Skunk - Scala - 多参数查询出错

Question

我在使用下面的代码时遇到错误

import br.com.gbtech.model.PaymentRequestItem
import cats.effect.{IO, Resource}
import skunk.codec.all.*
import skunk.implicits.*
import skunk.{Query, Session, ~}

  val query: Query[(String *: Int), ValueObject] =
    sql"""
      SELECT field1, field2
      FROM   sample_table
      WHERE  field1 = $text
      AND field2 = $int4
    """.query(ValueObject.decoder)

  database.use(s => s.option(query)((param1, param2)))

解码器在这里：

case class ValueObject(field1: Int, field2: String)

object ValueObject {
  val decoder: Decoder[ValueObject] =
    (int4 ~ varchar).map { case (f1,  f2) => ValueObject(f1, f2) }
}

错误是：

type mismatch;
 found   : skunk.Query[String *: Int *: org.typelevel.twiddles.EmptyTuple,br.com.ValueObject]
    (which expands to)  skunk.Query[String :: Int :: shapeless.HNil,br.com.ValueObject]
 required: skunk.Query[String *: Int,br.com.ValueObject]
    (which expands to)  skunk.Query[String :: Int,br.com.ValueObject]
        """.query(ValueObject.decoder)

问题究竟出在哪里？

Answer 1

解决方案：

• 修复导入

import skunk.codec.all.*
import skunk.implicits.*
import skunk.*

• 修复查询类型，如此处
所述

Query[String *: Int *: EmptyTuple, ValueObject]

• 修复解码器

val decoder: Decoder[ValueObject] =
  (int4 ~ varchar).map { case (f1, f2) =>
    ValueObject(f1, f2) 
  }

Answer 2

版本：

• 臭鼬：0.6.0
• 猫：2.10.0
• 猫效果：3.4.8

import skunk.codec.all.{int4, varchar}

object Dto {
case class ValueObject(field1: Int, field2: String)
  object ValueObject {
    val codec: Codec[ValueObject] = (int4 *: varchar).to[ValueObject]
  }
}

import skunk._
import skunk.implicits._
import Dto._

object ValueObjectSql {
  val query: Query[String *: Int *: EmptyTuple, ValueObject] =
    sql"""
      SELECT field1, field2
      FROM sample_table
      WHERE field2 = $varchar
      AND field1 = $int4
    """.query(ValueObject.codec)
    }

import cats.effect.Resource
import cats.effect.kernel.MonadCancelThrow
import skunk._
import Dto._
import ValueObjectSql._

trait ValueObjectRepository[F[_]] {
  def findValue(field1: Int, field2: String): F[Option[ValueObject]]
}

object ValueObjectRepository {
  def make[F[_]: MonadCancelThrow](
      implicit
      session: Resource[F, Session[F]]
    ): ValueObjectRepository[F] = new ValueObjectRepository[F] {


    override def findValue(field1: Int, field2: String): F[Option[ValueObject]] =
      session.use(s => s.option(query)(field2 *: field1 *: EmptyTuple))
  }
}