scala – 在Slick中使用DatabaseConfig和Database有什么区别？

On top of the configuration syntax for Database,there is another
layer in the form of DatabaseConfig which allows you to configure a
Slick driver plus a matching Database together. This makes it easy to
abstract over different kinds of database systems by simply changing a
configuration file.

我没有得到这一部分,DatabaseConfig如何使底层数据库系统比数据库方法更抽象？假设,我在以下测试中使用DatabaseConfig：

import org.scalatest.{Matchers,FlatSpec}
import slick.backend.DatabaseConfig
import slick.driver.JdbcProfile
import slick.driver.PostgresDriver.api._

import scala.concurrent.ExecutionContext.Implicits.global

class DatabaseConfigTest extends FlatSpec with Matchers {
  def withDb(test: DatabaseConfig[JdbcProfile] => Any) = {
    val dbConfig = DatabaseConfig.forConfig[JdbcProfile]("abstract")

    try test(dbConfig)
    finally dbConfig.db.close()
  }

  "DatabaseConfig" should "work" in withDb { dbConfig =>
    import Supplier._

    val cities = suppliers.map(_.city)

    dbConfig.db.run(cities.result).map(_.foreach(println))
  }
}

如您所见,如果我将我的底层数据库系统从PostgreSQL更改为MySQL,除了配置更改之外,我还需要更改将postgre API导入mysql的import语句.另一方面,如果我使用数据库：

import org.scalatest.{FlatSpec,Matchers}
import slick.driver.PostgresDriver.api._
import slick.jdbc.JdbcBackend.Database

import scala.concurrent.ExecutionContext.Implicits.global

class DatabaseTest extends FlatSpec with Matchers {
  def withDb(test: Database => Any) = {
    val db = Database.forConfig("default")

    try test(db)
    finally db.close()
  }

  "Supplier names" should "be fetched" in withDb { db =>
    import Supplier._

    val names = suppliers.map(_.name)

    db.run(names.result).map(_.foreach(println))
  }
}

当我使用数据库时,底层数据库上的相同更改将导致两个更改：一个在配置文件中,另一个在源代码中.说了这么多,一种方法比另一种更抽象？我使用DatabaseConfig错了吗？