Hi, expanding on <DAO#auto-fill-created-and-update...

# exposed

[mitch]

Hi, expanding on DAO#auto-fill-created-and-updated-columns-on-entity-change which uses clientDefault, are there any recommendations on what to do if I want updatedAt to be set to the same datetime as insertedAt when we do a new()?

https://github.com/JetBrains/Exposed/issues/342#issuecomment-540487409 gives a nice server-side answer, .defaultExpression(CurrentDateTime()), but what if we want it client side so that the caller has the value set without committing the transaction?

I noticed that the `clientDefault`s are `invoke`d in the order the columns are registered. Is is acceptable to rely on that behavior? If so, I could do something like:

private data class ControlledUtc(var currentTime: LocalDateTime = utcNow()) {
    fun getRefreshed(): LocalDateTime = utcNow().also { currentTime = it }
    fun get(): LocalDateTime = currentTime
}

private val controlledUtc = ControlledUtc()

val insertedAt = datetime("inserted_at").clientDefault { controlledUtc.getRefreshed() }

var updatedAt = datetime("updated_at").clientDefault { controlledUtc.get() }

Thoughts? Other ideas?

[spand]

I think you requirements could be solved by something like this

private class ControlledUtc {
    val currentTime by lazy { utcNow() }
}

private val controlledUtc = ControlledUtc()

val insertedAt = datetime("inserted_at").clientDefault { controlledUtc.get() }

var updatedAt = datetime("updated_at").clientDefault { controlledUtc.get() }

but I cannot see how you would use something like this while still being thread safe and such.

[mitch]

Thanks. The use of lazy is a nice improvement, but I still think we need the getRefreshed to handle multiple calls to new.

Yeah, I'm concerned about thread safety.