Implement JSON_CONTAINS() for primitive collections

src/EFCore.Relational/Storage/JsonTypeMapping.cs

@@ -18,24 +18,24 @@ namespace Microsoft.EntityFrameworkCore.Storage;
 ///     See <see href="https://aka.ms/efcore-docs-providers">Implementation of database providers and extensions</see>
 ///     for more information and examples.
 /// </remarks>
-public abstract class JsonTypeMapping : RelationalTypeMapping
+public abstract class StructuralJsonTypeMapping : RelationalTypeMapping
 {
     /// <summary>
-    ///     Initializes a new instance of the <see cref="JsonTypeMapping" /> class.
+    ///     Initializes a new instance of the <see cref="StructuralJsonTypeMapping" /> class.
     /// </summary>
     /// <param name="storeType">The name of the database type.</param>
     /// <param name="clrType">The .NET type.</param>
     /// <param name="dbType">The <see cref="DbType" /> to be used.</param>
-    protected JsonTypeMapping(string storeType, Type clrType, DbType? dbType)
+    protected StructuralJsonTypeMapping(string storeType, Type clrType, DbType? dbType)
         : base(storeType, clrType, dbType)
     {
     }
 
     /// <summary>
-    ///     Initializes a new instance of the <see cref="JsonTypeMapping" /> class.
+    ///     Initializes a new instance of the <see cref="StructuralJsonTypeMapping" /> class.
     /// </summary>
     /// <param name="parameters">Parameter object for <see cref="RelationalTypeMapping" />.</param>
-    protected JsonTypeMapping(RelationalTypeMappingParameters parameters)
+    protected StructuralJsonTypeMapping(RelationalTypeMappingParameters parameters)
         : base(parameters)
     {
     }
@@ -45,3 +45,9 @@ protected override string GenerateNonNullSqlLiteral(object value)
         => throw new InvalidOperationException(
             RelationalStrings.MethodNeedsToBeImplementedInTheProvider);
 }
+
+/// <summary>
+///     Use StructuralJsonTypeMapping instead for type mappings representing JSON structural types as opposed to JSON strings.
+/// </summary>
+[Obsolete("Use StructuralJsonTypeMapping instead for type mappings representing JSON structural types as opposed to JSON strings.")]
+public class JsonTypeMapping;

src/EFCore.SqlServer/Query/Internal/SqlServerJsonPostprocessor.cs

@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Diagnostics.CodeAnalysis;
 using Microsoft.EntityFrameworkCore.Query.SqlExpressions;
 using Microsoft.EntityFrameworkCore.SqlServer.Internal;
 using Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal;
@@ -55,8 +54,7 @@ public Expression Process(Expression expression)
     ///     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>
-    [return: NotNullIfNotNull(nameof(expression))]
-    public override Expression? Visit(Expression? expression)
+    protected override Expression VisitExtension(Expression expression)
     {
         switch (expression)
         {
@@ -128,7 +126,7 @@ public Expression Process(Expression expression)
                 {
                     Check.DebugAssert(newTables is null, "newTables must be null if columnsToRewrite is null");
 
-                    result = (SelectExpression)base.Visit(result);
+                    result = (SelectExpression)base.VisitExtension(result);
                 }
                 else
                 {
@@ -154,7 +152,7 @@ public Expression Process(Expression expression)
 
                     // Record the OPENJSON expression and its projected column(s), along with the store type we just removed from the WITH
                     // clause. Then visit the select expression, adding a cast around the matching ColumnExpressions.
-                    result = (SelectExpression)base.Visit(result);
+                    result = (SelectExpression)base.VisitExtension(result);
 
                     foreach (var columnsToRewriteKey in columnsToRewrite.Keys)
                     {
@@ -270,19 +268,30 @@ when _columnsToRewrite.TryGetValue((columnExpression.TableAlias, columnExpressio
                 && left is not SqlConstantExpression { Value: null }
                 && right is not SqlConstantExpression { Value: null }:
             {
-                return comparison.Update(
-                    sqlExpressionFactory.Convert(
-                        left,
-                        typeof(string),
-                        typeMappingSource.FindMapping(typeof(string))),
-                    sqlExpressionFactory.Convert(
-                        right,
-                        typeof(string),
-                        typeMappingSource.FindMapping(typeof(string))));
+                var stringTypeMapping = typeMappingSource.FindMapping(typeof(string))!;
+
+                return comparison.Update(ConvertToString(left), ConvertToString(right));
+
+                SqlExpression ConvertToString(SqlExpression expression)
+                {
+                    if (expression.TypeMapping?.StoreType.Equals("json", StringComparison.OrdinalIgnoreCase) == true)
+                    {
+                        // If the expression happens to be a json literal (CAST('...' AS json)), we can just extract the string inside,
+                        // instead of applying an additional CAST around it
+                        return expression is SqlConstantExpression constant
+                            ? new SqlConstantExpression(
+                                constant.Value,
+                                typeof(string),
+                                (RelationalTypeMapping)stringTypeMapping.WithComposedConverter(constant.TypeMapping!.Converter))
+                            : sqlExpressionFactory.Convert(expression, typeof(string), stringTypeMapping);
+                    }
+
+                    return expression;
+                }
             }
 
             default:
-                return base.Visit(expression);
+                return base.VisitExtension(expression);
         }
 
         static bool IsKeyColumn(SqlExpression sqlExpression, string openJsonTableAlias)

src/EFCore.SqlServer/Query/Internal/SqlServerQueryTranslationPostprocessor.cs

@@ -9,28 +9,19 @@ namespace Microsoft.EntityFrameworkCore.SqlServer.Query.Internal;
 ///     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 class SqlServerQueryTranslationPostprocessor : RelationalQueryTranslationPostprocessor
+public class SqlServerQueryTranslationPostprocessor(
+    QueryTranslationPostprocessorDependencies dependencies,
+    RelationalQueryTranslationPostprocessorDependencies relationalDependencies,
+    SqlServerQueryCompilationContext queryCompilationContext)
+    : RelationalQueryTranslationPostprocessor(dependencies, relationalDependencies, queryCompilationContext)
 {
-    private readonly SqlServerJsonPostprocessor _jsonPostprocessor;
-    private readonly SqlServerAggregateOverSubqueryPostprocessor _aggregatePostprocessor;
-    private readonly SqlServerSqlTreePruner _pruner = new();
+    private readonly SqlServerJsonPostprocessor _jsonPostprocessor = new(
+        relationalDependencies.TypeMappingSource,
+        relationalDependencies.SqlExpressionFactory,
+        queryCompilationContext.SqlAliasManager);
 
-    /// <summary>
-    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
-    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
-    ///     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 SqlServerQueryTranslationPostprocessor(
-        QueryTranslationPostprocessorDependencies dependencies,
-        RelationalQueryTranslationPostprocessorDependencies relationalDependencies,
-        SqlServerQueryCompilationContext queryCompilationContext)
-        : base(dependencies, relationalDependencies, queryCompilationContext)
-    {
-        _jsonPostprocessor = new SqlServerJsonPostprocessor(
-            relationalDependencies.TypeMappingSource, relationalDependencies.SqlExpressionFactory, queryCompilationContext.SqlAliasManager);
-        _aggregatePostprocessor = new SqlServerAggregateOverSubqueryPostprocessor(queryCompilationContext.SqlAliasManager);
-    }
+    private readonly SqlServerAggregateOverSubqueryPostprocessor _aggregatePostprocessor = new(queryCompilationContext.SqlAliasManager);
+    private readonly SqlServerSqlTreePruner _pruner = new();
 
     /// <summary>
     ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to

src/EFCore.SqlServer/Query/Internal/SqlServerQueryableMethodTranslatingExpressionVisitor.cs

@@ -608,6 +608,71 @@ IComplexType complexType
                 false));
     }
 
+    /// <summary>
+    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+    ///     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>
+    protected override ShapedQueryExpression? TranslateContains(ShapedQueryExpression source, Expression item)
+    {
+        // Attempt to translate to JSON_CONTAINS for SQL Server 2025+ (compatibility level 170+).
+        // JSON_CONTAINS is more efficient than IN (SELECT ... FROM OPENJSON(...)) for primitive collections.
+        if (_sqlServerSingletonOptions.SupportsJsonType
+            && source.QueryExpression is SelectExpression
+            {
+                // Primitive collection over OPENJSON (e.g. [p].[Ints])
+                Tables:
+                [
+                    SqlServerOpenJsonExpression
+                    {
+                        // JSON_CONTAINS() is only supported over json, not nvarchar
+                        Json: { TypeMapping: SqlServerJsonTypeMapping } json,
+                        Path: null,
+                        ColumnInfos: [{ Name: "value" }]
+                    }
+                ],
+                Predicate: null,
+                GroupBy: [],
+                Having: null,
+                IsDistinct: false,
+                Limit: null,
+                Offset: null
+            }
+            && TranslateExpression(item, applyDefaultTypeMapping: false) is { } translatedItem
+            // Literal untyped NULL not supported as item by JSON_CONTAINS().
+            // For any other nullable item, SqlServerNullabilityProcessor will add a null check around the JSON_CONTAINS call.
+            && translatedItem is not SqlConstantExpression { Value: null }
+            // Note: JSON_CONTAINS doesn't allow searching for null items within a JSON collection (returns 0)
+            // As a result, we only translate to JSON_CONTAINS when we know that either the item is non-nullable or the collection's elements are.
+            && (
+                translatedItem is ColumnExpression { IsNullable: false } or SqlConstantExpression { Value: not null }
+                || !translatedItem.Type.IsNullableType()
+                || json.Type.GetSequenceType() is var elementClrType && !elementClrType.IsNullableType()))
+        {
+            // JSON_CONTAINS returns 1 if found, 0 if not found. It's a search condition expression.
+            var jsonContains = _sqlExpressionFactory.Equal(
+                _sqlExpressionFactory.Function(
+                    "JSON_CONTAINS",
+                    [json, translatedItem],
+                    nullable: true,
+                    argumentsPropagateNullability: [false, true],
+                    typeof(int)),
+                _sqlExpressionFactory.Constant(1));
+
+#pragma warning disable EF1001 // Internal EF Core API usage.
+            var selectExpression = new SelectExpression(jsonContains, _queryCompilationContext.SqlAliasManager);
+            return source.Update(
+                selectExpression,
+                Expression.Convert(
+                    new ProjectionBindingExpression(selectExpression, new ProjectionMember(), typeof(bool?)),
+                    typeof(bool)));
+#pragma warning restore EF1001 // Internal EF Core API usage.
+        }
+
+        return base.TranslateContains(source, item);
+    }
+
     /// <summary>
     ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
     ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
@@ -623,8 +688,8 @@ IComplexType complexType
         {
             switch (source.QueryExpression)
             {
-                // index on parameter using a column
-                // translate via JSON because it is a better translation
+                // Index on parameter using a column
+                // Translate via JSON_VALUE() instead of via a VALUES subquery
                 case SelectExpression
                 {
                     Tables: [ValuesExpression { ValuesParameter: { } valuesParameter }],
@@ -938,15 +1003,7 @@ protected override bool TrySerializeScalarToJson(
                     // IReadOnlyList<PathSegment> (just like Json{Scalar,Query}Expression), but instead we do the slight hack of packaging it
                     // as a constant argument; it will be unpacked and handled in SQL generation.
                     _sqlExpressionFactory.Constant(path, RelationalTypeMapping.NullMapping),
-
-                    // If an inline JSON object (complex type) is being assigned, it would be rendered here as a simple string:
-                    // [column].modify('$.foo', '{ "x": 8 }')
-                    // Since it's untyped, modify would treat is as a string rather than a JSON object, and insert it as such into
-                    // the enclosing object, escaping all the special JSON characters - that's not what we want.
-                    // We add a cast to JSON to have it interpreted as a JSON object.
-                    value is SqlConstantExpression { TypeMapping.StoreType: "json" }
-                        ? _sqlExpressionFactory.Convert(value, value.Type, _typeMappingSource.FindMapping("json")!)
-                        : value
+                    value
                 ],
                 nullable: true,
                 instancePropagatesNullability: true,

src/EFCore.SqlServer/Query/Internal/SqlServerSqlNullabilityProcessor.cs

@@ -138,6 +138,48 @@ protected virtual SqlExpression VisitSqlServerAggregateFunction(
             : aggregateFunctionExpression;
     }
 
+    /// <summary>
+    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+    ///     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>
+    protected override SqlExpression VisitSqlFunction(
+        SqlFunctionExpression sqlFunctionExpression,
+        bool allowOptimizedExpansion,
+        out bool nullable)
+    {
+        if (sqlFunctionExpression is { Name: "JSON_CONTAINS", Arguments: [var collection, var item] } jsonContains)
+        {
+            // JSON_CONTAINS() does not allow searching for NULL within a JSON collection (always returns zero when the item is NULL).
+            // As a result, we do not translate to JSON_CONTAINS() in SqlServerQueryableMethodTranslatingExpressionVisitor unless we know that
+            // either the item or the collection's elements are non-nullable.
+            // When the item argument is nullable, we add a null check around JSON_CONTAINS():
+            // CASE WHEN @item IS NULL THEN NULL ELSE JSON_CONTAINS(collection, @item) END
+            item = Visit(item, out var itemNullable);
+            collection = Visit(collection, out var collectionNullable);
+
+            sqlFunctionExpression = jsonContains.Update(instance: null, arguments: [collection, item]);
+
+            if (itemNullable && !UseRelationalNulls)
+            {
+                nullable = true;
+                return Dependencies.SqlExpressionFactory.Case(
+                    [
+                        new CaseWhenClause(
+                            Dependencies.SqlExpressionFactory.IsNull(item),
+                            Dependencies.SqlExpressionFactory.Constant(null, typeof(bool?), jsonContains.TypeMapping))
+                    ],
+                    jsonContains);
+            }
+
+            nullable = itemNullable || collectionNullable;
+            return sqlFunctionExpression;
+        }
+
+        return base.VisitSqlFunction(sqlFunctionExpression, allowOptimizedExpansion, out nullable);
+    }
+
     /// <summary>
     ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
     ///     the same compatibility standards as public APIs. It may be changed or removed without notice in

src/EFCore.SqlServer/Query/Internal/SqlServerTypeMappingPostprocessor.cs

@@ -101,14 +101,15 @@ protected virtual SqlServerOpenJsonExpression ApplyTypeMappingsOnOpenJsonExpress
             elementTypeMapping = e;
         }
 
-        if (parameterTypeMapping is not SqlServerStringTypeMapping { ElementTypeMapping: not null })
+        if (parameterTypeMapping is not SqlServerStringTypeMapping { ElementTypeMapping: not null }
+            and not SqlServerJsonTypeMapping { ElementTypeMapping: not null })
         {
-            throw new UnreachableException("A SqlServerStringTypeMapping collection type mapping could not be found");
+            throw new UnreachableException("A string/JSON collection type mapping was not found");
         }
 
         return openJsonExpression.Update(
             parameterExpression.ApplyTypeMapping(parameterTypeMapping),
             path: null,
-            [new SqlServerOpenJsonExpression.ColumnInfo("value", elementTypeMapping, [])]);
+            [new SqlServerOpenJsonExpression.ColumnInfo("value", elementTypeMapping, Path: [])]);
     }
 }