2023-03-05 02:28:00'),
+    null
 ),
 (
     toUUID('60492bb2-fe02-4d02-9c6d-ae03fa6f2243'),
     'Benjamin',
     'Franklin',
     true,
-    toDateTime('2023-03-05 02:29:00')
+    toDateTime('2023-03-05 02:29:00'),
+    null
 ),
 (
     toUUID('2244eef4-b581-4305-824f-efe8f70e6bb7'),
     'John',
     'Jay',
     true,
-    toDateTime('2023-03-05 02:30:00')
+    toDateTime('2023-03-05 02:30:00'),
+    null
 ),
 (
     toUUID('fb3c479a-0521-4f06-b6ad-218db867518c'),
     'Thomas',
     'Jefferson',
     true,
-    toDateTime('2023-03-05 02:31:00')
+    toDateTime('2023-03-05 02:31:00'),
+    null
 ),
 (
     toUUID('8fefe1d8-20eb-44a0-84da-d328334e1e11'),
     'James',
     'Madison',
     true,
-    toDateTime('2023-03-05 02:32:00')
+    toDateTime('2023-03-05 02:32:00'),
+    null
 ),
 (
     toUUID('8a2d842a-0d03-463c-8c34-43b38120f9e4'),
     null,
     'Nagro',
     false,
-    toDateTime('2023-03-05 02:33:00')
+    toDateTime('2023-03-05 02:33:00'),
+    null
 );

magnum/src/test/resources/h2-person.sql

@@ -5,15 +5,16 @@ create table person (
     first_name varchar(50),
     last_name varchar(50) not null,
     is_admin boolean not null,
-    created timestamp default current_timestamp
+    created timestamp default current_timestamp,
+    social_id UUID
 );
 
-insert into person (first_name, last_name, is_admin, created) values
-('George', 'Washington', true, now()),
-('Alexander', 'Hamilton', true, now()),
-('John', 'Adams', true, now()),
-('Benjamin', 'Franklin', true, now()),
-('John', 'Jay', true, now()),
-('Thomas', 'Jefferson', true, now()),
-('James', 'Madison', true, now()),
-(null, 'Nagro', false, now());
+insert into person (first_name, last_name, is_admin, created, social_id) values
+('George', 'Washington', true, now(), 'd06443a6-3efb-46c4-a66a-a80a8a9a5388'),
+('Alexander', 'Hamilton', true, now(), '529b6c6d-7228-4da5-81d7-13b706f78ddb'),
+('John', 'Adams', true, now(), null),
+('Benjamin', 'Franklin', true, now(), null),
+('John', 'Jay', true, now(), null),
+('Thomas', 'Jefferson', true, now(), null),
+('James', 'Madison', true, now(), null),
+(null, 'Nagro', false, now(), null);

magnum/src/test/resources/pg-person.sql

@@ -5,15 +5,16 @@ create table person (
     first_name varchar(50),
     last_name varchar(50) not null,
     is_admin boolean not null,
-    created timestamptz not null default now()
+    created timestamptz not null default now(),
+    social_id UUID
 );
 
-insert into person (first_name, last_name, is_admin, created) values
-('George', 'Washington', true, now()),
-('Alexander', 'Hamilton', true, now()),
-('John', 'Adams', true, now()),
-('Benjamin', 'Franklin', true, now()),
-('John', 'Jay', true, now()),
-('Thomas', 'Jefferson', true, now()),
-('James', 'Madison', true, now()),
-(null, 'Nagro', false, timestamp '1997-08-12');
+insert into person (first_name, last_name, is_admin, created, social_id) values
+('George', 'Washington', true, now(), 'd06443a6-3efb-46c4-a66a-a80a8a9a5388'),
+('Alexander', 'Hamilton', true, now(), '529b6c6d-7228-4da5-81d7-13b706f78ddb'),
+('John', 'Adams', true, now(), null),
+('Benjamin', 'Franklin', true, now(), null),
+('John', 'Jay', true, now(), null),
+('Thomas', 'Jefferson', true, now(), null),
+('James', 'Madison', true, now(), null),
+(null, 'Nagro', false, timestamp '1997-08-12', null);