Play2's anorm can't work on postgresql - postgresql

Question

I found that the row parsers of play2's anorm depend on the meta data returned by jdbc driver.
So in the built-in sample "zentasks" provided by play, I can find such code:
object Project {
val simple = {
get[Pk[Long]]("project.id") ~
get[String]("project.folder") ~
get[String]("project.name") map {
case id~folder~name => Project(id, folder, name)
}
}
}
Please notice that the fields all have a project. prefix.
It works well on h2 database, but not on postgresql. If I use portgresql, I should write it as:
object Project {
val simple = {
get[Pk[Long]]("id") ~
get[String]("folder") ~
get[String]("name") map {
case id~folder~name => Project(id, folder, name)
}
}
}
I've asked this in play's google group, and Guillaume Bort said:
Yes if you are using postgres it's probably the cause. The postgresql
jdbc driver is broken and doesn't return table names.
If the postgresql's jdbc driver really have this issue, I think there will be a problem for anorm:
If two tables have fields with the same name, and I query them with join, anorm won't get the correct values, since it can't find out which name belongs to which table.
So I write a test.
1. create tables on postgresql
create table a (
id text not null primary key,
name text not null
);
create table b (
id text not null primary key,
name text not null,
a_id text,
foreign key(a_id) references a(id) on delete cascade
);
2. create anorm models
case class A(id: Pk[String] = NotAssigned, name: String)
case class B(id: Pk[String] = NotAssigned, name: String, aId: String)
object A {
val simple = {
get[Pk[String]]("id") ~
get[String]("name") map {
case id ~ name =>
A(id, name)
}
}
def create(a: A): A = {
DB.withConnection { implicit connection =>
val id = newId()
SQL("""
insert into a (id, name)
values (
{id}, {name}
)
""").on('id -> id, 'name -> a.name).executeUpdate()
a.copy(id = Id(id))
}
}
def findAll(): Seq[(A, B)] = {
DB.withConnection { implicit conn =>
SQL("""
select a.*, b.* from a as a left join b as b on a.id=b.a_id
""").as(A.simple ~ B.simple map {
case a ~ b => a -> b
} *)
}
}
}
object B {
val simple = {
get[Pk[String]]("id") ~
get[String]("name") ~
get[String]("a_id") map {
case id ~ name ~ aId =>
B(id, name, aId)
}
}
def create(b: B): B = {
DB.withConnection { implicit conneciton =>
val id = UUID.randomUUID().toString
SQL("""
insert into b (id, name, a_id)
values (
{id}, {name}, {aId}
)
""").on('id -> id, 'name -> b.name, 'aId -> b.aId).executeUpdate()
b.copy(id = Id(id))
}
}
}
3. test cases with scalatest
class ABTest extends DbSuite {
"AB" should "get one-to-many" in {
running(fakeApp) {
val a = A.create(A(name = "AAA"))
val b1 = B.create(B(name = "BBB1", aId = a.id.get))
val b2 = B.create(B(name = "BBB2", aId = a.id.get))
val ab = A.findAll()
ab foreach {
case (a, b) => {
println("a: " + a)
println("b: " + b)
}
}
}
}
}
4. the output
a: A(dbc52793-0f6f-4910-a954-940e508aab26,BBB1)
b: B(dbc52793-0f6f-4910-a954-940e508aab26,BBB1,4a66ebe7-536e-4bd5-b1bd-08f022650f1f)
a: A(d1bc8520-b4d1-40f1-af92-52b3bfe50e9f,BBB2)
b: B(d1bc8520-b4d1-40f1-af92-52b3bfe50e9f,BBB2,4a66ebe7-536e-4bd5-b1bd-08f022650f1f)
You can see that the "a"s have name of "BBB1/BBB2", but not "AAA".
I tried to redefine the parsers with prefixes as:
val simple = {
get[Pk[String]]("a.id") ~
get[String]("a.name") map {
case id ~ name =>
A(id, name)
}
}
But it will report errors that they can't find specified fields.
Is it a big issue of anorm? Or do I miss something?

Answer 1

The latest play2(RC3) has solved this problem by checking the class name of meta object:
// HACK FOR POSTGRES
if (meta.getClass.getName.startsWith("org.postgresql.")) {
meta.asInstanceOf[{ def getBaseTableName(i: Int): String }].getBaseTableName(i)
} else {
meta.getTableName(i)
}
But be careful if you want to use it with p6spy, it doesn't work because the class name of meta will be "com.p6spy....", not "org.postgresql....".