Slick driver for Ingres

[Ivan Grebenik]

Hello there! 

I'm trying to write a slick driver for Ingres 10.x and 57 tests pass successfully out of 88 but still I've run in few problems I want you to give advices for me.

The problem is how Ingres extracts current value form a sequence. First of all, it has CURRVAL and NEXTVAL to work around sequence values. Then CURRVAL is not populated until after NEXTVAL has been used...

Here is an example.

* create sequence "s1" increment by 1 start with 11 maxvalue 1000 nocache nocycle;\g

* select "s1".CURRVAL;\g

I get the "E_QE00A2 An attempt to issue a CURRENT VALUE request on a sequence was made before issuing a NEXT VALUE request."

So if I issue the NEXTVAL beforehand when it works fine:

* select "s1".NEXTVAL;\g

I get 11,

and then do CURRENT VALUE:

* select "s1".CURRVAL;

and now I get the 11.

Due to this specific behavior the tests under com.typesafe.slick.testkit.tests.SequenceTest.test1 failed. 

To be more precise,

ifCap(scap.sequenceCurr) {

    val curr = mySequence.curr.run // this code fails

    assertEquals(220, curr)

}

It is not big deal to disable this feature at the testing side but how can I workaround it in the driver itself?

Just to override expr method doesn't look like it solve the issue here.

class QueryBuilder(tree: Node, state: CompilerState) extends super.QueryBuilder(tree, state) {

    protected override val supportsTuples = false

    protected override val concatOperator = Some("||")

    protected override val hasPiFunction = true // since version 9.2

    override def expr(n: Node, skipParens: Boolean = false) = n match {

      case Library.NextValue(SequenceNode(name))    => b"${quoteIdentifier(name)}.NEXTVAL"

      case Library.CurrentValue(SequenceNode(name)) => b"${quoteIdentifier(name)}.CURRVAL" 

      case _ => super.expr(n, skipParens)

    }

  }

How could I override the select quiery behavior to comply to Ingres one?

Thanks in advance.

[Ivan Grebenik]

BTW, I use slick 2.1.0