Add support for Structured ARRAY

README.md

@@ -367,6 +367,79 @@ data_object  = json.loads(row[1])
 data_array   = json.loads(row[2])
 ```
 
+### Structured Data Types Support
+
+This module defines custom SQLAlchemy types for Snowflake structured data, specifically for **Iceberg tables**.
+The types —**MAP**, **OBJECT**, and **ARRAY**— allow you to store complex data structures in your SQLAlchemy models.
+For detailed information, refer to the Snowflake [Structured data types](https://docs.snowflake.com/en/sql-reference/data-types-structured) documentation.
+
+---
+
+#### MAP
+
+The `MAP` type represents a collection of key-value pairs, where each key and value can have different types.
+
+- **Key Type**: The type of the keys (e.g., `TEXT`, `NUMBER`).
+- **Value Type**: The type of the values (e.g., `TEXT`, `NUMBER`).
+- **Not Null**: Whether `NULL` values are allowed (default is `False`).
+
+*Example Usage*
+
+```python
+IcebergTable(
+    table_name,
+    metadata,
+    Column("id", Integer, primary_key=True),
+    Column("map_col", MAP(NUMBER(10, 0), TEXT(16777216))),
+    external_volume="external_volume",
+    base_location="base_location",
+)
+```
+
+#### OBJECT
+
+The `OBJECT` type represents a semi-structured object with named fields. Each field can have a specific type, and you can also specify whether each field is nullable.
+
+- **Items Types**: A dictionary of field names and their types. The type can optionally include a nullable flag (`True` for not nullable, `False` for nullable, default is `False`).
+
+*Example Usage*
+
+```python
+IcebergTable(
+    table_name,
+    metadata,
+    Column("id", Integer, primary_key=True),
+    Column(
+        "object_col",
+        OBJECT(key1=(TEXT(16777216), False), key2=(NUMBER(10, 0), False)),
+        OBJECT(key1=TEXT(16777216), key2=NUMBER(10, 0)), # Without nullable flag
+    ),
+    external_volume="external_volume",
+    base_location="base_location",
+)
+```
+
+#### ARRAY
+
+The `ARRAY` type represents an ordered list of values, where each element has the same type. The type of the elements is defined when creating the array.
+
+- **Value Type**: The type of the elements in the array (e.g., `TEXT`, `NUMBER`).
+- **Not Null**: Whether `NULL` values are allowed (default is `False`).
+
+*Example Usage*
+
+```python
+IcebergTable(
+    table_name,
+    metadata,
+    Column("id", Integer, primary_key=True),
+    Column("array_col", ARRAY(TEXT(16777216))),
+    external_volume="external_volume",
+    base_location="base_location",
+)
+```
+
+
 ### CLUSTER BY Support
 
 Snowflake SQLAchemy supports the `CLUSTER BY` parameter for tables. For information about the parameter, see :doc:`/sql-reference/sql/create-table`.

src/snowflake/sqlalchemy/base.py

@@ -1096,7 +1096,10 @@ def visit_MAP(self, type_, **kw):
         )
 
     def visit_ARRAY(self, type_, **kw):
-        return "ARRAY"
+        if type_.is_semi_structured:
+            return "ARRAY"
+        not_null = f" {NOT_NULL}" if type_.not_null else ""
+        return f"ARRAY({type_.value_type.compile()}{not_null})"
 
     def visit_OBJECT(self, type_, **kw):
         if type_.is_semi_structured:

src/snowflake/sqlalchemy/custom_types.py

@@ -1,7 +1,7 @@
 #
 # Copyright (c) 2012-2023 Snowflake Computing Inc. All rights reserved.
 #
-from typing import Tuple, Union
+from typing import Optional, Tuple, Union
 
 import sqlalchemy.types as sqltypes
 import sqlalchemy.util as util
@@ -40,7 +40,8 @@ class VARIANT(SnowflakeType):
 
 
 class StructuredType(SnowflakeType):
-    def __init__(self):
+    def __init__(self, is_semi_structured: bool = False):
+        self.is_semi_structured = is_semi_structured
         super().__init__()
 
 
@@ -81,9 +82,18 @@ def __repr__(self):
         )
 
 
-class ARRAY(SnowflakeType):
+class ARRAY(StructuredType):
     __visit_name__ = "ARRAY"
 
+    def __init__(
+        self,
+        value_type: Optional[sqltypes.TypeEngine] = None,
+        not_null: bool = False,
+    ):
+        self.value_type = value_type
+        self.not_null = not_null
+        super().__init__(is_semi_structured=value_type is None)
+
 
 class TIMESTAMP_TZ(SnowflakeType):
     __visit_name__ = "TIMESTAMP_TZ"

src/snowflake/sqlalchemy/parser/custom_type_parser.py

@@ -74,6 +74,8 @@
     "GEOMETRY": GEOMETRY,
 }
 
+NOT_NULL_STR = "NOT NULL"
+
 
 def tokenize_parameters(text: str, character_for_strip=",") -> list:
     """
@@ -160,6 +162,8 @@ def parse_type(type_text: str) -> TypeEngine:
             col_type_kw = __parse_map_type_parameters(parameters)
         elif issubclass(col_type_class, OBJECT):
             col_type_kw = __parse_object_type_parameters(parameters)
+        elif issubclass(col_type_class, ARRAY):
+            col_type_kw = __parse_nullable_parameter(parameters)
         if col_type_kw is None:
             col_type_class = NullType
             col_type_kw = {}
@@ -169,6 +173,7 @@ def parse_type(type_text: str) -> TypeEngine:
 
 def __parse_object_type_parameters(parameters):
     object_rows = {}
+    not_null_parts = NOT_NULL_STR.split(" ")
     for parameter in parameters:
         parameter_parts = tokenize_parameters(parameter, " ")
         if len(parameter_parts) >= 2:
@@ -178,40 +183,51 @@ def __parse_object_type_parameters(parameters):
                 return None
             not_null = (
                 len(parameter_parts) == 4
-                and parameter_parts[2] == "NOT"
-                and parameter_parts[3] == "NULL"
+                and parameter_parts[2] == not_null_parts[0]
+                and parameter_parts[3] == not_null_parts[1]
             )
             object_rows[key] = (value_type, not_null)
     return object_rows
 
 
-def __parse_map_type_parameters(parameters):
-    if len(parameters) != 2:
+def __parse_nullable_parameter(parameters):
+    if len(parameters) < 1:
+        return {}
+    elif len(parameters) > 1:
         return None
-
-    key_type_str = parameters[0]
-    value_type_str = parameters[1]
-    not_null_str = "NOT NULL"
-    not_null = False
+    parameter_str = parameters[0]
+    is_not_null = False
     if (
-        len(value_type_str) >= len(not_null_str)
-        and value_type_str[-len(not_null_str) :] == not_null_str
+        len(parameter_str) >= len(NOT_NULL_STR)
+        and parameter_str[-len(NOT_NULL_STR) :] == NOT_NULL_STR
     ):
-        not_null = True
-        value_type_str = value_type_str[: -len(not_null_str) - 1]
+        is_not_null = True
+        parameter_str = parameter_str[: -len(NOT_NULL_STR) - 1]
 
-    key_type: TypeEngine = parse_type(key_type_str)
-    value_type: TypeEngine = parse_type(value_type_str)
-    if isinstance(key_type, NullType) or isinstance(value_type, NullType):
+    value_type: TypeEngine = parse_type(parameter_str)
+    if isinstance(value_type, NullType):
         return None
 
     return {
-        "key_type": key_type,
         "value_type": value_type,
-        "not_null": not_null,
+        "not_null": is_not_null,
     }
 
 
+def __parse_map_type_parameters(parameters):
+    if len(parameters) != 2:
+        return None
+
+    key_type_str = parameters[0]
+    value_type_str = parameters[1]
+    key_type: TypeEngine = parse_type(key_type_str)
+    value_type = __parse_nullable_parameter([value_type_str])
+    if isinstance(value_type, NullType) or isinstance(key_type, NullType):
+        return None
+
+    return {"key_type": key_type, **value_type}
+
+
 def __parse_type_with_length_parameters(parameters):
     return (
         {"length": int(parameters[0])}

tests/__snapshots__/test_structured_datatypes.ambr

@@ -11,6 +11,20 @@
 # name: test_compile_table_with_structured_data_type[structured_type1]
   'CREATE TABLE clustered_user (\t"Id" INTEGER NOT NULL AUTOINCREMENT, \tname OBJECT(key1 VARCHAR(16777216), key2 DECIMAL(10, 0)), \tPRIMARY KEY ("Id"))'
 # ---
+# name: test_compile_table_with_structured_data_type[structured_type2]
+  'CREATE TABLE clustered_user (\t"Id" INTEGER NOT NULL AUTOINCREMENT, \tname ARRAY(MAP(DECIMAL(10, 0), VARCHAR(16777216))), \tPRIMARY KEY ("Id"))'
+# ---
+# name: test_insert_array
+  list([
+    (1, '[\n  "item1",\n  "item2"\n]'),
+  ])
+# ---
+# name: test_insert_array_orm
+  '''
+  002014 (22000): SQL compilation error:
+  Invalid expression [CAST(ARRAY_CONSTRUCT('item1', 'item2') AS ARRAY(VARCHAR(16777216)))] in VALUES clause
+  '''
+# ---
 # name: test_compile_table_with_structured_data_type[structured_type2]
   'CREATE TABLE clustered_user (\t"Id" INTEGER NOT NULL AUTOINCREMENT, \tname OBJECT(key1 VARCHAR(16777216), key2 DECIMAL(10, 0)), \tPRIMARY KEY ("Id"))'
 # ---
@@ -166,6 +180,35 @@
     }),
   ])
 # ---
+# name: test_inspect_structured_data_types[structured_type3-ARRAY]
+  list([
+    dict({
+      'autoincrement': True,
+      'comment': None,
+      'default': None,
+      'identity': dict({
+        'increment': 1,
+        'start': 1,
+      }),
+      'name': 'id',
+      'nullable': False,
+      'primary_key': True,
+      'type': _CUSTOM_DECIMAL(precision=10, scale=0),
+    }),
+    dict({
+      'autoincrement': False,
+      'comment': None,
+      'default': None,
+      'name': 'structured_type_col',
+      'nullable': True,
+      'primary_key': False,
+      'type': ARRAY(value_type=VARCHAR(length=16777216)),
+    }),
+  ])
+# ---
+# name: test_reflect_structured_data_types[ARRAY(MAP(NUMBER(10, 0), VARCHAR))]
+  "CREATE ICEBERG TABLE test_reflect_st_types (\tid DECIMAL(38, 0) NOT NULL, \tstructured_type_col ARRAY(MAP(DECIMAL(10, 0), VARCHAR(16777216))), \tCONSTRAINT constraint_name PRIMARY KEY (id))\tCATALOG = 'SNOWFLAKE'"
+# ---
 # name: test_reflect_structured_data_types[MAP(NUMBER(10, 0), MAP(NUMBER(10, 0), VARCHAR))]
   "CREATE ICEBERG TABLE test_reflect_st_types (\tid DECIMAL(38, 0) NOT NULL, \tstructured_type_col MAP(DECIMAL(10, 0), MAP(DECIMAL(10, 0), VARCHAR(16777216))), \tCONSTRAINT constraint_name PRIMARY KEY (id))\tCATALOG = 'SNOWFLAKE'"
 # ---
@@ -175,6 +218,12 @@
 # name: test_reflect_structured_data_types[OBJECT(key1 VARCHAR, key2 NUMBER(10, 0))]
   "CREATE ICEBERG TABLE test_reflect_st_types (\tid DECIMAL(38, 0) NOT NULL, \tstructured_type_col OBJECT(key1 VARCHAR(16777216), key2 DECIMAL(10, 0)), \tCONSTRAINT constraint_name PRIMARY KEY (id))\tCATALOG = 'SNOWFLAKE'"
 # ---
+# name: test_select_array_orm
+  list([
+    (1, '[\n  "item3",\n  "item4"\n]'),
+    (2, '[\n  "item1",\n  "item2"\n]'),
+  ])
+# ---
 # name: test_select_map_orm
   list([
     (1, '{\n  "100": "item1",\n  "200": "item2"\n}'),