Slick 3.0 如何更新变量列列表，只有在运行时才知道哪个数字 [英] Slick 3.0 how to update variable column list, which number is know only in Runtime

问题描述

slick 3.0 是否可以更新变量列列表，哪个数字只能在运行时知道?

Is it possible to update variable column list, which number is know only in runtime by slick 3.0?

下面是我想要做的示例(不会编译)

Below is example what I want to do (won't compile)

var q: Query[UserTable, UserTable#TableElementType, Seq] = userTable
var columns = List[Any]()
var values = List[Any]()

if (updateCommands.name.isDefined) {
  columns = q.name :: columns
  values = updateCommands.name.get :: values
}

if (updateCommands.surname.isDefined) {
  columns = q.surname :: columns
  values = updateCommands.surname.get :: values
}
q = q.filter(_.id === updateCommands.id).map(columns).update(values)

推荐答案

这是我在 Slick 3.1 中所做的.我不确定更糟的是，编辑纯 SQL 语句或多个查询.所以我决定采用后者，假设 Postgres 优化器会在单个事务的更新查询中看到相同的 WHERE 子句.我的更新方法是这样的

Here is what I've done in Slick 3.1. I wasn't sure what worse, editing plain SQL statement or multiple queries. So I decided to go with latter assuming Postgres optimizer would see same WHERE clause in update queries of single transaction. My update method looks like this

def updateUser(user: User, obj: UserUpdate): Future[Unit] = {

  val actions = mutable.ArrayBuffer[DBIOAction[Int, NoStream, Write with Transactional]]()
  val query = users.withFilter(_.id === user.id)

  obj.name.foreach(v => actions += query.map(_.name).update(v))
  obj.email.foreach(v => actions += query.map(_.email).update(Option(v)))
  obj.password.foreach(v => actions += query.map(_.pwdHash).update(Option(encryptPassword(v))))

  slickDb.run(DBIO.seq(actions.map(_.transactionally): _*))
}

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