CSJoin.cs :  » Persistence-Frameworks » Vici-CoolStorage » Vici » CoolStorage » C# / CSharp Open Source

#region License
//=============================================================================
// Vici CoolStorage - .NET Object Relational Mapping Library 
//
// Copyright (c) 2004-2009 Philippe Leybaert
//
// Permission is hereby granted, free of charge, to any person obtaining a copy 
// of this software and associated documentation files (the "Software"), to deal 
// in the Software without restriction, including without limitation the rights 
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 
// copies of the Software, and to permit persons to whom the Software is 
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in 
// all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
// IN THE SOFTWARE.
//=============================================================================
#endregion

using System;
using System.Collections.Generic;

namespace Vici.CoolStorage{
  internal enum CSJoinType
  {
    Inner, Left, Right
  }

    internal sealed class CSJoin : IEquatable<CSJoin>
  {
    private string _leftTable;
    private string _rightTable;
        private string _leftAlias;
    private string _rightAlias;
        
    private CSSchema _leftSchema;
    private CSSchema _rightSchema;

    public CSJoinType Type;
    public string LeftColumn;
    public string RightColumn;

    public CSJoin()
    {
            _leftAlias = CSNameGenerator.NextTableAlias;
            _rightAlias = CSNameGenerator.NextTableAlias;
    }

    public CSJoin(CSRelation relation, string sourceAlias)
    {
            Type = CSJoinType.Left;
        
            _leftSchema = relation.Schema;
      _rightSchema = relation.ForeignSchema;

      _leftAlias = sourceAlias;
            _rightAlias = CSNameGenerator.NextTableAlias;

        LeftColumn = relation.LocalKey;
      RightColumn = relation.ForeignKey;
    }

    public string LeftTable 
    { 
      get 
      {
        if (_leftTable != null)
          return _leftTable;
        else if (_leftSchema != null)
          return _leftSchema.TableName;
        else
          return null;
      } 
      set 
      { 
        _leftTable = value; 
      } 
    }

    public string RightTable
    {
      get
      {
        if (_rightTable != null)
          return _rightTable;
        else if (_rightSchema != null)
          return _rightSchema.TableName;
        else
          return null;
      }
      set
      {
        _rightTable = value;
      }
    }

    public CSSchema LeftSchema 
    { 
      get { return _leftSchema; } 
      set { _leftSchema = value; } 
    }

    public CSSchema RightSchema 
    { 
      get { return _rightSchema; } 
      set { _rightSchema = value; } 
    }
        
        public string LeftAlias
        {
            get { return _leftAlias; }
            set { _leftAlias = value; }
        }

        public string RightAlias
        {
            get { return _rightAlias; }
            set { _rightAlias = value; }
        }

    public string JoinExpression
    {
      get
      {
        CSSchema leftSchema = _leftSchema;
        CSSchema rightSchema = _rightSchema;

        if (leftSchema == null)
          leftSchema = rightSchema;
        if (rightSchema == null)
          rightSchema = leftSchema;

        string expr = "";

        switch (Type)
        {
          case CSJoinType.Left: expr = "LEFT JOIN "; break;
          case CSJoinType.Right: expr = "RIGHT JOIN "; break;
          case CSJoinType.Inner: expr = "INNER JOIN "; break;
        }

        expr += rightSchema.DB.QuoteTable(RightTable) + " " + _rightAlias + " ON ";

        expr += _leftAlias + "." + leftSchema.DB.QuoteField(LeftColumn) + " = " + _rightAlias + "." + rightSchema.DB.QuoteField(RightColumn);

        return expr;
      }
    }

        public bool Equals(CSJoin other)
    {
      return other.LeftTable == LeftTable && other.RightTable == RightTable && other.LeftColumn == LeftColumn && other.RightColumn == RightColumn;
    }
  }
}