mcs/class/referencesource/System.Data.Entity/System/Data/Query/PlanCompiler/CommandPlan.cs

   1 //---------------------------------------------------------------------
   2 // <copyright file="CommandPlan.cs" company="Microsoft">
   3 //      Copyright (c) Microsoft Corporation.  All rights reserved.
   4 // </copyright>
   5 //
   6 // @owner  Microsoft
   7 // @backupOwner Microsoft
   8 //---------------------------------------------------------------------
   9
  10 using System;
  11 using System.Collections.Generic;
  12 using System.Globalization;
  13 using System.Data.Common;
  14 using md = System.Data.Metadata.Edm;
  15 using cqt = System.Data.Common.CommandTrees;
  16 //using System.Diagnostics; // Please use PlanCompiler.Assert instead of Debug.Assert in this class...
  17
  18 // It is fine to use Debug.Assert in cases where you assert an obvious thing that is supposed
  19 // to prevent from simple mistakes during development (e.g. method argument validation
  20 // in cases where it was you who created the variables or the variables had already been validated or
  21 // in "else" clauses where due to code changes (e.g. adding a new value to an enum type) the default
  22 // "else" block is chosen why the new condition should be treated separately). This kind of asserts are
  23 // (can be) helpful when developing new code to avoid simple mistakes but have no or little value in
  24 // the shipped product.
  25 // PlanCompiler.Assert *MUST* be used to verify conditions in the trees. These would be assumptions
  26 // about how the tree was built etc. - in these cases we probably want to throw an exception (this is
  27 // what PlanCompiler.Assert does when the condition is not met) if either the assumption is not correct
  28 // or the tree was built/rewritten not the way we thought it was.
  29 // Use your judgment - if you rather remove an assert than ship it use Debug.Assert otherwise use
  30 // PlanCompiler.Assert.
  31
  32
  33 //
  34 // A CommandPlan represents the plan for a query.
  35 //
  36 namespace System.Data.Query.PlanCompiler
  37 {
  38     #region CommandInfo
  39
  40     /// <summary>
  41     /// Captures information about a single provider command
  42     /// </summary>
  43     internal sealed class ProviderCommandInfo
  44     {
  45         #region public apis
  46
  47         /// <summary>
  48         /// Internal methods to get the command tree
  49         /// </summary>
  50         internal cqt.DbCommandTree CommandTree
  51         {
  52             get { return _commandTree; }
  53         }
  54         #endregion
  55
  56         #region private state
  57         private cqt.DbCommandTree _commandTree;
  58         private ProviderCommandInfo _parent;
  59         private List<ProviderCommandInfo> _children;
  60         #endregion
  61
  62         #region constructors
  63
  64         /// <summary>
  65         /// Internal constructor for a ProviderCommandInfo object
  66         /// </summary>
  67         /// <param name="commandTree">command tree for the provider command</param>
  68         /// <param name="children">children command infos</param>
  69         internal ProviderCommandInfo(cqt.DbCommandTree commandTree,
  70             List<ProviderCommandInfo> children)
  71         {
  72             _commandTree = commandTree;
  73             _children = children;
  74
  75             if (_children == null)
  76             {
  77                 _children = new List<ProviderCommandInfo>();
  78             }
  79
  80             foreach (ProviderCommandInfo child in _children)
  81             {
  82                 child._parent = this;
  83             }
  84         }
  85         #endregion
  86     }
  87
  88     #endregion
  89 }