expression.scala

来自「JAVA 语言的函数式编程扩展」· SCALA 代码 · 共 29 行

/*                     __                                               *\
**     ________ ___   / /  ___     Scala API                            **
**    / __/ __// _ | / /  / _ |    (c) 2003-2007, LAMP/EPFL             **
**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
** /____/\___/_/ |_/____/_/ | |                                         **
**                          |/                                          **
\*                                                                      */

// $Id: Expression.scala 10890 2007-04-30 17:47:18Z michelou $


package scala.dbc.statement


/** An expression that calculates some value from fields. */
abstract class Expression extends Relation {
  
  def fieldTypes: List[DataType] = Nil
  
  /** A SQL-99 compliant string representation of the expression. */
  def sqlString: String = "SELECT " + sqlInnerString
  
  /** A SQL-99 compliant string representation of the relation sub-
   *  statement. This only has a meaning inside another statement.
   */
  def sqlInnerString: String
  
}