lucidsoftware/relate

Blazingly fast JDBC access library for Scala

Gregg Hernandez

@gregghz

I'm not sure yet, I haven't had a chance to test that one

Gregg Hernandez

@gregghz

@Fristi The column type is an interval for lucidsoftware/relate#44, right?

these postgres issue make me think we might need separate modules for databases with column types that go beyond what jdbc assumes are available. Writing an interval to postgres requires a call to setObject while passing a PGInterval. I think I'm going to create a sub-project (relate-postgres or something) that deals with these kinds of unique types for postgres. Does anyone have any thoughts on this?

Gregg Hernandez

@gregghz

Also, fwiw, I think it was a mistake to make a uuid column parser since now it's super overloaded and has pretty weird semantics that only partially even map to what lucid does with it. I believe we only ever read a UUID from a byte array or blob column type. We should have just used a col parser for that type and then transformed to UUID in code. It would have made support the postgres UUID column easier

Mark de Jong

@Fristi

The type of the column (created_at) is date time. You can write expressions in WHERE clauses like I did: AGE(now(), created_at) <= interval '5 minutes'

Quill/Slick uses typeclasses to do different type conversions

Might be interesting for you as well

Mark de Jong

@Fristi

datetime = timestamp

Gregg Hernandez

@gregghz

Typeclasses would be perfect except the only way I've found to use them in a string context like sql is via shapeless. It had a pretty significant negative performance impact.

Gregg Hernandez

@gregghz

@Fristi thanks for that info. I believe the problem could be solved by creating an implicit PGInterval => Parameter and then instead of trying to interpolate a Long, with sql"... AGE(now(), created_at) <= interval '$long milliseonds' you could just interpolate the full PGInterval: sql"... AGE(now(), created_at) <= $pgInterval" (you might need the interval function too, I'm not sure). I haven't had a chance to test this. I will as soon as I can but feel free to give it a shot in the meantime.

Gregg Hernandez

@gregghz

  implicit class PGIntervalParameter(value: PGInterval) extends SingleParameter {
    protected def set(stmt: PreparedStatement, i: Int) = stmt.setObject(i, value)
  }

And then you can query like this:

val interval = new PGInterval(s"${sessionDuration.toMillis} milliseconds")
sql"SELECT session_id, user_uuid, device_uuid FROM sessions WHERE session_id = $sessionId AND AGE(now(), created_at) < $interval"

Gregg Hernandez

@gregghz

lucidsoftware/relate#48

Mark de Jong

@Fristi

Thanks for your answer @gregghz.

I'll try soon

And report back :-)

Mark de Jong

@Fristi

That works, I've reported it as well in the issue

Thanks for your support @gregghz

Gregg Hernandez

@gregghz

👍

winry

@fwrq41251

Any one know how to split a sql into many lines?

Use "+" to concat strings bring compile error

Mark Siebert

@msiebert

http://lucidsoftware.github.io/relate/docs/writing-queries.html#query-composition suggests that using + with two sql"" strings should work. Is that not working for you?

also that header on the documentation is all messed up @gregghz

you should fix it with your mad css skillz

James Judd

@jjudd

I'm pretty sure that sql"""<stuff>""" should also work, so you can just use a multiline string.

winry

@fwrq41251

@jjudd works 👍

Mark Siebert

@msiebert

oh yeah, I totally misunderstood your question. Sorry about that

Drew O'Kane

@drewokane

hi, I'm having a bit of trouble with dates in a query. I'm attempting to do something like:

val dateFormat = "YYYY-MM-DD HH:mm:ss"
val start = new DateTime(2016, 1, 1, 0, 1, 1).toString(dateFormat)
sql"select * from measurement where end_interval >= $start limit 10"

Gregg Hernandez

@gregghz

is that a joda date time?

Drew O'Kane

@drewokane

yes it is

Gregg Hernandez

@gregghz

there's no interpolator for that

you also don't want to do toString on it like that

do this:

val start = new DateTime(2016, 1, 1, 0, 1, 1)
sql"select * from measurement where end_interval >= ${start.toDate} limit 10"

we never created a parameter for interpolation of org.joda.time.DateTime because we didn't want to add dependencies to relate. We would probably accept a PR adding direct support to DateTime via a module the way we have postgres support via a module though

Drew O'Kane

@drewokane

hmmm, seems simple enough

doesn't work though:

scala> sql"select * from measurement where end_interval >= ${start.toDate} limit 10"
res25: com.lucidchart.relate.InterpolatedQuery = select * from measurement where end_interval >= ? limit 10

oh wait, nvm

went through

thanks @gregghz

Gregg Hernandez

@gregghz

np!

Murphy Randle

@mrmurphy

Hey friends, I'm just getting into SQL with Scala, and I'm using Relate. I'm running into an interesting situation where I've got this query:

delete from management where key in (?);

the actual source looks like this:

sql"delete from $table where key in ($deleteKeys);"

and $deletedKeys contains a string value

in this case foo

Gregg Hernandez

@gregghz

what is table? you might be subject to an sql syntax error with that usage

Murphy Randle

@mrmurphy

the strange behavior I'm seeing is that foo will sometimes be deleted, and sometimes it will remain while only its content is deleted

it's nondeterministic

oh interesting, it's a custom table

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