Add details about querying custom persistable property

source/includes/api-details/csharp/crud/read-query-mixed-properties-description.rst

@@ -0,0 +1,7 @@
+You can query a :dotnet-sdk:`RealmValue <reference/Realms.RealmValue.html>`
+field just like any other data type. Operators that only work with certain
+types, such as string operators and arithmetic operators, ignore
+values that do not contain that type. Negating such operators matches
+values that do not contain the type. Type queries match the underlying
+type, rather than ``RealmValue``. Arithmetic operators convert numeric
+values implicitly to compare across types.

source/includes/api-details/dart/crud/read-query-mixed-properties-description.rst

@@ -0,0 +1,7 @@
+You can query a :flutter-sdk:`RealmValue <realm/RealmValue-class.html>`
+field just like any other data type. Operators that only work with certain
+types, such as string operators and arithmetic operators, ignore
+values that do not contain that type. Negating such operators matches
+values that do not contain the type. Type queries match the underlying
+type, rather than ``RealmValue``. Arithmetic operators convert numeric
+values implicitly to compare across types.

source/includes/api-details/generic/crud/read-query-custom-persistable-property-not-supported.rst

@@ -0,0 +1 @@
+The selected language does not currently support type projection.

source/includes/api-details/objectivec/crud/read-query-custom-persistable-property-description.rst

@@ -0,0 +1,36 @@
+Queries on SDK Objects
+``````````````````````
+
+When working with projected types, queries operate on the persisted type. 
+However, you can use the mapped types interchangeably with the persisted 
+types in arguments in most cases. The exception is queries on embedded 
+objects.
+
+.. tip::
+
+   Projected types support :ref:`sorting and aggregates <sdks-filter-data-swift>`
+   where the persisted type supports them.
+
+Queries on Embedded Objects
+```````````````````````````
+
+You can query embedded types on the supported property types within the 
+object using memberwise equality. 
+
+Object link properties support equality comparisons, but do not support 
+memberwise comparisons. You can query embedded objects for memberwise
+equality on all primitive types. You cannot perform memberwise comparison 
+on objects and collections.
+
+Dynamic APIs
+````````````
+
+Because the schema has no concept of custom type mappings, reading data via
+any of the dynamic APIs gives the underlying persisted type. The SDK does 
+support writing mapped types via a dynamic API, and converts the projected
+type to the persisted type.
+
+The most common use of the dynamic APIs is migration. You can write projected
+types during migration, and the SDK converts the projected type to the persisted
+type. However, reading data during a migration gives the underlying persisted
+type.

source/includes/api-details/swift/crud/read-query-custom-persistable-property-description.rst

@@ -0,0 +1,39 @@
+Queries on SDK Objects
+``````````````````````
+
+When working with projected types, queries operate on the persisted type. 
+However, you can use the mapped types interchangeably with the persisted 
+types in arguments in most cases. The exception is queries on embedded 
+objects.
+
+.. tip::
+
+   Projected types support :ref:`sorting and aggregates <sdks-filter-data-swift>`
+   where the persisted type supports them.
+
+.. literalinclude:: /examples/generated/code/start/TypeProjection.snippet.query-objects-with-type-projection.swift
+   :language: swift
+
+Queries on Embedded Objects
+```````````````````````````
+
+You can query embedded types on the supported property types within the 
+object using memberwise equality. 
+
+Object link properties support equality comparisons, but do not support 
+memberwise comparisons. You can query embedded objects for memberwise
+equality on all primitive types. You cannot perform memberwise comparison 
+on objects and collections.
+
+Dynamic APIs
+````````````
+
+Because the schema has no concept of custom type mappings, reading data via
+any of the dynamic APIs gives the underlying persisted type. The SDK does 
+support writing mapped types via a dynamic API, and converts the projected
+type to the persisted type.
+
+The most common use of the dynamic APIs is migration. You can write projected
+types during migration, and the SDK converts the projected type to the persisted
+type. However, reading data during a migration gives the underlying persisted
+type.

source/sdk/crud/read.txt

@@ -1463,12 +1463,12 @@ a mixed property the same way you would any property.
    .. tab::
       :tabid: csharp
 
-
+      .. include:: /includes/api-details/csharp/crud/read-query-mixed-properties-description.rst
 
    .. tab::
       :tabid: dart
 
-
+      .. include:: /includes/api-details/dart/crud/read-query-mixed-properties-description.rst
 
    .. tab::
       :tabid: java
@@ -1530,6 +1530,62 @@ For details about supported operators and list comparisons, refer to the
 Query a Custom Persistable Property
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
+When you use :ref:`type projection <sdks-type-projection>` to map unsupported 
+types to supported types, accessing those properties is often based on the 
+persisted type.
+
+.. tabs-drivers::
+
+   .. tab::
+      :tabid: cpp-sdk
+
+      .. include:: /includes/api-details/generic/crud/read-custom-persistable-property-not-supported.rst
+
+   .. tab::
+      :tabid: csharp
+
+      .. include:: /includes/api-details/generic/crud/read-custom-persistable-property-not-supported.rst
+
+   .. tab::
+      :tabid: dart
+
+      .. include:: /includes/api-details/generic/crud/read-custom-persistable-property-not-supported.rst
+
+   .. tab::
+      :tabid: java
+
+      .. include:: /includes/api-details/generic/crud/read-query-custom-persistable-property-not-supported.rst
+
+   .. tab::
+      :tabid: java-kotlin
+
+      .. include:: /includes/api-details/generic/crud/read-query-custom-persistable-property-not-supported.rst
+
+   .. tab::
+      :tabid: javascript
+
+      .. include:: /includes/api-details/generic/crud/read-query-custom-persistable-property-not-supported.rst
+
+   .. tab::
+      :tabid: kotlin
+
+      .. include:: /includes/api-details/generic/crud/read-query-custom-persistable-property-not-supported.rst
+
+   .. tab::
+      :tabid: objectivec
+
+      .. include:: /includes/api-details/objectivec/crud/read-query-custom-persistable-property-description.rst
+
+   .. tab::
+      :tabid: swift
+
+      .. include:: /includes/api-details/swift/crud/read-query-custom-persistable-property-description.rst
+
+   .. tab::
+      :tabid: typescript
+
+      .. include:: /includes/api-details/generic/crud/read-query-custom-persistable-property-not-supported.rst
+
 .. _sdks-read-filter-property-behaviors:
 
 Filter by Property Behaviors

source/sdk/model-data/property-types.txt

@@ -95,3 +95,8 @@ Other Property Types
 
 Define an Enum Property
 ~~~~~~~~~~~~~~~~~~~~~~~
+
+.. _sdks-type-projection:
+
+Map Unsupported Types to Supported Types
+----------------------------------------