Hi everyone, I just started with Exposed (for addi...

# exposed

[Paul at Avans Breda]

Hi everyone, I just started with Exposed (for adding persistence in a Ktor api).
In one of my entity types I have a property storing a list of image filenames. I see that recent Exposed versions support ArrayColumnType, but I fail to use it properly.
Is there an Exposed DAO example how to use ArrayColumnType?

[Oleg Babichev]

Hi, I'd to confirm which database type do you expect to use?

ArrayColumnType is made to use array database type that is supported by Postgres and H2 only (better to recheck).

Here is just a simple example of how to use it:

object TestTable : IntIdTable() {
        val files = array<String>("files")
    }

    class TestEntity(id: EntityID<Int>) : IntEntity(id) {
        companion object : IntEntityClass<TestEntity>(TestTable)

        var files by TestTable.files
    }

    @Test
    fun test() {
        withTables(TestTable) {
            TestEntity.new {
                files = listOf("f1.pdf", "f2.pdf")
            }

            val entry = TestTable.selectAll().first()
            assertEqualLists(listOf("f1.pdf", "f2.pdf"), entry[TestTable.files])
        }
    }

If you want to store them in another column type (like varchar or text) you will have to make client side conversion of the data (manually or with transform API for example)

If you describe your case more detailed, I can try make another example)

[Paul at Avans Breda]

Thanks Oleg! I intend to use H2.
I will try to apply your example in my own types.