ZIO Quill: How to generalize operations shared by different entities?-CodePudding

Let's say we have two following case classes:

case class Person(name:String, age:Int, createdAt:LocalDate, lastModified:LocalDate)
case class Address(street:String, zip:Int, createdAt:LocalDate, lastModified:LocalDate)

I want to be able to do as follows:

for {
    p <- query[Person]
           .changedAfter(lift(LocalDate.of(2022,1,1)))
    a <- query[Address].join(a => a.ownerId == p.id)
            .changedAfter(lift(LocalDate.of(2022,1,1)))
} yield (p, a)

Where .changedAfter() will work for any entity containing createdAt and lastModified fields.

How would I go on to create such a modification?

CodePudding user response：

Your can create a extension method like this.

import io.getquill._
import java.time._

val ctx = new SqlMirrorContext(PostgresDialect, SnakeCase)

import ctx._

trait EntityLike {
  val createAt: LocalDate
  val lastModified: LocalDate
}

case class Person(name: String, age: Int, createAt: LocalDate, lastModified: LocalDate) extends EntityLike


implicit class EntityOps[A <: EntityLike](q: Query[A]) {
  val changeAfter = quote { (d: LocalDate) =>
    q.filter(e => infix"${e.createAt} < ${d}".as[Boolean])
  }
}
val d = LocalDate.of(2000, 1, 1)
val m = ctx.run(query[Person].changeAfter(lift(d)))

println(m)