记录下一个简单的scala sql DSL
2011-12-22 16:55:01.0
记录下一个简单的scala sql DSL
一个日本人写的DSL 原网址:https://github.com/yuroyoro/Squire
总共两个类,基于twitter的querulous框架
package com.yuroyoro.squire
import java.sql.ResultSet
import scala.collection.mutable.ArrayBuffer
import com.twitter.querulous.evaluator.QueryEvaluator
trait SqlCommand {
val head:Option[SqlCommand]
val command:String
def arg:String
val pms = new ArrayBuffer[Any]
def constract = command format arg
def query:String = head match {
case None => constract
case Some(cmd) => cmd.query + " " + constract
}
def params:ArrayBuffer[Any] = head match{
case None => pms
case Some(cmd) => cmd.params ++ pms
}
override def toString = query
}
trait Selectable extends SqlCommand{
def apply[A](f: ResultSet => A)( implicit qe:QueryEvaluator ):Seq[A] = select( f )( qe )
def select[A](f: ResultSet => A)( implicit qe:QueryEvaluator ): Seq[A] =
qe.select( query , params: _* )(f)
def selectOne[A](f: ResultSet => A)( implicit qe:QueryEvaluator ): Option[A] =
qe.selectOne( query , params: _* )(f)
def count( implicit qe:QueryEvaluator ): Int =
qe.count( query , params: _* )
}
trait Executable extends SqlCommand{
def apply( implicit qe:QueryEvaluator ): Int = execute( qe )
def execute( implicit qe:QueryEvaluator ): Int = qe.execute( query , params: _* )
}
trait SelectConditionale extends Selectable {
def where( cond:Condition ) = new Where( this , cond ) with Selectable with Groupable with Sortable
}
trait ExecuteConditionale extends Executable {
def where( cond:Condition ) = new Where( this , cond ) with Executable
}
trait Groupable extends Selectable{
def group( cond:String ) = new Group( this, cond ) with Sortable
}
trait Sortable extends Selectable {
def order( cond:String ) = new Order( this, cond ) with Selectable
}
case class By( columns:String ) {
def asc = columns + " ASC"
def desc = columns + " DESC"
}
class Select ( val arg:String ) extends SqlCommand {
val head = None
val command = "SELECT %s"
def from( table:String ) = new From( this , table ) with SelectConditionale
}
class From( val h:SqlCommand, val arg:String ) extends SqlCommand {
val head = Some(h)
val command = "FROM %s"
}
class Where( val h:SqlCommand, cond:Condition ) extends SqlCommand{
val head = Some(h)
def arg = cond.condition
pms ++= cond.params
val command = "WHERE %s"
}
class Group( val h:SqlCommand, val arg:String ) extends SqlCommand {
val head = Some(h)
val command = "GROUP BY %s"
}
class Order( val h:SqlCommand, val arg:String ) extends SqlCommand {
val head = Some(h)
val command = "ORDER BY %s"
}
class Insert extends SqlCommand{
val head = None
def arg:String = ""
val command = "INSERT"
def into( table:String ) = new Into( this, table ) with SelectConditionale
def values( values:Any* ) = new Values( this , values: _* ) with Executable
}
class Into( val h:SqlCommand, table:String ) extends SqlCommand{
val head = Some(h)
val command = "INTO %s"
var cols:String = ""
override def arg = table + " " + cols
def apply( columns:String* ) = {
cols = columns.mkString( "(", ",", ")" )
this
}
def values( values:Any* ) = new Values( this , values: _* ) with Executable
}
class Values( val h:SqlCommand, values:Any* ) extends SqlCommand {
val head = Some(h)
val command = "VALUES %s"
pms ++= values
override def arg = Array.make( values.size, "?").mkString( "(", ",", ")" )
}
class Update( val arg:String ) extends SqlCommand{
val head = None
val command = "UPDATE %s"
def set( sets:SetVal* ) = new SetValues( this, sets: _* ) with ExecuteConditionale
}
class SetValues( val h:SqlCommand, sets:SetVal* ) extends SqlCommand {
val head = Some(h)
val command = "SET %s"
var cols:String = ""
pms ++= sets.map{ _.param }
override def arg = sets.mkString(",")
}
case class SetVal( column:String ){
var param:Any = null
def =/( v:Any ) = param = v
override def toString = "%s = ?".format( column )
}