Slick 2.0.0-M3表定义 - 标记属性的说明

I'm working on migrating to slick 2 but I've come across a class that I can't seem to find anywhere.

我正在努力迁移到光滑2但我遇到了一个我似乎无法在任何地方找到的课程。

package learningSlick

import scala.slick.driver.MySQLDriver.simple._

case class Supplier( snum: String, sname: String, status: Int, city: String )

class Suppliers(tag: Option[String]) extends Table[Supplier](tag, "suppliers") {
  def snum  = column[String]("snum")
  def sname = column[String]("sname")
  def status   = column[Int]("status")
  def city     = column[String]("city")
  def * = snum ~ sname ~ status ~ city <> (Supplier, Supplier.unapply _)
}

The following is the code from the tutorial:

以下是教程中的代码：

import scala.slick.driver.PostgresDriver.simple._

class Suppliers(tag: Tag) extends Table[(String, String, Int, String)](tag, "suppliers") {
    def    snum = column[String]("snum")
    def sname = column[String]("sname")
    def status = column[Int]("status")
    def city = column[String]("city")
    def * = (snum, sname, status, city) 
}

In the definition for Table it says that the Tag is of type Option[String] however in a tutorial I'm going through it just uses a type of Tag. I'm looking for which package this is coming from.

在Table的定义中，它表示Tag的类型为Option [String]，但是在我正在阅读的教程中，它只使用了一种Tag。我正在寻找这个来自哪个包。

1 个解决方案

#1

Checking the definition of Table we can see that it's of type Tag: Table definition Don't know where you read or found that it's of type Option[String].

检查表的定义我们可以看到它的类型为Tag：表定义不知道你在哪里读或发现它的类型为Option [String]。

Clicking on Tag brings up the Tag definition: Tag definition

单击Tag可显示标记定义：标记定义

So to answer your question it's coming from the scala.slick.lifted package.

所以要回答你的问题，它来自scala.slick.lifted包。

You won't be needing to actually create a Tag, because you query with the val suppliers = TableQuery[Suppliers] construct, which takes care of all the Tag related stuff.

您不需要实际创建标记，因为您使用val suppliers = TableQuery [Suppliers]构造进行查询，该构造负责处理所有与Tag相关的内容。

#1