为什么映射到提升查询中的List会失败＆＃34; Slick不知道如何映射给定类型。＆＃34;？

Question

我试图在Slick提升的查询中映射到List，我收到编译错误：

No matching Shape found.
[error] Slick does not know how to map the given types.
[error] Possible causes: T in Table[T] does not match your * projection. Or you use an unsupported type in a Query (e.g. scala List).
[error]   Required level: scala.slick.lifted.FlatShapeLevel
[error]      Source type: Seq[String]
[error]    Unpacked type: T
[error]      Packed type: G

为什么在非Slick地图操作中，我可以映射到任何类型，而在Slick查询中，我可以映射到简单的Scala类型，但不能映射到Scala List？

Answer 1

尝试

import slick.driver.(yourDB)Driver.api._