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InsertIfNotExists.scala
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InsertIfNotExists.scala
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import slick.driver.H2Driver.api._
import scala.concurrent.ExecutionContext.Implicits.global
import scala.concurrent.Await
import scala.concurrent.duration.Duration
object InsertIfNotExists extends App {
val users = TableQuery[Users]
def insertIfNotExists(name: String) = users.forceInsertQuery {
val exists = (for (u <- users if u.name === name.bind) yield u).exists
val insert = (name.bind, None) <> (User.apply _ tupled, User.unapply)
for (u <- Query(insert) if !exists) yield u
}
val db = Database.forURL(
url = "jdbc:h2:mem:test",
keepAliveConnection = true
)
try {
val sql = insertIfNotExists("dummy").statements.head
println("Generated SQL: " + sql)
Await.result(db.run(DBIO.seq(
users.schema.create,
// insert two different users named Bob, each with a unique auto-generated ID
users += User("Bob"),
users += User("Bob"),
// this will do nothing because user "Bob" already exists
insertIfNotExists("Bob"),
// insert a new user "Fred"
insertIfNotExists("Fred"),
// this will do nothing because user "Fred" already exists
insertIfNotExists("Fred"),
// we should end up with 3 users
users.result.map(println)
)), Duration.Inf)
} finally db.close()
}