ProviderCommandInfoUtils.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / DataEntity / System / Data / Query / PlanCompiler / ProviderCommandInfoUtils.cs / 1305376 / ProviderCommandInfoUtils.cs
                        

                        
                            //---------------------------------------------------------------------- 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// 
// @owner  [....]
// @backupOwner [....] 
//--------------------------------------------------------------------- 

using System; 
using System.Collections.Generic;
//using System.Diagnostics; // Please use PlanCompiler.Assert instead of Debug.Assert in this class...

using System.Data.Common.CommandTrees; 
using System.Data.Common;
using md = System.Data.Metadata.Edm; 
using System.Data.Query.InternalTrees; 
using System.Data.Query.PlanCompiler;
 
namespace System.Data.Query.PlanCompiler
{
    /// 
    /// Helper class for creating a ProviderCommandInfo given an Iqt Node. 
    /// 
    internal static class ProviderCommandInfoUtils 
    { 
        #region Public Methods
 
        /// 
        /// Creates a ProviderCommandInfo for the given node.
        /// This method should be called when the keys, foreign keys and sort keys are known ahead of time.
        /// Typically it is used when the original command is factored into multiple commands. 
        /// 
        /// The owning command, used for creating VarVecs, etc 
        /// The root of the sub-command for which a ProviderCommandInfo should be generated 
        /// A list of ProviderCommandInfos that were created for the child sub-commands.
        /// The resulting ProviderCommandInfo 
        internal static ProviderCommandInfo Create(
            Command command,
            Node node,
            List children) 
        {
            PhysicalProjectOp projectOp = node.Op as PhysicalProjectOp; 
            PlanCompiler.Assert(projectOp != null, "Expected root Op to be a physical Project"); 

            // build up the CQT 
            DbCommandTree ctree = CTreeGenerator.Generate(command, node);
            DbQueryCommandTree cqtree = ctree as DbQueryCommandTree;
            PlanCompiler.Assert(cqtree != null, "null query command tree");
 
            // Get the rowtype for the result cqt
            md.CollectionType collType = TypeHelpers.GetEdmType(cqtree.Query.ResultType); 
            PlanCompiler.Assert(md.TypeSemantics.IsRowType(collType.TypeUsage), "command rowtype is not a record"); 

            // Build up a mapping from Vars to the corresponding output property/column 
            Dictionary outputVarMap = BuildOutputVarMap(projectOp, collType.TypeUsage);

            return new ProviderCommandInfo(ctree, children);
        } 

        ///  
        /// Creates a ProviderCommandInfo for the given node. 
        /// This method should be called when the keys and the sort keys are not known ahead of time.
        /// Typically it is used when there is only one command, that is no query factoring is done. 
        /// This method also has the option of pulling up keys and sort information.
        /// 
        /// The owning command, used for creating VarVecs, etc
        /// The root of the sub-command for which a ProviderCommandInfo should be generated 
        /// The resulting ProviderCommandInfo
        internal static ProviderCommandInfo Create( 
            Command command, 
            Node node)
        { 
            return Create(
                command,
                node,
                new List() //children 
                );
        } 
        #endregion 

        #region Private Methods 
        /// 
        /// Build up a mapping from Vars to the corresponding property of the output row type
        /// 
        /// the physical projectOp 
        /// output type
        /// a map from Vars to the output type member 
        private static Dictionary BuildOutputVarMap(PhysicalProjectOp projectOp, md.TypeUsage outputType) 
        {
            Dictionary outputVarMap = new Dictionary(); 

            PlanCompiler.Assert(md.TypeSemantics.IsRowType(outputType), "PhysicalProjectOp result type is not a RowType?");

            IEnumerator propertyEnumerator = TypeHelpers.GetEdmType(outputType).Properties.GetEnumerator(); 
            IEnumerator varEnumerator = projectOp.Outputs.GetEnumerator();
            while (true) 
            { 
                bool foundProp = propertyEnumerator.MoveNext();
                bool foundVar = varEnumerator.MoveNext(); 
                if (foundProp != foundVar)
                {
                    throw EntityUtil.InternalError(EntityUtil.InternalErrorCode.ColumnCountMismatch, 1);
                } 
                if (!foundProp)
                { 
                    break; 
                }
                outputVarMap[varEnumerator.Current] = propertyEnumerator.Current; 
            }
            return outputVarMap;
        }
 
        #endregion
    } 
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.

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