mcs/class/referencesource/System.Data.Entity/System/Data/Common/CommandTrees/DbDeleteCommandTree.cs

   1 //---------------------------------------------------------------------
   2 // <copyright file="DbDeleteCommandTree.cs" company="Microsoft">
   3 //      Copyright (c) Microsoft Corporation.  All rights reserved.
   4 // </copyright>
   5 //
   6 // @owner  Microsoft, Microsoft
   7 // @backupOwner Microsoft
   8 //---------------------------------------------------------------------
   9
  10 using System;
  11 using System.Collections.Generic;
  12
  13 using System.Data.Metadata.Edm;
  14 using System.Data.Common.CommandTrees.Internal;
  15 using System.Data.Common.Utils;
  16
  17 namespace System.Data.Common.CommandTrees
  18 {
  19     /// <summary>
  20     /// Represents a single row delete operation expressed as a canonical command tree.
  21     /// </summary>
  22     [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Naming", "CA1709:IdentifiersShouldBeCasedCorrectly", MessageId = "Db")]
  23     public sealed class DbDeleteCommandTree : DbModificationCommandTree
  24     {
  25         private readonly DbExpression _predicate;
  26
  27         internal DbDeleteCommandTree(MetadataWorkspace metadata, DataSpace dataSpace, DbExpressionBinding target, DbExpression predicate)
  28             : base(metadata, dataSpace, target)
  29         {
  30             EntityUtil.CheckArgumentNull(predicate, "predicate");
  31
  32             this._predicate = predicate;
  33         }
  34
  35         /// <summary>
  36         /// Gets an <see cref="DbExpression"/> that specifies the predicate used to determine which members of the target collection should be deleted.
  37         /// </summary>
  38         /// <remarks>
  39         /// The predicate can include only the following elements:
  40         /// <list>
  41         /// <item>Equality expression</item>
  42         /// <item>Constant expression</item>
  43         /// <item>IsNull expression</item>
  44         /// <item>Property expression</item>
  45         /// <item>Reference expression to the target</item>
  46         /// <item>And expression</item>
  47         /// <item>Or expression</item>
  48         /// <item>Not expression</item>
  49         /// </list>
  50         /// </remarks>
  51         public DbExpression Predicate
  52         {
  53             get
  54             {
  55                 return _predicate;
  56             }
  57         }
  58
  59         internal override DbCommandTreeKind CommandTreeKind
  60         {
  61             get { return DbCommandTreeKind.Delete; }
  62         }
  63
  64         internal override bool HasReader
  65         {
  66             get
  67             {
  68                 // a delete command never returns server-gen values, and
  69                 // therefore never returns a reader
  70                 return false;
  71             }
  72         }
  73
  74         internal override void DumpStructure(ExpressionDumper dumper)
  75         {
  76             base.DumpStructure(dumper);
  77
  78             if (this.Predicate != null)
  79             {
  80                 dumper.Dump(this.Predicate, "Predicate");
  81             }
  82         }
  83
  84         internal override string PrintTree(ExpressionPrinter printer)
  85         {
  86             return printer.Print(this);
  87         }
  88     }
  89 }