There are many similar dao methods in anorm, is it right?

Question

I'm using Play2 with anorm. I think the spirit of anorm is write plain sqls, no magic behind.

But I quickly found I have write a lot of similar dao methods. For example:

case class User(id:Pk[String], username:String, email:String, realname:String, city:String, website:String)

object User {
  val simple = get[Pk[String]]("id") ~ get[String]("username") ~ ... get[String]("website") map {
    case id ~ username ~ ... ~ website = User(id, username, ..., website)
  }
  def findByUsername(username:String) = DB.withConnection { implicit connection =>
     SQL("select * from users where username={username}").on('username->username).as(simple.singleOpt)
  }
  def findByEmail(email:String) = DB.withConnection { implicit connection =>
     SQL("select * from users where email={email}").on('email->email).as(simple.singleOpt)
  }
  def findById(id:String) = DB.withConnection { implicit connection =>
     SQL("select * from users where id={id}").on('id->id).as(simple.singleOpt)
  }
  def findByRealname(keyword:String) = DB.withConnection { implicit connection =>
     SQL("select * from users where realname like {keyword}").on('keyword->"%"+keyword+"%").as(simple *)
  }
  // more similar methods
}

There methods are almost the same, exception the where clause has small difference.

So I created a findWhere() method as:

def findWhere(conditon, values:Any*) = ...

That I can call it in actions:

User.findWhere("id=?", id)
User.findWhere("username=?", username)

It works, but I don't think it's recommended by anorm.

What's the best way to solve this problem?

Answer 1

Why do you believe it is not recommended or ok?

Anorm only cares of receiving a SQL query and parsing the result into a case class. If due to your constraints/design you generate that SQL request dinamically, that makes no difference.

The only issue I see is witht he '?' char, which is nto the way Anorm works. I believe it would me more like:

User.findWhere("username", username)

def findWhere(field: String, value: String) = {
  SQL("select * from users where "+ field +"={"+ field +"}").on(Symbol(field)->value).as(simple.singleOpt)
}

This is a simple example, extend as required.