refactor(snowflake): get query schema using dscribe last_query_id();

ibis/backends/base/sql/glot/datatypes.py

@@ -220,6 +220,14 @@ def _from_sqlglot_TIMESTAMPTZ(cls, scale=None) -> dt.Timestamp:
             nullable=cls.default_nullable,
         )
 
+    @classmethod
+    def _from_sqlglot_TIMESTAMPLTZ(cls, scale=None) -> dt.Timestamp:
+        return dt.Timestamp(
+            timezone="UTC",
+            scale=cls.default_temporal_scale if scale is None else int(scale.this.this),
+            nullable=cls.default_nullable,
+        )
+
     @classmethod
     def _from_sqlglot_INTERVAL(
         cls, precision: sge.DataTypeParam | None = None
@@ -371,6 +379,23 @@ class OracleType(SqlglotType):
 
 class SnowflakeType(SqlglotType):
     dialect = "snowflake"
+    default_temporal_scale = 9
+
+    @classmethod
+    def _from_sqlglot_FLOAT(cls) -> dt.Float64:
+        return dt.Float64(nullable=cls.default_nullable)
+
+    @classmethod
+    def _from_sqlglot_DECIMAL(cls, precision=None, scale=None) -> dt.Decimal:
+        if scale is None or int(scale.this.this) == 0:
+            return dt.Int64(nullable=cls.default_nullable)
+        else:
+            return super()._from_sqlglot_DECIMAL(precision, scale)
+
+    @classmethod
+    def _from_sqlglot_ARRAY(cls, value_type=None) -> dt.Array:
+        assert value_type is None
+        return dt.Array(dt.json, nullable=cls.default_nullable)
 
 
 class SQLiteType(SqlglotType):

ibis/backends/snowflake/__init__.py

@@ -19,7 +19,6 @@
 
 import pyarrow as pa
 import sqlalchemy as sa
-from snowflake.connector.constants import FIELD_ID_TO_NAME
 from snowflake.sqlalchemy import ARRAY, DOUBLE, OBJECT, URL
 from sqlalchemy.ext.compiler import compiles
 
@@ -409,13 +408,15 @@ def _make_batch_iter(
             )
 
     def _metadata(self, query: str) -> Iterable[tuple[str, dt.DataType]]:
-        with self.begin() as con, con.connection.cursor() as cur:
-            result = cur.describe(query)
-
-        for name, type_code, _, _, _, _, is_nullable in result:
-            typ_name = FIELD_ID_TO_NAME[type_code]
-            typ = SnowflakeType.from_string(typ_name)
-            yield name, typ.copy(nullable=is_nullable)
+        with self.begin() as con:
+            con.exec_driver_sql(query)
+            result = con.exec_driver_sql("DESC RESULT last_query_id()").mappings().all()
+
+        for field in result:
+            name = field["name"]
+            type_string = field["type"]
+            is_nullable = field["null?"] == "Y"
+            yield name, SnowflakeType.from_string(type_string, nullable=is_nullable)
 
     def list_databases(self, like: str | None = None) -> list[str]:
         with self.begin() as con:

ibis/backends/snowflake/tests/test_datatypes.py

@@ -5,7 +5,7 @@
 
 import ibis
 import ibis.expr.datatypes as dt
-from ibis.backends.snowflake.datatypes import parse
+from ibis.backends.snowflake.datatypes import SnowflakeType
 from ibis.backends.snowflake.tests.conftest import _get_url
 from ibis.util import gen_name
 
@@ -35,7 +35,7 @@
     ],
 )
 def test_parse(snowflake_type, ibis_type):
-    assert parse(snowflake_type.upper()) == ibis_type
+    assert SnowflakeType.from_string(snowflake_type.upper()) == ibis_type
 
 
 @pytest.fixture(scope="module")