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/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / DataEntity / System / Data / Objects / Internal / EntitySqlQueryState.cs / 1305376 / EntitySqlQueryState.cs
//---------------------------------------------------------------------- //// Copyright (c) Microsoft Corporation. All rights reserved. // // // @owner [....] //--------------------------------------------------------------------- using System.Collections.Generic; using System.Data.Common; using System.Data.Common.CommandTrees; using System.Data.Common.CommandTrees.ExpressionBuilder; using System.Data.Common.EntitySql; using System.Data.Common.QueryCache; using System.Data.Common.Utils; using System.Data.EntityClient; using System.Data.Metadata.Edm; using System.Data.Objects.Internal; using System.Diagnostics; namespace System.Data.Objects { ////// ObjectQueryState based on Entity-SQL query text. /// internal sealed class EntitySqlQueryState : ObjectQueryState { ////// The Entity-SQL text that defines the query. /// private readonly string _queryText; ////// Can a Limit subclause be appended to the text of this query? /// private readonly bool _allowsLimit; ////// Initializes a new query EntitySqlQueryState instance. /// /// /// The ObjectContext containing the metadata workspace the query was /// built against, the connection on which to execute the query, and the /// cache to store the results in. Must not be null. /// /// /// The Entity-SQL text of the query /// /// /// The merge option to use when retrieving results if an explicit merge option is not specified /// internal EntitySqlQueryState(Type elementType, string commandText, bool allowsLimit, ObjectContext context, ObjectParameterCollection parameters, Span span) : base(elementType, context, parameters, span) { EntityUtil.CheckArgumentNull(commandText, "commandText"); if (string.IsNullOrEmpty(commandText)) { throw EntityUtil.Argument(System.Data.Entity.Strings.ObjectQuery_InvalidEmptyQuery, "commandText"); } _queryText = commandText; _allowsLimit = allowsLimit; } ////// Determines whether or not the current query is a 'Skip' or 'Sort' operation /// and so would allow a 'Limit' clause to be appended to the current query text. /// ////// internal bool AllowsLimitSubclause { get { return _allowsLimit; } } ///True if the current query is a Skip or Sort expression, or a /// Project expression with a Skip or Sort expression input. ////// Always returns the Entity-SQL text of the implemented ObjectQuery. /// /// Always set to the Entity-SQL text of this ObjectQuery. ///Always returns internal override bool TryGetCommandText(out string commandText) { commandText = this._queryText; return true; } internal override bool TryGetExpression(out System.Linq.Expressions.Expression expression) { expression = null; return false; } protected override TypeUsage GetResultType() { DbExpression query = this.Parse(); return query.ResultType; } internal override ObjectQueryState Includetrue .(ObjectQuery sourceQuery, string includePath) { ObjectQueryState retState = new EntitySqlQueryState(this.ElementType, _queryText, _allowsLimit, this.ObjectContext, ObjectParameterCollection.DeepCopy(this.Parameters), Span.IncludeIn(this.Span, includePath)); this.ApplySettingsTo(retState); return retState; } internal override ObjectQueryExecutionPlan GetExecutionPlan(MergeOption? forMergeOption) { // Metadata is required to generate the execution plan or to retrieve it from the cache. this.ObjectContext.EnsureMetadata(); // Determine the required merge option, with the following precedence: // 1. The merge option specified to Execute(MergeOption) as forMergeOption. // 2. The merge option set via ObjectQuery.MergeOption. // 3. The global default merge option. MergeOption mergeOption = EnsureMergeOption(forMergeOption, this.UserSpecifiedMergeOption); // If a cached plan is present, then it can be reused if it has the required merge option // (since span and parameters cannot change between executions). However, if the cached // plan does not have the required merge option we proceed as if it were not present. ObjectQueryExecutionPlan plan = this._cachedPlan; if (plan != null) { if (plan.MergeOption == mergeOption) { return plan; } else { plan = null; } } // There is no cached plan (or it was cleared), so the execution plan must be retrieved from // the global query cache (if plan caching is enabled) or rebuilt for the required merge option. QueryCacheManager cacheManager = null; EntitySqlQueryCacheKey cacheKey = null; if (this.PlanCachingEnabled) { // Create a new cache key that reflects the current state of the Parameters collection // and the Span object (if any), and uses the specified merge option. cacheKey = new EntitySqlQueryCacheKey( this.ObjectContext.DefaultContainerName, _queryText, (null == this.Parameters ? 0 : this.Parameters.Count), (null == this.Parameters ? null : this.Parameters.GetCacheKey()), (null == this.Span ? null : this.Span.GetCacheKey()), mergeOption, this.ElementType); cacheManager = this.ObjectContext.MetadataWorkspace.GetQueryCacheManager(); ObjectQueryExecutionPlan executionPlan = null; if (cacheManager.TryCacheLookup(cacheKey, out executionPlan)) { plan = executionPlan; } } if (plan == null) { // Either caching is not enabled or the execution plan was not found in the cache DbExpression queryExpression = this.Parse(); Debug.Assert(queryExpression != null, "EntitySqlQueryState.Parse returned null expression?"); DbQueryCommandTree tree = DbQueryCommandTree.FromValidExpression(this.ObjectContext.MetadataWorkspace, DataSpace.CSpace, queryExpression); plan = ObjectQueryExecutionPlan.Prepare(this.ObjectContext, tree, this.ElementType, mergeOption, this.Span, null); // If caching is enabled then update the cache now if (cacheKey != null) { EntitySqlQueryCacheEntry newEntry = new EntitySqlQueryCacheEntry(cacheKey, plan); QueryCacheEntry foundEntry = null; if (cacheManager.TryLookupAndAdd(newEntry, out foundEntry)) { // If TryLookupAndAdd returns 'true' then the entry was already present in the cache when the attempt to add was made. // In this case the existing execution plan should be used. plan = ((EntitySqlQueryCacheEntry)foundEntry).ExecutionPlan; } } } if (this.Parameters != null) { this.Parameters.SetReadOnly(true); } // Update the cached plan with the newly retrieved/prepared plan this._cachedPlan = plan; // Return the execution plan return plan; } internal DbExpression Parse() { List parameters = null; if (this.Parameters != null) { parameters = new List (this.Parameters.Count); foreach (ObjectParameter parameter in this.Parameters) { TypeUsage typeUsage = parameter.TypeUsage; if (null == typeUsage) { // Since ObjectParameters do not allow users to specify 'facets', make // sure that the parameter TypeUsage is not populated with the provider // default facet values. this.ObjectContext.Perspective.TryGetTypeByName( parameter.MappableType.FullName, false /* bIgnoreCase */, out typeUsage); } Debug.Assert(typeUsage != null, "typeUsage != null"); parameters.Add(typeUsage.Parameter(parameter.Name)); } } DbLambda lambda = CqlQuery.CompileQueryCommandLambda( _queryText, // Command Text this.ObjectContext.Perspective, // Perspective null, // Parser options - null indicates 'use default' parameters, // Parameters null // Variables ); Debug.Assert(lambda.Variables == null || lambda.Variables.Count == 0, "lambda.Variables must be empty"); return lambda.Body; } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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