I think I am still not grasping how to use groupBy
val balanceCreditDebitWithPersonQuery =
creditQ
.groupBy(r => (r._1, r._2, r._3, r._4))
.map{
case (key, groupValue) => key -> groupValue.map(_._5).sum //sum returns 0 if all values of database are null
}.sortBy(_._1._1)
.join(
debitQ
.groupBy(r => (r._1, r._2, r._3, r._4))
.map{
case (key, groupValue) => key -> groupValue.map(_._5).sum
}.sortBy(_._1._1)
).on(_._1._1 === _._1._1)
.map(r => (r._1._1._2, r._1._1._3, r._1._1._4, r._1._2, r._2._2, (r._1._2 - r._2._2))).resultI want to group by the first four columns of each table: .groupBy(r => (r._1, r._2, r._3, r._4))
and use the last column to sum over it: groupValue.map(_._5).sum
groupBy works roughly the same as for usual standard collection. The difference is that you
- can't groupBy on absolutely anything, you have to group by on a "primitive" value, or something with a primary key
- you have to go back to a "flat" structure by calling map.
maybe 1. is not fullfilled in your case. What does it say that is not working out for you? (also you perhaps have to destructure de "key", but I'm not sure right now)
Hello @here, I have a question regarding the migration of slick from 2.0.2 to 3.0.0.
in slick 2.0.0 I have:
def forInsert = (name, fullName.orEmpty, email.orEmpty, password, active)
private lazy val addUserC = users.map(_.forInsert).insertInvokerHow can I migrate insertInvoker to 3.0.0 ?
var url = getClass.getResource("/database/data.db").getFile, however, client projects referencing this library are not able to load the file correctly. Do you know how I can package binary db file with my library?
hi all, I recently hit a performance issue with slick, but I think it's due to how we structure our queries
to support soft-deletion, we have an active column in many tables. since we typically only want active records, we added a shorthand for that:
lazy val baseQuery = TableQuery[MyTable]
lazy val query = baseQuery.filter(_.active)The problem is that when we join a table against this like otherTable.join(myTable.query).on(_.foreignKeyId === _.id) it generates sql that "eagerly" applies the where active in a subquery inside the join, which results in more rows scanned
Does anyone recommend a pattern where we can continue to use query like this so we don't have to remember to filter for active, but also don't have to worry about joins being worse?
Then i have problem with my code:
val appEC = scala.concurrent.ExecutionContext.Implicits.global
val databaseEC = database.executor.executionContext
val requestCount = 30
def update(id: Long)(ex: ExecutionContext) = {
val action = selectByIdAction(id).flatMap(x => updateAction(x))(ex)
database.run(action.transactionally)
}
Future.sequence((1 to requestCount).map(_ => update(someId)(databaseEC))) //works fine
Future.sequence((1 to requestCount).map(_ => update(someId)(appEC))) //doesn't work, deadlockit happens when requestCount > numThreads of AsyncExecutor
I use https://github.com/tototoshi/sbt-slick-codegen to generate my Tables.scala which I then intend to commit to git.
I noticed that the database name is also part of the generated source code Some("acme").
[...]
class SomeTable(_tableTag: Tag) extends profile.api.Table[FlywaySchemaHistoryRow](_tableTag, Some("acme"), "some_table")
[...]Since production code might run against a different database name, is that an issue? Is there some way to not generate the database name? If so, are there any downsides?
protected val propertiesForProduct = for {
(storeId, productIds) <- Parameters[(Long, Set[Int])]
relation <- productCategories.filter(_.storeId === storeId && product.id in productIds)
} yield (relation.productId, relation.categoryId)
Wondering about this issue as I've encountered it, is there any way to go around this? Only way I figured out is to change Postgres time to varchar and then have a custom mapper, which of course isn't optimal if I would have to use some internal time operations.
import slick.jdbc.PostgresProfile.api._
val formatter: DateTimeFormatter = DateTimeFormatter.ISO_LOCAL_TIME
implicit val localTimeColumnType: JdbcType[LocalTime] with BaseTypedType[LocalTime] = MappedColumnType.base[LocalTime, String](
{ b => formatter.format(b) }, // map LocalTime to String
{ i => LocalTime.parse(i) } // map String to LocalTime
)
....
def time = column[LocalTime]("time")(localTimeColumnType)With custom mapper it doesn't work if I have used type time in schema, because then I'm getting following error from Postgres:
ERROR: column "time" is of type time without time zone but expression is of type character varying Hint: You will need to rewrite or cast the expression.
Hi guys! I'm trying to connect to a MySQL database following Slick Documentation
But I keep running into the same problem
com.zaxxer.hikari.pool.HikariPool HikariPool-1 - Exception during pool initialization. com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure\nThe last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
Does it have something to do with mysql-connector version? Currently using 6.0.6 (according to documentation)
1 reply
booking.id
}.map {
case (id, group) =>
(id, group.size, group.map { obj =>
obj.cost.amount
}.sum)
}
def sequentializeFutures[A, B](l: Iterable[A])(fn: A => Future[B])(implicit ec: ExecutionContext): Future[List[B]] =
l.foldLeft(Future(List.empty[B])) { (previousFuture, next) =>
for {
previousResults <- previousFuture
next <- fn(next)
} yield previousResults :+ next
}
In particular, you can do things like this
val myTable = TableQuery[Stuff]
val onlyActiveStuff = myTable.filter(_.active)and use onlyActiveStuff throughout your application freely.