Allow configuring the column type with ToJson()

src/EFCore.Relational/Extensions/RelationalComplexCollectionBuilderExtensions.cs

@@ -71,4 +71,31 @@ public static ComplexCollectionBuilder<TComplex> HasJsonPropertyName<TComplex>(
         string? name)
         where TComplex : notnull
         => (ComplexCollectionBuilder<TComplex>)HasJsonPropertyName((ComplexCollectionBuilder)complexCollectionBuilder, name);
+
+    /// <summary>
+    ///     Configures the column type for the JSON column that stores the complex collection.
+    /// </summary>
+    /// <param name="complexCollectionBuilder">The builder for the complex collection being configured.</param>
+    /// <param name="columnType">The database type for the column, or <see langword="null" /> to use the database default.</param>
+    /// <returns>The same builder instance so that multiple calls can be chained.</returns>
+    public static ComplexCollectionBuilder HasColumnType(
+        this ComplexCollectionBuilder complexCollectionBuilder,
+        string? columnType)
+    {
+        complexCollectionBuilder.Metadata.ComplexType.SetContainerColumnType(columnType);
+
+        return complexCollectionBuilder;
+    }
+
+    /// <summary>
+    ///     Configures the column type for the JSON column that stores the complex collection.
+    /// </summary>
+    /// <param name="complexCollectionBuilder">The builder for the complex collection being configured.</param>
+    /// <param name="columnType">The database type for the column, or <see langword="null" /> to use the database default.</param>
+    /// <returns>The same builder instance so that multiple calls can be chained.</returns>
+    public static ComplexCollectionBuilder<TComplex> HasColumnType<TComplex>(
+        this ComplexCollectionBuilder<TComplex> complexCollectionBuilder,
+        string? columnType)
+        where TComplex : notnull
+        => (ComplexCollectionBuilder<TComplex>)HasColumnType((ComplexCollectionBuilder)complexCollectionBuilder, columnType);
 }

src/EFCore.Relational/Extensions/RelationalComplexPropertyBuilderExtensions.cs

@@ -72,4 +72,31 @@ public static ComplexPropertyBuilder<TComplex> HasJsonPropertyName<TComplex>(
         string? name)
         where TComplex : notnull
         => (ComplexPropertyBuilder<TComplex>)HasJsonPropertyName((ComplexPropertyBuilder)complexPropertyBuilder, name);
+
+    /// <summary>
+    ///     Configures the column type for the JSON column that stores the complex property.
+    /// </summary>
+    /// <param name="complexPropertyBuilder">The builder for the complex property being configured.</param>
+    /// <param name="columnType">The database type for the column, or <see langword="null" /> to use the database default.</param>
+    /// <returns>The same builder instance so that multiple calls can be chained.</returns>
+    public static ComplexPropertyBuilder HasColumnType(
+        this ComplexPropertyBuilder complexPropertyBuilder,
+        string? columnType)
+    {
+        complexPropertyBuilder.Metadata.ComplexType.SetContainerColumnType(columnType);
+
+        return complexPropertyBuilder;
+    }
+
+    /// <summary>
+    ///     Configures the column type for the JSON column that stores the complex property.
+    /// </summary>
+    /// <param name="complexPropertyBuilder">The builder for the complex property being configured.</param>
+    /// <param name="columnType">The database type for the column, or <see langword="null" /> to use the database default.</param>
+    /// <returns>The same builder instance so that multiple calls can be chained.</returns>
+    public static ComplexPropertyBuilder<TComplex> HasColumnType<TComplex>(
+        this ComplexPropertyBuilder<TComplex> complexPropertyBuilder,
+        string? columnType)
+        where TComplex : notnull
+        => (ComplexPropertyBuilder<TComplex>)HasColumnType((ComplexPropertyBuilder)complexPropertyBuilder, columnType);
 }

src/EFCore.Relational/Extensions/RelationalEntityTypeExtensions.cs

@@ -1564,87 +1564,6 @@ public static void SetMappingStrategy(this IMutableEntityType entityType, string
     public static bool IsMappedToJson(this IReadOnlyEntityType entityType)
         => !string.IsNullOrEmpty(entityType.GetContainerColumnName());
 
-    /// <summary>
-    ///     Sets the name of the container column to which the entity type is mapped.
-    /// </summary>
-    /// <param name="entityType">The entity type to set the container column name for.</param>
-    /// <param name="columnName">The name to set.</param>
-    public static void SetContainerColumnName(this IMutableEntityType entityType, string? columnName)
-        => entityType.SetOrRemoveAnnotation(RelationalAnnotationNames.ContainerColumnName, columnName);
-
-    /// <summary>
-    ///     Sets the name of the container column to which the entity type is mapped.
-    /// </summary>
-    /// <param name="entityType">The entity type to set the container column name for.</param>
-    /// <param name="columnName">The name to set.</param>
-    /// <param name="fromDataAnnotation">Indicates whether the configuration was specified using a data annotation.</param>
-    /// <returns>The configured value.</returns>
-    public static string? SetContainerColumnName(
-        this IConventionEntityType entityType,
-        string? columnName,
-        bool fromDataAnnotation = false)
-        => (string?)entityType.SetAnnotation(RelationalAnnotationNames.ContainerColumnName, columnName, fromDataAnnotation)?.Value;
-
-    /// <summary>
-    ///     Gets the <see cref="ConfigurationSource" /> for the container column name.
-    /// </summary>
-    /// <param name="entityType">The entity type to set the container column name for.</param>
-    /// <returns>The <see cref="ConfigurationSource" /> for the container column name.</returns>
-    public static ConfigurationSource? GetContainerColumnNameConfigurationSource(this IConventionEntityType entityType)
-        => entityType.FindAnnotation(RelationalAnnotationNames.ContainerColumnName)
-            ?.GetConfigurationSource();
-
-    /// <summary>
-    ///     Gets the container column name to which the entity type is mapped.
-    /// </summary>
-    /// <param name="entityType">The entity type to get the container column name for.</param>
-    /// <returns>The container column name to which the entity type is mapped.</returns>
-    public static string? GetContainerColumnName(this IReadOnlyEntityType entityType)
-    {
-        var containerColumnName = entityType.FindAnnotation(RelationalAnnotationNames.ContainerColumnName);
-        return containerColumnName == null
-                ? entityType.FindOwnership()?.PrincipalEntityType.GetContainerColumnName()
-                : (string?)containerColumnName.Value;
-    }
-
-    /// <summary>
-    ///     Sets the column type to use for the container column to which the entity type is mapped.
-    /// </summary>
-    /// <param name="entityType">The entity type.</param>
-    /// <param name="columnType">The database column type.</param>
-    public static void SetContainerColumnType(this IMutableEntityType entityType, string? columnType)
-        => entityType.SetOrRemoveAnnotation(RelationalAnnotationNames.ContainerColumnType, columnType);
-
-    /// <summary>
-    ///     Sets the column type to use for the container column to which the entity type is mapped.
-    /// </summary>
-    /// <param name="entityType">The entity type.</param>
-    /// <param name="columnType">The database column type.</param>
-    /// <param name="fromDataAnnotation">Indicates whether the configuration was specified using a data annotation.</param>
-    /// <returns>The configured value.</returns>
-    public static string? SetContainerColumnType(
-        this IConventionEntityType entityType,
-        string? columnType,
-        bool fromDataAnnotation = false)
-        => (string?)entityType.SetAnnotation(RelationalAnnotationNames.ContainerColumnType, columnType, fromDataAnnotation)?.Value;
-
-    /// <summary>
-    ///     Gets the <see cref="ConfigurationSource" /> for the container column type.
-    /// </summary>
-    /// <param name="entityType">The entity type.</param>
-    /// <returns>The <see cref="ConfigurationSource" />.</returns>
-    public static ConfigurationSource? GetContainerColumnTypeConfigurationSource(this IConventionEntityType entityType)
-        => entityType.FindAnnotation(RelationalAnnotationNames.ContainerColumnType)
-            ?.GetConfigurationSource();
-
-    /// <summary>
-    ///     Gets the column type to use for the container column to which the entity type is mapped.
-    /// </summary>
-    /// <param name="entityType">The entity type.</param>
-    /// <returns>The database column type.</returns>
-    public static string? GetContainerColumnType(this IReadOnlyEntityType entityType)
-        => entityType.FindAnnotation(RelationalAnnotationNames.ContainerColumnType)?.Value as string;
-
     /// <summary>
     ///     Sets the type mapping for the container column to which the entity type is mapped.
     /// </summary>

src/EFCore.Relational/Extensions/RelationalPropertyExtensions.cs

@@ -2047,11 +2047,14 @@ private static TValue ThrowReadValueException<TValue>(
     /// <param name="property">The property.</param>
     /// <returns>
     ///     The value for the JSON property used to store the value of this entity property.
-    ///     <see langword="null" /> is returned for key properties and for properties of entities that are not mapped to a JSON column.
+    ///     By default <see langword="null" /> is returned for key properties and for properties that
+    ///     are not mapped to JSON.
     /// </returns>
     public static string? GetJsonPropertyName(this IReadOnlyProperty property)
         => (string?)property.FindAnnotation(RelationalAnnotationNames.JsonPropertyName)?.Value
-            ?? (property.IsKey() || !property.DeclaringType.IsMappedToJson() ? null : property.Name);
+            ?? (property.IsKey() || !property.DeclaringType.IsMappedToJson()
+                ? null
+                : property == property.DeclaringType.FindDiscriminatorProperty() ? "$type" : property.Name);
 
     /// <summary>
     ///     Sets the value of JSON property name used for the given property of an entity mapped to a JSON column.

src/EFCore.Relational/Extensions/RelationalTypeBaseExtensions.cs

@@ -4,6 +4,7 @@
 // ReSharper disable once CheckNamespace
 
 using Microsoft.EntityFrameworkCore.Internal;
+using Microsoft.EntityFrameworkCore.Metadata.Internal;
 
 namespace Microsoft.EntityFrameworkCore;
 
@@ -370,20 +371,87 @@ public static bool IsMappedToJson(this IReadOnlyTypeBase typeBase)
     /// <param name="typeBase">The type to get the container column name for.</param>
     /// <returns>The container column name to which the type is mapped.</returns>
     public static string? GetContainerColumnName(this IReadOnlyTypeBase typeBase)
-        => typeBase is IReadOnlyEntityType entityType
-            ? entityType.GetContainerColumnName()
-            : ((IReadOnlyComplexType)typeBase).GetContainerColumnName();
+    {
+        var containerColumnName = typeBase.FindAnnotation(RelationalAnnotationNames.ContainerColumnName);
+        return containerColumnName != null
+                ? (string?)containerColumnName.Value
+                : typeBase is IReadOnlyEntityType entityType
+                    ? entityType.FindOwnership()?.PrincipalEntityType.GetContainerColumnName()
+                    : ((IReadOnlyComplexType)typeBase).ComplexProperty.DeclaringType.GetContainerColumnName();
+    }
+
+    /// <summary>
+    ///     Sets the name of the container column to which the type is mapped.
+    /// </summary>
+    /// <param name="typeBase">The type to set the container column name for.</param>
+    /// <param name="columnName">The name to set.</param>
+    public static void SetContainerColumnName(this IMutableTypeBase typeBase, string? columnName)
+        => typeBase.SetOrRemoveAnnotation(RelationalAnnotationNames.ContainerColumnName, columnName);
+
+    /// <summary>
+    ///     Sets the name of the container column to which the type is mapped.
+    /// </summary>
+    /// <param name="typeBase">The type to set the container column name for.</param>
+    /// <param name="columnName">The name to set.</param>
+    /// <param name="fromDataAnnotation">Indicates whether the configuration was specified using a data annotation.</param>
+    /// <returns>The configured value.</returns>
+    public static string? SetContainerColumnName(
+        this IConventionTypeBase typeBase,
+        string? columnName,
+        bool fromDataAnnotation = false)
+        => (string?)typeBase.SetAnnotation(RelationalAnnotationNames.ContainerColumnName, columnName, fromDataAnnotation)?.Value;
+
+    /// <summary>
+    ///     Gets the <see cref="ConfigurationSource" /> for the container column name.
+    /// </summary>
+    /// <param name="typeBase">The type to get the container column name configuration source for.</param>
+    /// <returns>The <see cref="ConfigurationSource" /> for the container column name.</returns>
+    public static ConfigurationSource? GetContainerColumnNameConfigurationSource(this IConventionTypeBase typeBase)
+        => typeBase.FindAnnotation(RelationalAnnotationNames.ContainerColumnName)
+            ?.GetConfigurationSource();
 
     /// <summary>
     ///     Gets the column type to use for the container column to which the type is mapped.
     /// </summary>
     /// <param name="typeBase">The type.</param>
     /// <returns>The database column type.</returns>
     public static string? GetContainerColumnType(this IReadOnlyTypeBase typeBase)
-        => typeBase is IReadOnlyEntityType entityType
-            ? entityType.GetContainerColumnType()
-            : null;
+     => typeBase.FindAnnotation(RelationalAnnotationNames.ContainerColumnType)?.Value is string columnName
+            ? columnName
+            : typeBase is IReadOnlyEntityType entityType
+                ? entityType.FindOwnership()?.PrincipalEntityType.GetContainerColumnType()
+                : ((IReadOnlyComplexType)typeBase).ComplexProperty.DeclaringType.GetContainerColumnType();
+
+    /// <summary>
+    ///     Sets the type of the container column to which the type is mapped.
+    /// </summary>
+    /// <param name="typeBase">The type to set the container column type for.</param>
+    /// <param name="columnType">The type to set.</param>
+    public static void SetContainerColumnType(this IMutableTypeBase typeBase, string? columnType)
+        => typeBase.SetOrRemoveAnnotation(RelationalAnnotationNames.ContainerColumnType, columnType);
 
+    /// <summary>
+    ///     Sets the type of the container column to which the type is mapped.
+    /// </summary>
+    /// <param name="typeBase">The type to set the container column type for.</param>
+    /// <param name="columnType">The type to set.</param>
+    /// <param name="fromDataAnnotation">Indicates whether the configuration was specified using a data annotation.</param>
+    /// <returns>The configured value.</returns>
+    public static string? SetContainerColumnType(
+        this IConventionTypeBase typeBase,
+        string? columnType,
+        bool fromDataAnnotation = false)
+        => (string?)typeBase.SetAnnotation(RelationalAnnotationNames.ContainerColumnType, columnType, fromDataAnnotation)?.Value;
+
+    /// <summary>
+    ///     Gets the <see cref="ConfigurationSource" /> for the container column type.
+    /// </summary>
+    /// <param name="typeBase">The type to get the container column type configuration source for.</param>
+    /// <returns>The <see cref="ConfigurationSource" /> for the container column type.</returns>
+    public static ConfigurationSource? GetContainerColumnTypeConfigurationSource(this IConventionTypeBase typeBase)
+        => typeBase.FindAnnotation(RelationalAnnotationNames.ContainerColumnType)
+            ?.GetConfigurationSource();
+
     /// <summary>
     ///     Gets the value of JSON property name used for the given entity mapped to a JSON column.
     /// </summary>