Add view support to the relational model API

Use the new model in the query pipeline

Fixes #12846

src/EFCore.Design/Migrations/Design/CSharpSnapshotGenerator.cs

@@ -62,7 +62,8 @@ public virtual void Generate(string builderName, IModel model, IndentedStringBui
                 CoreAnnotationNames.ChangeTrackingStrategy,
                 CoreAnnotationNames.OwnedTypes,
                 RelationalAnnotationNames.CheckConstraints,
-                RelationalAnnotationNames.Tables);
+                RelationalAnnotationNames.Tables,
+                RelationalAnnotationNames.Views);
 
             if (annotations.Count > 0)
             {
@@ -497,6 +498,7 @@ protected virtual void GeneratePropertyAnnotations([NotNull] IProperty property,
                 annotations,
                 RelationalAnnotationNames.ColumnType,
                 RelationalAnnotationNames.TableColumnMappings,
+                RelationalAnnotationNames.ViewColumnMappings,
                 CoreAnnotationNames.ValueGeneratorFactory,
                 CoreAnnotationNames.PropertyAccessMode,
                 CoreAnnotationNames.ChangeTrackingStrategy,
@@ -787,7 +789,8 @@ protected virtual void GenerateEntityTypeAnnotations(
                 CoreAnnotationNames.DefiningQuery,
                 CoreAnnotationNames.QueryFilter,
                 RelationalAnnotationNames.CheckConstraints,
-                RelationalAnnotationNames.TableMappings);
+                RelationalAnnotationNames.TableMappings,
+                RelationalAnnotationNames.ViewMappings);
 
             if (annotations.Count > 0)
             {

src/EFCore.Design/Migrations/Design/MigrationsCodeGenerator.cs

@@ -244,7 +244,10 @@ private IEnumerable<string> GetAnnotationNamespaces(IEnumerable<IAnnotatable> it
                 RelationalAnnotationNames.CheckConstraints,
                 RelationalAnnotationNames.Tables,
                 RelationalAnnotationNames.TableMappings,
-                RelationalAnnotationNames.TableColumnMappings
+                RelationalAnnotationNames.TableColumnMappings,
+                RelationalAnnotationNames.Views,
+                RelationalAnnotationNames.ViewMappings,
+                RelationalAnnotationNames.ViewColumnMappings
             };
 
             var ignoredAnnotationTypes = new List<string>

src/EFCore.Design/Scaffolding/Internal/CSharpDbContextGenerator.cs

@@ -264,6 +264,7 @@ protected virtual void GenerateOnModelCreating(
             RemoveAnnotation(ref annotations, RelationalAnnotationNames.MaxIdentifierLength);
             RemoveAnnotation(ref annotations, RelationalAnnotationNames.CheckConstraints);
             RemoveAnnotation(ref annotations, RelationalAnnotationNames.Tables);
+            RemoveAnnotation(ref annotations, RelationalAnnotationNames.Views);
             RemoveAnnotation(ref annotations, ScaffoldingAnnotationNames.DatabaseName);
             RemoveAnnotation(ref annotations, ScaffoldingAnnotationNames.EntityTypeErrors);
 
@@ -366,6 +367,7 @@ private void GenerateEntityType(IEntityType entityType, bool useDataAnnotations)
             RemoveAnnotation(ref annotations, RelationalAnnotationNames.Comment);
             RemoveAnnotation(ref annotations, RelationalAnnotationNames.Schema);
             RemoveAnnotation(ref annotations, RelationalAnnotationNames.TableMappings);
+            RemoveAnnotation(ref annotations, RelationalAnnotationNames.ViewMappings);
             RemoveAnnotation(ref annotations, ScaffoldingAnnotationNames.DbSetName);
 
             RemoveAnnotation(ref annotations, RelationalAnnotationNames.ViewDefinition);
@@ -616,6 +618,7 @@ private void GenerateProperty(IProperty property, bool useDataAnnotations)
             RemoveAnnotation(ref annotations, RelationalAnnotationNames.ComputedColumnSql);
             RemoveAnnotation(ref annotations, RelationalAnnotationNames.IsFixedLength);
             RemoveAnnotation(ref annotations, RelationalAnnotationNames.TableColumnMappings);
+            RemoveAnnotation(ref annotations, RelationalAnnotationNames.ViewColumnMappings);
             RemoveAnnotation(ref annotations, ScaffoldingAnnotationNames.ColumnOrdinal);
 
             if (!useDataAnnotations)

src/EFCore.Relational/Extensions/RelationalEntityTypeExtensions.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System.Collections.Generic;
+using System.Linq;
 using JetBrains.Annotations;
 using Microsoft.EntityFrameworkCore.Infrastructure;
 using Microsoft.EntityFrameworkCore.Metadata;
@@ -146,13 +147,29 @@ public static void SetSchema(
                 ?.GetConfigurationSource();
 
         /// <summary>
-        ///     Returns the name of the table to which the entity type is mapped.
+        ///     Returns the tables to which the entity type is mapped.
         /// </summary>
         /// <param name="entityType"> The entity type to get the table name for. </param>
         /// <returns> The name of the table to which the entity type is mapped. </returns>
         public static IEnumerable<ITableMapping> GetTableMappings([NotNull] this IEntityType entityType) =>
             (IEnumerable<ITableMapping>)entityType[RelationalAnnotationNames.TableMappings];
 
+        /// <summary>
+        ///     Returns the views or tables to which the entity type is mapped.
+        /// </summary>
+        /// <param name="entityType"> The entity type to get the table name for. </param>
+        /// <returns> The name of the table to which the entity type is mapped. </returns>
+        public static IEnumerable<ITableMappingBase> GetViewOrTableMappings([NotNull] this IEntityType entityType) =>
+            (IEnumerable<ITableMappingBase>)GetViewMappings(entityType) ?? GetTableMappings(entityType);
+
+        /// <summary>
+        ///     Returns the views to which the entity type is mapped.
+        /// </summary>
+        /// <param name="entityType"> The entity type to get the table name for. </param>
+        /// <returns> The name of the table to which the entity type is mapped. </returns>
+        public static IEnumerable<IViewMapping> GetViewMappings([NotNull] this IEntityType entityType) =>
+            (IEnumerable<IViewMapping>)entityType[RelationalAnnotationNames.ViewMappings];
+
         /// <summary>
         ///     Returns the name of the view to which the entity type is mapped.
         /// </summary>

src/EFCore.Relational/Extensions/RelationalModelExtensions.cs

@@ -61,7 +61,8 @@ public static void SetDefaultSchema(
         /// <param name="model"> The model to get the tables for. </param>
         /// <returns> All the tables mapped in the model. </returns>
         public static IEnumerable<ITable> GetTables([NotNull] this IModel model) =>
-            ((IDictionary<(string, string), Table>)model[RelationalAnnotationNames.Tables]).Values;
+            ((IDictionary<(string, string), Table>)model[RelationalAnnotationNames.Tables])?.Values
+                ?? Enumerable.Empty<ITable>();
 
         /// <summary>
         ///     Gets the table with a given name. Returns <c>null</c> if no table with the given name is defined.
@@ -70,10 +71,39 @@ public static IEnumerable<ITable> GetTables([NotNull] this IModel model) =>
         /// <param name="name"> The name of the table. </param>
         /// <param name="schema"> The schema of the table. </param>
         /// <returns> The table with a given name or <c>null</c> if no table with the given name is defined. </returns>
-        public static ITable FindTable([NotNull] this IModel model, [NotNull] string name, [CanBeNull] string schema) =>
-            ((IDictionary<(string, string), Table>)model[RelationalAnnotationNames.Tables]).TryGetValue((name, schema), out var table)
+        public static ITable FindTable([NotNull] this IModel model, [NotNull] string name, [CanBeNull] string schema)
+        {
+            Table table = null;
+            return ((IDictionary<(string, string), Table>)model[RelationalAnnotationNames.Tables])
+?.TryGetValue((name, schema), out table) == true
                 ? table
                 : null;
+        }
+
+        /// <summary>
+        ///     Returns all the views mapped in the model.
+        /// </summary>
+        /// <param name="model"> The model to get the tables for. </param>
+        /// <returns> All the tables mapped in the model. </returns>
+        public static IEnumerable<IView> GetViews([NotNull] this IModel model) =>
+            ((IDictionary<(string, string), View>)model[RelationalAnnotationNames.Views])?.Values
+                ?? Enumerable.Empty<IView>();
+
+        /// <summary>
+        ///     Gets the view with a given name. Returns <c>null</c> if no view with the given name is defined.
+        /// </summary>
+        /// <param name="model"> The model to get the view for. </param>
+        /// <param name="name"> The name of the view. </param>
+        /// <param name="schema"> The schema of the view. </param>
+        /// <returns> The view with a given name or <c>null</c> if no view with the given name is defined. </returns>
+        public static IView FindView([NotNull] this IModel model, [NotNull] string name, [CanBeNull] string schema)
+        {
+            View view = null;
+            return ((IDictionary<(string, string), View>)model[RelationalAnnotationNames.Views])
+                ?.TryGetValue((name, schema), out view) == true
+                    ? view
+                    : null;
+        }
 
         /// <summary>
         ///     Returns the maximum length allowed for store identifiers.

src/EFCore.Relational/Extensions/RelationalPropertyExtensions.cs

@@ -175,13 +175,29 @@ public static void SetColumnType(
             => property.FindAnnotation(RelationalAnnotationNames.ColumnType)?.GetConfigurationSource();
 
         /// <summary>
-        ///     Returns the columns to which the property is mapped.
+        ///     Returns the table columns to which the property is mapped.
         /// </summary>
         /// <param name="property"> The property. </param>
-        /// <returns> The name of the table to which the entity type is mapped. </returns>
+        /// <returns> The table columns to which the property is mapped. </returns>
         public static IEnumerable<IColumnMapping> GetTableColumnMappings([NotNull] this IProperty property) =>
             (IEnumerable<IColumnMapping>)property[RelationalAnnotationNames.TableColumnMappings];
 
+        /// <summary>
+        ///     Returns the view or table columns to which the property is mapped.
+        /// </summary>
+        /// <param name="property"> The property. </param>
+        /// <returns> The view or table columns to which the property is mapped. </returns>
+        public static IEnumerable<IColumnMappingBase> GetViewOrTableColumnMappings([NotNull] this IProperty property) =>
+            (IEnumerable<IColumnMappingBase>)GetViewColumnMappings(property) ?? GetTableColumnMappings(property);
+
+        /// <summary>
+        ///     Returns the view columns to which the property is mapped.
+        /// </summary>
+        /// <param name="property"> The property. </param>
+        /// <returns> The view columns to which the property is mapped. </returns>
+        public static IEnumerable<IViewColumnMapping> GetViewColumnMappings([NotNull] this IProperty property) =>
+            (IEnumerable<IViewColumnMapping>)property[RelationalAnnotationNames.ViewColumnMappings];
+
         /// <summary>
         ///     Returns the SQL expression that is used as the default value for the column this property is mapped to.
         /// </summary>

src/EFCore.Relational/Metadata/ITable.cs

@@ -30,36 +30,21 @@ public interface ITable : ITableBase
         bool IsMigratable { get; }
 
         /// <summary>
-        ///     Returns a value indicating whether multiple entity types are sharing the rows in the table.
+        ///     The check constraints for this table.
         /// </summary>
-        bool IsSplit { get; }
-
-        /// <summary>
-        ///     Returns the column with a given name. Returns <c>null</c> if no column with the given name is defined.
-        /// </summary>
-        IColumn FindColumn([NotNull] string name);
-
-        /// <summary>
-        ///     Returns the foreign keys for the given entity type that point to other entity types sharing this table.
-        /// </summary>
-        IEnumerable<IForeignKey> GetInternalForeignKeys([NotNull] IEntityType entityType);
-
-        /// <summary>
-        ///     Returns the foreign keys referencing the given entity type from other entity types sharing this table.
-        /// </summary>
-        IEnumerable<IForeignKey> GetReferencingInternalForeignKeys([NotNull] IEntityType entityType);
-
-        /// <summary>
-        ///     Returns the check constraints for this table.
-        /// </summary>
-        IEnumerable<ICheckConstraint> GetCheckConstraints()
+        IEnumerable<ICheckConstraint> CheckConstraints
             => EntityTypeMappings.SelectMany(m => CheckConstraint.GetCheckConstraints(m.EntityType))
                 .Distinct((x, y) => x.Name == y.Name);
 
         /// <summary>
-        ///     Returns the comment for this table.
+        ///     The comment for this table.
         /// </summary>
-        public virtual string GetComment()
+        public virtual string Comment
             => EntityTypeMappings.Select(e => e.EntityType.GetComment()).FirstOrDefault(c => c != null);
+
+        /// <summary>
+        ///     Returns the column with a given name. Returns <c>null</c> if no column with the given name is defined.
+        /// </summary>
+        new IColumn FindColumn([NotNull] string name);
     }
 }

src/EFCore.Relational/Metadata/ITableBase.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using Microsoft.EntityFrameworkCore.Infrastructure;
 
 namespace Microsoft.EntityFrameworkCore.Metadata
@@ -21,6 +22,11 @@ public interface ITableBase : IAnnotatable
         /// </summary>
         string Schema { get; }
 
+        /// <summary>
+        ///     Returns a value indicating whether multiple entity types are sharing the rows in the table.
+        /// </summary>
+        bool IsSplit { get; }
+
         /// <summary>
         ///     The entity type mappings.
         /// </summary>
@@ -30,5 +36,20 @@ public interface ITableBase : IAnnotatable
         ///     The columns defined for this table.
         /// </summary>
         IEnumerable<IColumnBase> Columns { get; }
+
+        /// <summary>
+        ///     Returns the column with a given name. Returns <c>null</c> if no column with the given name is defined.
+        /// </summary>
+        IColumnBase FindColumn([NotNull] string name);
+
+        /// <summary>
+        ///     Returns the foreign keys for the given entity type that point to other entity types sharing this table.
+        /// </summary>
+        IEnumerable<IForeignKey> GetInternalForeignKeys([NotNull] IEntityType entityType);
+
+        /// <summary>
+        ///     Returns the foreign keys referencing the given entity type from other entity types sharing this table.
+        /// </summary>
+        IEnumerable<IForeignKey> GetReferencingInternalForeignKeys([NotNull] IEntityType entityType);
     }
 }

src/EFCore.Relational/Metadata/IView.cs

@@ -0,0 +1,34 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Collections.Generic;
+using JetBrains.Annotations;
+
+namespace Microsoft.EntityFrameworkCore.Metadata
+{
+    /// <summary>
+    ///     Represents a view in the database.
+    /// </summary>
+    public interface IView : ITableBase
+    {
+        /// <summary>
+        ///     The entity type mappings.
+        /// </summary>
+        new IEnumerable<IViewMapping> EntityTypeMappings { get; }
+
+        /// <summary>
+        ///     The columns defined for this view.
+        /// </summary>
+        new IEnumerable<IViewColumn> Columns { get; }
+
+        /// <summary>
+        ///     Returns the column with a given name. Returns <c>null</c> if no column with the given name is defined.
+        /// </summary>
+        new IViewColumn FindColumn([NotNull] string name);
+
+        /// <summary>
+        ///     The view definition or <c>null</c> if this view is not managed by migrations.
+        /// </summary>
+        public string ViewDefinition { get; }
+    }
+}

src/EFCore.Relational/Metadata/IViewColumn.cs

@@ -0,0 +1,23 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Collections.Generic;
+
+namespace Microsoft.EntityFrameworkCore.Metadata
+{
+    /// <summary>
+    ///     Represents a column in a view.
+    /// </summary>
+    public interface IViewColumn : IColumnBase
+    {
+        /// <summary>
+        ///     The containing view.
+        /// </summary>
+        IView View { get; }
+
+        /// <summary>
+        ///     The property mappings.
+        /// </summary>
+        new IEnumerable<IViewColumnMapping> PropertyMappings { get; }
+    }
+}

src/EFCore.Relational/Metadata/IViewColumnMapping.cs

@@ -0,0 +1,21 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+namespace Microsoft.EntityFrameworkCore.Metadata
+{
+    /// <summary>
+    ///     Represents property mapping to a column.
+    /// </summary>
+    public interface IViewColumnMapping : IColumnMappingBase
+    {
+        /// <summary>
+        ///     The target column.
+        /// </summary>
+        new IViewColumn Column { get; }
+
+        /// <summary>
+        ///     The containing view mapping.
+        /// </summary>
+        IViewMapping ViewMapping { get; }
+    }
+}

src/EFCore.Relational/Metadata/IViewMapping.cs

@@ -0,0 +1,23 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Collections.Generic;
+
+namespace Microsoft.EntityFrameworkCore.Metadata
+{
+    /// <summary>
+    ///     Represents entity type mapping to a view.
+    /// </summary>
+    public interface IViewMapping : ITableMappingBase
+    {
+        /// <summary>
+        ///     The target view.
+        /// </summary>
+        IView View { get; }
+
+        /// <summary>
+        ///     The properties mapped to columns on the target view.
+        /// </summary>
+        new IEnumerable<IViewColumnMapping> ColumnMappings { get; }
+    }
+}

src/EFCore.Relational/Metadata/Internal/Column.cs

@@ -22,7 +22,7 @@ public class Column : Annotatable, IColumn
         ///     any release. You should only use it directly in your code with extreme caution and knowing that
         ///     doing so can result in application failures when updating to a new Entity Framework Core release.
         /// </summary>
-        public Column([NotNull] string name, [NotNull] string type, [NotNull] ITable table)
+        public Column([NotNull] string name, [NotNull] string type, [NotNull] Table table)
         {
             Name = name;
             Type = type;

src/EFCore.Relational/Metadata/Internal/ColumnMapping.cs

@@ -24,9 +24,9 @@ public class ColumnMapping : Annotatable, IColumnMapping
         /// </summary>
         public ColumnMapping(
             [NotNull] IProperty property,
-            [NotNull] IColumn column,
+            [NotNull] Column column,
             [NotNull] RelationalTypeMapping typeMapping,
-            [NotNull] ITableMapping tableMapping)
+            [NotNull] TableMapping tableMapping)
         {
             Property = property;
             Column = column;