.Net: [MEVD] Support DateTime/DateTimeOffset/DateOnly/TimeOnly across providers

dotnet/src/InternalUtilities/connectors/Memory/MongoDB/BsonValueFactory.cs

@@ -21,10 +21,15 @@ public static BsonValue Create(object? value)
         => value switch
         {
             null => BsonNull.Value,
-            Guid guid => new BsonBinaryData(guid, GuidRepresentation.Standard),
-            object[] array => new BsonArray(Array.ConvertAll(array, Create)),
-            Array array => new BsonArray(array),
-            IEnumerable<object> enumerable => new BsonArray(enumerable.Select(Create)),
+            Guid v => new BsonBinaryData(v, GuidRepresentation.Standard),
+            DateTimeOffset v => new BsonDateTime(v.UtcDateTime),
+#if NET
+            DateOnly v => new BsonDateTime(v.ToDateTime(TimeOnly.MinValue, DateTimeKind.Utc)),
+#endif
+            object[] v => new BsonArray(Array.ConvertAll(v, Create)),
+            Array v => new BsonArray(v),
+            IEnumerable<object> v => new BsonArray(v.Select(Create)),
+
             _ => BsonValue.Create(value)
         };
 }

dotnet/src/InternalUtilities/connectors/Memory/MongoDB/MongoDynamicMapper.cs

@@ -160,14 +160,24 @@ Embedding<float> e
             Type t when t == typeof(int?) => value.AsNullableInt32,
             Type t when t == typeof(long) => value.AsInt64,
             Type t when t == typeof(long?) => value.AsNullableInt64,
-            Type t when t == typeof(float) => ((float)value.AsDouble),
+            Type t when t == typeof(float) => (float)value.AsDouble,
             Type t when t == typeof(float?) => ((float?)value.AsNullableDouble),
             Type t when t == typeof(double) => value.AsDouble,
             Type t when t == typeof(double?) => value.AsNullableDouble,
             Type t when t == typeof(decimal) => value.AsDecimal,
             Type t when t == typeof(decimal?) => value.AsNullableDecimal,
             Type t when t == typeof(DateTime) => value.ToUniversalTime(),
             Type t when t == typeof(DateTime?) => value.ToNullableUniversalTime(),
+            Type t when t == typeof(DateTimeOffset) => new DateTimeOffset(value.ToUniversalTime(), TimeSpan.Zero),
+            Type t when t == typeof(DateTimeOffset?) => value.ToNullableUniversalTime() is DateTime dateTime
+                ? new DateTimeOffset(value.ToUniversalTime(), TimeSpan.Zero)
+                : null,
+#if NET
+            Type t when t == typeof(DateOnly) => DateOnly.FromDateTime(value.ToUniversalTime()),
+            Type t when t == typeof(DateOnly?) => value.ToNullableUniversalTime() is DateTime dateTime
+                ? DateOnly.FromDateTime(dateTime)
+                : null,
+#endif
 
             _ => (object?)null
         };

dotnet/src/InternalUtilities/connectors/Memory/MongoDB/MongoModelBuilder.cs

@@ -58,7 +58,11 @@ protected override void ValidateKeyProperty(KeyPropertyModel keyProperty)
 
     protected override bool IsDataPropertyTypeValid(Type type, [NotNullWhen(false)] out string? supportedTypes)
     {
-        supportedTypes = "string, int, long, double, float, bool, DateTimeOffset, or arrays/lists of these types";
+        supportedTypes = "string, int, long, double, float, bool, decimal, DateTime, DateTimeOffset,"
+#if NET
+            + " DateOnly,"
+#endif
+            + " or arrays/lists of these types";
 
         if (Nullable.GetUnderlyingType(type) is Type underlyingType)
         {
@@ -77,7 +81,12 @@ static bool IsValid(Type type)
                 type == typeof(float) ||
                 type == typeof(double) ||
                 type == typeof(decimal) ||
-                type == typeof(DateTime);
+                type == typeof(DateTime) ||
+                type == typeof(DateTimeOffset) ||
+#if NET
+                type == typeof(DateOnly) ||
+#endif
+                false;
     }
 
     protected override bool IsVectorPropertyTypeValid(Type type, [NotNullWhen(false)] out string? supportedTypes)

dotnet/src/VectorData/AzureAISearch/AzureAISearchCollectionCreateMapping.cs

@@ -128,7 +128,11 @@ public static SearchFieldDataType GetSDKFieldDataType(Type propertyType)
             // Half is also listed by the SDK, but currently not supported.
             Type t when t == typeof(float) => SearchFieldDataType.Double,
             Type t when t == typeof(double) => SearchFieldDataType.Double,
+            Type t when t == typeof(DateTime) => SearchFieldDataType.DateTimeOffset,
             Type t when t == typeof(DateTimeOffset) => SearchFieldDataType.DateTimeOffset,
+#if NET
+            Type t when t == typeof(DateOnly) => SearchFieldDataType.DateTimeOffset,
+#endif
 
             Type t when t == typeof(string[]) => SearchFieldDataType.Collection(SearchFieldDataType.String),
             Type t when t == typeof(List<string>) => SearchFieldDataType.Collection(SearchFieldDataType.String),
@@ -142,8 +146,14 @@ public static SearchFieldDataType GetSDKFieldDataType(Type propertyType)
             Type t when t == typeof(List<float>) => SearchFieldDataType.Collection(SearchFieldDataType.Double),
             Type t when t == typeof(double[]) => SearchFieldDataType.Collection(SearchFieldDataType.Double),
             Type t when t == typeof(List<double>) => SearchFieldDataType.Collection(SearchFieldDataType.Double),
+            Type t when t == typeof(DateTime[]) => SearchFieldDataType.Collection(SearchFieldDataType.DateTimeOffset),
+            Type t when t == typeof(List<DateTime>) => SearchFieldDataType.Collection(SearchFieldDataType.DateTimeOffset),
             Type t when t == typeof(DateTimeOffset[]) => SearchFieldDataType.Collection(SearchFieldDataType.DateTimeOffset),
             Type t when t == typeof(List<DateTimeOffset>) => SearchFieldDataType.Collection(SearchFieldDataType.DateTimeOffset),
+#if NET
+            Type t when t == typeof(DateOnly[]) => SearchFieldDataType.Collection(SearchFieldDataType.DateTimeOffset),
+            Type t when t == typeof(List<DateOnly>) => SearchFieldDataType.Collection(SearchFieldDataType.DateTimeOffset),
+#endif
 
             _ => throw new NotSupportedException($"Data type '{propertyType}' for {nameof(VectorStoreDataProperty)} is not supported by the Azure AI Search VectorStore.")
         };

dotnet/src/VectorData/AzureAISearch/AzureAISearchDynamicMapper.cs

@@ -41,7 +41,7 @@ public JsonObject MapFromDataToStorageModel(Dictionary<string, object?> dataMode
             if (dataModel.TryGetValue(dataProperty.ModelName, out var dataValue))
             {
                 jsonObject[dataProperty.StorageName] = dataValue is not null ?
-                    JsonSerializer.SerializeToNode(dataValue, dataProperty.Type, jsonSerializerOptions) :
+                    JsonSerializer.SerializeToNode(ConvertToStorageValue(dataValue), GetStorageType(dataProperty.Type), jsonSerializerOptions) :
                     null;
             }
         }
@@ -183,6 +183,10 @@ public JsonObject MapFromDataToStorageModel(Dictionary<string, object?> dataMode
             Type t when t == typeof(DateTime?) => value.GetValue<DateTime?>(),
             Type t when t == typeof(DateTimeOffset) => value.GetValue<DateTimeOffset>(),
             Type t when t == typeof(DateTimeOffset?) => value.GetValue<DateTimeOffset?>(),
+#if NET
+            Type t when t == typeof(DateOnly) => DateOnly.FromDateTime(value.GetValue<DateTimeOffset>().DateTime),
+            Type t when t == typeof(DateOnly?) => (DateOnly?)DateOnly.FromDateTime(value.GetValue<DateTimeOffset>().DateTime),
+#endif
 
             _ => (object?)null
         };
@@ -242,4 +246,38 @@ public JsonObject MapFromDataToStorageModel(Dictionary<string, object?> dataMode
 
         throw new UnreachableException($"Unsupported property type '{propertyType.Name}'.");
     }
+
+    /// <summary>
+    /// Converts a value to its storage representation for Azure AI Search.
+    /// Azure AI Search only supports <see cref="DateTimeOffset"/> for date/time types, and always internally
+    /// converts to UTC for storage.
+    /// </summary>
+    /// <summary>
+    /// Gets the storage type for a given property type. Azure AI Search stores DateTime and DateOnly as DateTimeOffset.
+    /// </summary>
+    private static Type GetStorageType(Type propertyType)
+    {
+        var underlying = Nullable.GetUnderlyingType(propertyType) ?? propertyType;
+
+        if (underlying == typeof(DateTime)
+#if NET
+            || underlying == typeof(DateOnly)
+#endif
+        )
+        {
+            return propertyType == underlying ? typeof(DateTimeOffset) : typeof(DateTimeOffset?);
+        }
+
+        return propertyType;
+    }
+
+    private static object ConvertToStorageValue(object value)
+        => value switch
+        {
+            DateTime dateTime => new DateTimeOffset(dateTime, TimeSpan.Zero),
+#if NET
+            DateOnly dateOnly => new DateTimeOffset(dateOnly.ToDateTime(TimeOnly.MinValue), TimeSpan.Zero),
+#endif
+            _ => value
+        };
 }

dotnet/src/VectorData/AzureAISearch/AzureAISearchFilterTranslator.cs

@@ -119,9 +119,17 @@ private void GenerateLiteral(object? value)
                 this._filter.Append('\'').Append(g.ToString()).Append('\'');
                 return;
 
+            case DateTime d:
+                this._filter.Append(new DateTimeOffset(d, TimeSpan.Zero).ToString("o"));
+                return;
             case DateTimeOffset d:
                 this._filter.Append(d.ToString("o"));
                 return;
+#if NET
+            case DateOnly d:
+                this._filter.Append(new DateTimeOffset(d.ToDateTime(TimeOnly.MinValue), TimeSpan.Zero).ToString("o"));
+                return;
+#endif
 
             case Array:
                 throw new NotImplementedException();

dotnet/src/VectorData/AzureAISearch/AzureAISearchMapper.cs

@@ -20,6 +20,29 @@ public JsonObject MapFromDataToStorageModel(TRecord dataModel, int recordIndex,
 
         var jsonObject = JsonSerializer.SerializeToNode(dataModel, jsonSerializerOptions)!.AsObject();
 
+        // Azure AI Search only supports Edm.DateTimeOffset for date/time types.
+        // DateTime properties may be serialized by STJ without timezone info (when Kind=Unspecified),
+        // which Azure AI Search rejects. Convert them to DateTimeOffset (UTC).
+        // DateOnly properties are serialized as "yyyy-MM-dd", which also isn't accepted.
+        // Convert them to full DateTimeOffset representation (midnight UTC).
+        foreach (var dataProperty in model.DataProperties)
+        {
+            var propertyType = Nullable.GetUnderlyingType(dataProperty.Type) ?? dataProperty.Type;
+
+            if (propertyType == typeof(DateTime) && jsonObject.TryGetPropertyValue(dataProperty.StorageName, out var dtNode) && dtNode is not null)
+            {
+                var dateTime = dtNode.Deserialize<DateTime>(jsonSerializerOptions);
+                jsonObject[dataProperty.StorageName] = JsonValue.Create(new DateTimeOffset(DateTime.SpecifyKind(dateTime, DateTimeKind.Utc), TimeSpan.Zero));
+            }
+#if NET
+            else if (propertyType == typeof(DateOnly) && jsonObject.TryGetPropertyValue(dataProperty.StorageName, out var dateNode) && dateNode is not null)
+            {
+                var dateOnly = dateNode.Deserialize<DateOnly>(jsonSerializerOptions);
+                jsonObject[dataProperty.StorageName] = JsonValue.Create(new DateTimeOffset(dateOnly.ToDateTime(TimeOnly.MinValue), TimeSpan.Zero));
+            }
+#endif
+        }
+
         // Go over the vector properties; inject any generated embeddings to overwrite the JSON serialized above.
         // Also, for Embedding<T> properties we also need to overwrite with a simple array (since Embedding<T> gets serialized as a complex object).
         for (var i = 0; i < model.VectorProperties.Count; i++)
@@ -64,6 +87,27 @@ public JsonObject MapFromDataToStorageModel(TRecord dataModel, int recordIndex,
 
     public TRecord MapFromStorageToDataModel(JsonObject storageModel, bool includeVectors)
     {
+        // Azure AI Search stores DateTime properties as Edm.DateTimeOffset.
+        // Convert them back to DateTime so STJ can deserialize them into the correct type.
+        // DateOnly properties also need to be converted back from DateTimeOffset.
+        foreach (var dataProperty in model.DataProperties)
+        {
+            var propertyType = Nullable.GetUnderlyingType(dataProperty.Type) ?? dataProperty.Type;
+
+            if (propertyType == typeof(DateTime) && storageModel.TryGetPropertyValue(dataProperty.StorageName, out var dtNode) && dtNode is not null)
+            {
+                var dateTimeOffset = dtNode.Deserialize<DateTimeOffset>(jsonSerializerOptions);
+                storageModel[dataProperty.StorageName] = JsonValue.Create(dateTimeOffset.UtcDateTime);
+            }
+#if NET
+            else if (propertyType == typeof(DateOnly) && storageModel.TryGetPropertyValue(dataProperty.StorageName, out var dateNode) && dateNode is not null)
+            {
+                var dateTimeOffset = dateNode.Deserialize<DateTimeOffset>(jsonSerializerOptions);
+                storageModel[dataProperty.StorageName] = JsonValue.Create(DateOnly.FromDateTime(dateTimeOffset.DateTime));
+            }
+#endif
+        }
+
         if (includeVectors)
         {
             foreach (var vectorProperty in model.VectorProperties)

dotnet/src/VectorData/AzureAISearch/AzureAISearchModelBuilder.cs

@@ -40,7 +40,11 @@ protected override bool IsVectorPropertyTypeValid(Type type, [NotNullWhen(false)
 
     internal static bool IsDataPropertyTypeValidCore(Type type, [NotNullWhen(false)] out string? supportedTypes)
     {
-        supportedTypes = "string, int, long, double, float, bool, DateTimeOffset, or arrays/lists of these types";
+        supportedTypes = "string, int, long, double, float, bool, DateTime, DateTimeOffset,"
+#if NET
+            + " DateOnly,"
+#endif
+            + " or arrays/lists of these types";
 
         if (Nullable.GetUnderlyingType(type) is Type underlyingType)
         {
@@ -58,6 +62,10 @@ static bool IsValid(Type type)
                type == typeof(double) ||
                type == typeof(float) ||
                type == typeof(bool) ||
+               type == typeof(DateTime) ||
+#if NET
+               type == typeof(DateOnly) ||
+#endif
                type == typeof(DateTimeOffset);
     }
 

dotnet/src/VectorData/CosmosNoSql/CosmosNoSqlFilterTranslator.cs

@@ -136,6 +136,22 @@ private void TranslateConstant(object? value)
                     .Append("Z\"");
                 return;
 
+            case DateTime v:
+                this._sql
+                    .Append('"')
+                    .Append(v.ToString("yyyy-MM-ddTHH:mm:ss.FFFFFF", CultureInfo.InvariantCulture))
+                    .Append('"');
+                return;
+
+#if NET
+            case DateOnly v:
+                this._sql
+                    .Append('"')
+                    .Append(v.ToString("yyyy-MM-dd", CultureInfo.InvariantCulture))
+                    .Append('"');
+                return;
+#endif
+
             case IEnumerable v when v.GetType() is var type && (type.IsArray || type.IsGenericType && type.GetGenericTypeDefinition() == typeof(List<>)):
                 this._sql.Append('[');
 

dotnet/src/VectorData/CosmosNoSql/CosmosNoSqlModelBuilder.cs

@@ -36,7 +36,11 @@ protected override void ValidateKeyProperty(KeyPropertyModel keyProperty)
 
     protected override bool IsDataPropertyTypeValid(Type type, [NotNullWhen(false)] out string? supportedTypes)
     {
-        supportedTypes = "string, int, long, double, float, bool, DateTimeOffset, or arrays/lists of these types";
+        supportedTypes = "string, int, long, double, float, bool, DateTime, DateTimeOffset,"
+#if NET
+            + " DateOnly,"
+#endif
+            + " or arrays/lists of these types";
 
         if (Nullable.GetUnderlyingType(type) is Type underlyingType)
         {
@@ -54,6 +58,10 @@ static bool IsValid(Type type)
                type == typeof(long) ||
                type == typeof(float) ||
                type == typeof(double) ||
+               type == typeof(DateTime) ||
+#if NET
+               type == typeof(DateOnly) ||
+#endif
                type == typeof(DateTimeOffset);
     }
 

dotnet/src/VectorData/MongoDB/MongoFilterTranslator.cs

@@ -69,7 +69,11 @@ private BsonDocument GenerateEqualityComparison(PropertyModel property, object?
             throw new NotSupportedException("MongoDB does not support null checks in vector search pre-filters");
         }
 
-        if (value is DateTime or decimal or IList)
+        if (value is DateTime or DateTimeOffset or decimal or IList
+#if NET
+            or DateOnly
+#endif
+        )
         {
             // Operand type is not supported for $vectorSearch: date/decimal
             throw new NotSupportedException($"MongoDB does not support type {value.GetType().Name} in vector search pre-filters.");

dotnet/src/VectorData/PgVector/PostgresFilterTranslator.cs

@@ -55,6 +55,16 @@ protected override void TranslateConstant(object? value, bool isSearchCondition)
                 this._sql.Append('\'').Append(dateTimeOffset.ToString("yyyy-MM-ddTHH:mm:ss.FFFFFFZ", CultureInfo.InvariantCulture)).Append('\'');
                 return;
 
+#if NET
+            case DateOnly dateOnly:
+                this._sql.Append('\'').Append(dateOnly.ToString("yyyy-MM-dd", CultureInfo.InvariantCulture)).Append('\'');
+                return;
+
+            case TimeOnly timeOnly:
+                this._sql.Append('\'').Append(timeOnly.ToString("HH:mm:ss.FFFFFFF", CultureInfo.InvariantCulture)).Append('\'');
+                return;
+#endif
+
             // Array constants (ARRAY[1, 2, 3])
             case IEnumerable v when v.GetType() is var type && (type.IsArray || type.IsGenericType && type.GetGenericTypeDefinition() == typeof(List<>)):
                 this._sql.Append("ARRAY[");

dotnet/src/VectorData/PgVector/PostgresMapper.cs

@@ -156,6 +156,14 @@ private static void PopulateProperty(PropertyModel property, NpgsqlDataReader re
                     case var t when t == typeof(DateTimeOffset):
                         property.SetValue(record, reader.GetFieldValue<DateTimeOffset>(ordinal));
                         return;
+#if NET
+                    case var t when t == typeof(DateOnly):
+                        property.SetValue(record, reader.GetFieldValue<DateOnly>(ordinal));
+                        return;
+                    case var t when t == typeof(TimeOnly):
+                        property.SetValue(record, reader.GetFieldValue<TimeOnly>(ordinal));
+                        return;
+#endif
                     case var t when t == typeof(byte[]):
                         property.SetValue(record, reader.GetFieldValue<byte[]>(ordinal));
                         return;
@@ -203,6 +211,14 @@ private static void PopulateProperty(PropertyModel property, NpgsqlDataReader re
                             case Type t when t == typeof(List<DateTimeOffset>):
                                 property.SetValueAsObject(record, reader.GetFieldValue<List<DateTimeOffset>>(ordinal));
                                 return;
+#if NET
+                            case Type t when t == typeof(List<DateOnly>):
+                                property.SetValueAsObject(record, reader.GetFieldValue<List<DateOnly>>(ordinal));
+                                return;
+                            case Type t when t == typeof(List<TimeOnly>):
+                                property.SetValueAsObject(record, reader.GetFieldValue<List<TimeOnly>>(ordinal));
+                                return;
+#endif
                             case Type t when t == typeof(List<byte[]>):
                                 property.SetValueAsObject(record, reader.GetFieldValue<List<byte[]>>(ordinal));
                                 return;

dotnet/src/VectorData/PgVector/PostgresModelBuilder.cs

@@ -65,6 +65,10 @@ static bool IsValid(Type type)
                 type == typeof(byte[]) ||
                 type == typeof(DateTime) ||
                 type == typeof(DateTimeOffset) ||
+#if NET
+                type == typeof(DateOnly) ||
+                type == typeof(TimeOnly) ||
+#endif
                 type == typeof(Guid);
     }
 

dotnet/src/VectorData/PgVector/PostgresPropertyMapping.cs

@@ -61,6 +61,11 @@ internal static class PostgresPropertyMapping
             Type t when t == typeof(DateTime) && property.IsTimestampWithoutTimezone() => NpgsqlDbType.Timestamp,
             Type t when t == typeof(DateTime) => NpgsqlDbType.TimestampTz,
 
+#if NET
+            Type t when t == typeof(DateOnly) => NpgsqlDbType.Date,
+            Type t when t == typeof(TimeOnly) => NpgsqlDbType.Time,
+#endif
+
             _ => null
         };
 
@@ -84,6 +89,10 @@ static bool TryGetBaseType(Type type, [NotNullWhen(true)] out string? typeName)
                 Type t when t == typeof(byte[]) => "BYTEA",
                 Type t when t == typeof(DateTime) => "TIMESTAMPTZ",
                 Type t when t == typeof(DateTimeOffset) => "TIMESTAMPTZ",
+#if NET
+                Type t when t == typeof(DateOnly) => "DATE",
+                Type t when t == typeof(TimeOnly) => "TIME",
+#endif
                 Type t when t == typeof(Guid) => "UUID",
                 _ => null
             };