Code:
/ Dotnetfx_Win7_3.5.1 / Dotnetfx_Win7_3.5.1 / 3.5.1 / DEVDIV / depot / DevDiv / releases / Orcas / NetFXw7 / ndp / fx / src / DataEntity / System / Data / Map / ViewGeneration / QueryRewriting / FragmentQueryProcessor.cs / 1 / FragmentQueryProcessor.cs
using System; using System.Diagnostics; using System.Collections.Generic; using System.Text; using System.Data.Common.Utils; using System.Data.Common.Utils.Boolean; using System.Data.Mapping.ViewGeneration.Structures; using System.Data.Metadata.Edm; using System.Linq; using System.Globalization; namespace System.Data.Mapping.ViewGeneration.QueryRewriting { using BoolDomainConstraint = DomainConstraint; internal class FragmentQueryProcessor : TileQueryProcessor { private FragmentQueryKB _kb; public FragmentQueryProcessor(FragmentQueryKB kb) { _kb = kb; } internal static FragmentQueryProcessor Merge(FragmentQueryProcessor qp1, FragmentQueryProcessor qp2) { FragmentQueryKB mergedKB = new FragmentQueryKB(); mergedKB.AddKnowledgeBase(qp1.KnowledgeBase); mergedKB.AddKnowledgeBase(qp2.KnowledgeBase); return new FragmentQueryProcessor(mergedKB); } internal FragmentQueryKB KnowledgeBase { get { return _kb; } } // resulting query contains an intersection of attributes internal override FragmentQuery Union(FragmentQuery q1, FragmentQuery q2) { HashSet attributes = new HashSet (q1.Attributes); attributes.IntersectWith(q2.Attributes); BoolExpression condition = BoolExpression.CreateOr(q1.Condition, q2.Condition); return FragmentQuery.Create(attributes, condition); } internal bool IsDisjointFrom(FragmentQuery q1, FragmentQuery q2) { return !IsSatisfiable(Intersect(q1, q2)); } internal bool IsContainedIn(FragmentQuery q1, FragmentQuery q2) { return !IsSatisfiable(Difference(q1, q2)); } internal bool IsEquivalentTo(FragmentQuery q1, FragmentQuery q2) { return IsContainedIn(q1, q2) && IsContainedIn(q2, q1); } internal override FragmentQuery Intersect(FragmentQuery q1, FragmentQuery q2) { HashSet attributes = new HashSet (q1.Attributes); attributes.IntersectWith(q2.Attributes); BoolExpression condition = BoolExpression.CreateAnd(q1.Condition, q2.Condition); return FragmentQuery.Create(attributes, condition); } internal override FragmentQuery Difference(FragmentQuery qA, FragmentQuery qB) { return FragmentQuery.Create(qA.Attributes, BoolExpression.CreateAndNot(qA.Condition, qB.Condition)); } internal override bool IsSatisfiable(FragmentQuery query) { return IsSatisfiable(query.Condition); } private bool IsSatisfiable(BoolExpression condition) { // instantiate conversion context for each check - gives better performance BoolExpression conditionUnderKB = condition.Create( new AndExpr (_kb.KbExpression, condition.Tree)); var context = IdentifierService .Instance.CreateConversionContext(); var converter = new Converter (conditionUnderKB.Tree, context); bool isSatisfiable = converter.Vertex.IsZero() == false; return isSatisfiable; } // creates "derived" views that may be helpful for answering the query // for example, view = SELECT ID WHERE B=2, query = SELECT ID,B WHERE B=2 // Created derived view: SELECT ID,B WHERE B=2 by adding the attribute whose value is determined by the where clause to projected list internal override FragmentQuery CreateDerivedViewBySelectingConstantAttributes(FragmentQuery view) { HashSet newProjectedAttributes = new HashSet (); // collect all variables from the view IEnumerable > variables = view.Condition.Variables; foreach (DomainVariable var in variables) { OneOfConst variableCondition = var.Identifier as OneOfConst; if (variableCondition != null) { // Is this attribute not already projected? MemberPath conditionMember = variableCondition.Slot.MemberPath; // Iterating through the variable domain var.Domain could be wasteful // Instead, consider the actual condition values on the variable. Usually, they don't get repeated (if not, we could cache and check) CellConstantDomain conditionValues = variableCondition.Values; if (false == view.Attributes.Contains(conditionMember)) { foreach (CellConstant value in conditionValues.Values) { // construct constraint: X = value DomainConstraint constraint = new DomainConstraint (var, new Set (new CellConstant[] { value }, CellConstant.EqualityComparer)); // is this constraint implied by the where clause? BoolExpression exclusion = view.Condition.Create( new AndExpr >(view.Condition.Tree, new NotExpr >(new TermExpr >(constraint)))); bool isImplied = false == IsSatisfiable(exclusion); if (isImplied) { // add this variable to the projection, if it is used in the query newProjectedAttributes.Add(conditionMember); } } } } } if (newProjectedAttributes.Count > 0) { newProjectedAttributes.UnionWith(view.Attributes); FragmentQuery derivedView = new FragmentQuery(String.Format(CultureInfo.InvariantCulture, "project({0})", view.Description), view.FromVariable, newProjectedAttributes, view.Condition); return derivedView; } return null; } public override string ToString() { return _kb.ToString(); } #region Private class AttributeSetComparator private class AttributeSetComparator : IEqualityComparer > { internal static readonly AttributeSetComparator DefaultInstance = new AttributeSetComparator(); #region IEqualityComparer > Members public bool Equals(HashSet x, HashSet y) { return x.SetEquals(y); } public int GetHashCode(HashSet attrs) { int hashCode = 123; foreach (MemberPath attr in attrs) { hashCode += MemberPath.EqualityComparer.GetHashCode(attr) * 7; } return hashCode; } #endregion } #endregion } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. All rights reserved. using System; using System.Diagnostics; using System.Collections.Generic; using System.Text; using System.Data.Common.Utils; using System.Data.Common.Utils.Boolean; using System.Data.Mapping.ViewGeneration.Structures; using System.Data.Metadata.Edm; using System.Linq; using System.Globalization; namespace System.Data.Mapping.ViewGeneration.QueryRewriting { using BoolDomainConstraint = DomainConstraint ; internal class FragmentQueryProcessor : TileQueryProcessor { private FragmentQueryKB _kb; public FragmentQueryProcessor(FragmentQueryKB kb) { _kb = kb; } internal static FragmentQueryProcessor Merge(FragmentQueryProcessor qp1, FragmentQueryProcessor qp2) { FragmentQueryKB mergedKB = new FragmentQueryKB(); mergedKB.AddKnowledgeBase(qp1.KnowledgeBase); mergedKB.AddKnowledgeBase(qp2.KnowledgeBase); return new FragmentQueryProcessor(mergedKB); } internal FragmentQueryKB KnowledgeBase { get { return _kb; } } // resulting query contains an intersection of attributes internal override FragmentQuery Union(FragmentQuery q1, FragmentQuery q2) { HashSet attributes = new HashSet (q1.Attributes); attributes.IntersectWith(q2.Attributes); BoolExpression condition = BoolExpression.CreateOr(q1.Condition, q2.Condition); return FragmentQuery.Create(attributes, condition); } internal bool IsDisjointFrom(FragmentQuery q1, FragmentQuery q2) { return !IsSatisfiable(Intersect(q1, q2)); } internal bool IsContainedIn(FragmentQuery q1, FragmentQuery q2) { return !IsSatisfiable(Difference(q1, q2)); } internal bool IsEquivalentTo(FragmentQuery q1, FragmentQuery q2) { return IsContainedIn(q1, q2) && IsContainedIn(q2, q1); } internal override FragmentQuery Intersect(FragmentQuery q1, FragmentQuery q2) { HashSet attributes = new HashSet (q1.Attributes); attributes.IntersectWith(q2.Attributes); BoolExpression condition = BoolExpression.CreateAnd(q1.Condition, q2.Condition); return FragmentQuery.Create(attributes, condition); } internal override FragmentQuery Difference(FragmentQuery qA, FragmentQuery qB) { return FragmentQuery.Create(qA.Attributes, BoolExpression.CreateAndNot(qA.Condition, qB.Condition)); } internal override bool IsSatisfiable(FragmentQuery query) { return IsSatisfiable(query.Condition); } private bool IsSatisfiable(BoolExpression condition) { // instantiate conversion context for each check - gives better performance BoolExpression conditionUnderKB = condition.Create( new AndExpr (_kb.KbExpression, condition.Tree)); var context = IdentifierService .Instance.CreateConversionContext(); var converter = new Converter (conditionUnderKB.Tree, context); bool isSatisfiable = converter.Vertex.IsZero() == false; return isSatisfiable; } // creates "derived" views that may be helpful for answering the query // for example, view = SELECT ID WHERE B=2, query = SELECT ID,B WHERE B=2 // Created derived view: SELECT ID,B WHERE B=2 by adding the attribute whose value is determined by the where clause to projected list internal override FragmentQuery CreateDerivedViewBySelectingConstantAttributes(FragmentQuery view) { HashSet newProjectedAttributes = new HashSet (); // collect all variables from the view IEnumerable > variables = view.Condition.Variables; foreach (DomainVariable var in variables) { OneOfConst variableCondition = var.Identifier as OneOfConst; if (variableCondition != null) { // Is this attribute not already projected? MemberPath conditionMember = variableCondition.Slot.MemberPath; // Iterating through the variable domain var.Domain could be wasteful // Instead, consider the actual condition values on the variable. Usually, they don't get repeated (if not, we could cache and check) CellConstantDomain conditionValues = variableCondition.Values; if (false == view.Attributes.Contains(conditionMember)) { foreach (CellConstant value in conditionValues.Values) { // construct constraint: X = value DomainConstraint constraint = new DomainConstraint (var, new Set (new CellConstant[] { value }, CellConstant.EqualityComparer)); // is this constraint implied by the where clause? BoolExpression exclusion = view.Condition.Create( new AndExpr >(view.Condition.Tree, new NotExpr >(new TermExpr >(constraint)))); bool isImplied = false == IsSatisfiable(exclusion); if (isImplied) { // add this variable to the projection, if it is used in the query newProjectedAttributes.Add(conditionMember); } } } } } if (newProjectedAttributes.Count > 0) { newProjectedAttributes.UnionWith(view.Attributes); FragmentQuery derivedView = new FragmentQuery(String.Format(CultureInfo.InvariantCulture, "project({0})", view.Description), view.FromVariable, newProjectedAttributes, view.Condition); return derivedView; } return null; } public override string ToString() { return _kb.ToString(); } #region Private class AttributeSetComparator private class AttributeSetComparator : IEqualityComparer > { internal static readonly AttributeSetComparator DefaultInstance = new AttributeSetComparator(); #region IEqualityComparer > Members public bool Equals(HashSet x, HashSet y) { return x.SetEquals(y); } public int GetHashCode(HashSet attrs) { int hashCode = 123; foreach (MemberPath attr in attrs) { hashCode += MemberPath.EqualityComparer.GetHashCode(attr) * 7; } return hashCode; } #endregion } #endregion } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. All rights reserved.
Link Menu
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- XmlDocumentSchema.cs
- BookmarkOptionsHelper.cs
- MediaTimeline.cs
- StreamSecurityUpgradeProvider.cs
- QueryIntervalOp.cs
- ColorComboBox.cs
- XmlSchemaElement.cs
- ToolboxItemCollection.cs
- _UncName.cs
- WebBrowserProgressChangedEventHandler.cs
- StorageAssociationTypeMapping.cs
- ImmutableObjectAttribute.cs
- XmlAttributeOverrides.cs
- AnnotationService.cs
- CommonXSendMessage.cs
- ProfileParameter.cs
- VBIdentifierDesigner.xaml.cs
- SelectionProcessor.cs
- Keywords.cs
- SqlAggregateChecker.cs
- ValueUnavailableException.cs
- GatewayDefinition.cs
- OleStrCAMarshaler.cs
- FileDetails.cs
- StringDictionary.cs
- WindowsStatusBar.cs
- DataGridViewComboBoxColumn.cs
- EventProviderTraceListener.cs
- NodeInfo.cs
- IntegerValidator.cs
- HttpDebugHandler.cs
- ConfigXmlComment.cs
- SignerInfo.cs
- MediaScriptCommandRoutedEventArgs.cs
- DataViewManager.cs
- DataGridViewComboBoxColumn.cs
- FixedSOMSemanticBox.cs
- CompilationSection.cs
- WorkflowService.cs
- HttpStreams.cs
- DictionaryContent.cs
- Ray3DHitTestResult.cs
- Transaction.cs
- DataServiceKeyAttribute.cs
- TCEAdapterGenerator.cs
- CodeBlockBuilder.cs
- VirtualDirectoryMappingCollection.cs
- ProfileInfo.cs
- ThemeInfoAttribute.cs
- CompositeDuplexBindingElement.cs
- FileLogRecordEnumerator.cs
- SystemNetHelpers.cs
- TextServicesContext.cs
- XmlDocumentFragment.cs
- TreeViewItemAutomationPeer.cs
- EntityDataSourceSelectingEventArgs.cs
- ColumnBinding.cs
- EventDrivenDesigner.cs
- XmlSchemaGroup.cs
- MailDefinition.cs
- TextOnlyOutput.cs
- FormatSettings.cs
- PopupRootAutomationPeer.cs
- SqlRewriteScalarSubqueries.cs
- ClientScriptManager.cs
- WsdlHelpGeneratorElement.cs
- TableItemPatternIdentifiers.cs
- OracleMonthSpan.cs
- _IPv6Address.cs
- OdbcException.cs
- AsynchronousChannelMergeEnumerator.cs
- LinqDataSourceContextData.cs
- ProfilePropertySettings.cs
- Page.cs
- CompilerWrapper.cs
- FixUp.cs
- BaseInfoTable.cs
- UxThemeWrapper.cs
- LayeredChannelListener.cs
- SerializerDescriptor.cs
- log.cs
- ApplicationContext.cs
- ExpressionVisitorHelpers.cs
- ObjectDataSourceDisposingEventArgs.cs
- FontFamily.cs
- TextBox.cs
- GatewayDefinition.cs
- EncoderReplacementFallback.cs
- NamespaceExpr.cs
- OperandQuery.cs
- EndpointDispatcher.cs
- FullTrustAssemblyCollection.cs
- InputChannelAcceptor.cs
- AssemblyBuilder.cs
- TraceHelpers.cs
- ProcessHost.cs
- TextRunTypographyProperties.cs
- GlyphRun.cs
- StorageRoot.cs
- FixedSOMLineRanges.cs