如何使用 Scala Slick 表达 Postgres 数组

问题描述

我在 Postgres 9.5 中有一个具有这种结构的表:

I have a table in Postgres 9.5 with this structure:

my_table (id Integer, images_ranks image_rank[]);

其中 image_rank 是:

CREATE TYPE image_rank AS (image_url text, thumbnail_rank integer);

我很难在 Slick (3.1) 中表达类似的东西:

I am struggling to express something like that in Slick (3.1):

case class MyTable (id: Int, imagesRanks: Seq[Option[ImageRank]])

implicit val propertyMyTableResult = GetResult(r => MyTable(r.<<, r.<<)
implicit val propertyImageRankResult = GetResult[Option[ImageRank]] { r => ImageRank(r.<<, r.<<)) }

正确的做法是什么?

更新

这个包装(遵循 n1r3 的答案)目前阻止了我:

This wrap (following the answer from n1r3) is blocking me at the moment:

implicit val ImageRankWrapper: JdbcType[List[ImageRank]] = new SimpleArrayJdbcType[ImageRank]("image_rank[]").to(_.toList)

更新 2

还是不知道哪里出了问题.我已经按照你的建议添加了代码，但它仍然抱怨:

Still not sure what is wrong. I have added the code as you suggested, but it still complains with:

找不到参数 rconv 的隐式值:slick.jdbc.GetResult[database.rows.MyTable].

所以我添加了:

隐式 val myTableResult = GetResult[MyTable](r => MyTable(r.<<, r.<<))

返回:

diverging implicit expansion for type slick.jdbc.GetResult[T1]
starting with object GetStringOption in object GetResult
         r.<<, r.<<))

这是我的配置:

import com.github.tminglei.slickpg._
import database.rows.ImageRank

trait CustomPostgresProfile extends ExPostgresProfile
  with PgArraySupport
  with PgPlayJsonSupport
  with PgPostGISSupport
  with PgEnumSupport
  with PgDate2Support {

  // Use PostgreSQL JSONB support
  def pgjson = "jsonb"

  override val api = MyAPI
  object MyAPI extends API
    with ArrayImplicits
    with JsonImplicits
    with PostGISImplicits
    with DateTimeImplicits {
    implicit val imageRankListTypeMapper =
      new AdvancedArrayJdbcType[ImageRank]("image_rank",
        str => utils.SimpleArrayUtils.fromString[ImageRank](s => {
          val ImageRankRegex = "ImageRank\\((.*),(\\d+)\\)".r
          s match {
            case ImageRankRegex(imageUrl, thumbnailRank) =>
              ImageRank(imageUrl, thumbnailRank.toInt)
            case _ =>
              println(s"$s is not ImageRank")
              ImageRank("", 0)
          }
        })(str).orNull,
        imageRanks => utils.SimpleArrayUtils.mkString[ImageRank](_.toString)(imageRanks)
      ).to(_.toList)
  }
}

object CustomPostgresProfile extends CustomPostgresProfile


abstract class DatabaseProfile(val provider: DatabaseConfigProvider) {
  val config = provider.get[CustomPostgresProfile]
  val profile = config.profile
  val db = config.db
}

trait PropertyDataDatabase {
    self: DatabaseProfile =>
    .....

推荐答案

最好使用这个优秀的库:https://github.com/tminglei/slick-pg

The best would be for you to use this excellent library: https://github.com/tminglei/slick-pg

如果您更愿意自己实现，请查看源代码(https://github.com/tminglei/slick-pg/tree/master/core/src/main/scala/com/github/tminglei/slickpg/array) 并从那里得到你想要的.

If you would rather implement it yourself, have a look at the source code (https://github.com/tminglei/slick-pg/tree/master/core/src/main/scala/com/github/tminglei/slickpg/array) and get what you want from there.

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