MilvusVectorStore: Add support for nested MetadataFilters and FilterO…

…perator.IS_EMPTY (run-llama#16329)

llama-index-integrations/vector_stores/llama-index-vector-stores-milvus/llama_index/vector_stores/milvus/utils.py

@@ -106,8 +106,11 @@ def parse_standard_filters(standard_filters: MetadataFilters = None):
         return filters, ""
 
     for filter in standard_filters.filters:
+        if isinstance(filter, MetadataFilters):
+            filters.append(f"({parse_standard_filters(filter)[1]})")
+            continue
         filter_value = parse_filter_value(filter.value)
-        if filter_value is None:
+        if filter_value is None and filter.operator != FilterOperator.IS_EMPTY:
             continue
 
         if filter.operator == FilterOperator.NIN:
@@ -122,6 +125,9 @@ def parse_standard_filters(standard_filters: MetadataFilters = None):
             filters.append(
                 f"{filter.key!s} like {parse_filter_value(filter.value, True)}"
             )
+        elif filter.operator == FilterOperator.IS_EMPTY:
+            # in Milvus, array_length(field_name) returns 0 if the field does not exist or is not an array
+            filters.append(f"array_length({filter.key!s}) == 0")
         elif filter.operator in [
             FilterOperator.EQ,
             FilterOperator.GT,

llama-index-integrations/vector_stores/llama-index-vector-stores-milvus/pyproject.toml

@@ -27,7 +27,7 @@ exclude = ["**/BUILD"]
 license = "MIT"
 name = "llama-index-vector-stores-milvus"
 readme = "README.md"
-version = "0.2.6"
+version = "0.2.7"
 
 [tool.poetry.dependencies]
 python = ">=3.8.1,<4.0"

llama-index-integrations/vector_stores/llama-index-vector-stores-milvus/tests/test_vector_stores_milvus.py

@@ -128,6 +128,12 @@ def test_to_milvus_filter_with_various_operators():
     expr = _to_milvus_filter(filters)
     assert expr == "array_contains_all(a, [1, 2])"
 
+    filters = MetadataFilters(
+        filters=[MetadataFilter(key="a", value=None, operator=FilterOperator.IS_EMPTY)]
+    )
+    expr = _to_milvus_filter(filters)
+    assert expr == "array_length(a) == 0"
+
 
 def test_to_milvus_filter_with_string_value():
     filters = MetadataFilters(filters=[MetadataFilter(key="a", value="hello")])
@@ -181,6 +187,24 @@ def test_to_milvus_filter_with_multiple_filters():
     assert expr == "(a < 1 or a > 10)"
 
 
+def test_milvus_filter_with_nested_filters():
+    filters = MetadataFilters(
+        filters=[
+            MetadataFilter(key="a", value=1, operator=FilterOperator.EQ),
+            MetadataFilters(
+                filters=[
+                    MetadataFilter(key="b", value=2, operator=FilterOperator.EQ),
+                    MetadataFilter(key="c", value=3, operator=FilterOperator.EQ),
+                ],
+                condition=FilterCondition.OR,
+            ),
+        ],
+        condition=FilterCondition.AND,
+    )
+    expr = _to_milvus_filter(filters)
+    assert expr == "(a == 1 and (b == 2 or c == 3))"
+
+
 def test_milvus_vector_store():
     vector_store = MilvusVectorStore(
         dim=1536,