SQLAlchemy/DDL: Allow to turn off column store

CHANGES.txt

@@ -5,6 +5,9 @@ Changes for crate
 Unreleased
 ==========
 
+- SQLAlchemy DDL: Allow turning off column store using ``crate_columnstore=False``.
+  Thanks, @fetzerms.
+
 
 2023/04/18 0.31.1
 =================

docs/sqlalchemy.rst

@@ -205,6 +205,7 @@ system <sa:orm_declarative_mapping>`:
     ...     more_details = sa.Column(types.ObjectArray)
     ...     name_ft = sa.Column(sa.String)
     ...     quote_ft = sa.Column(sa.String)
+    ...     even_more_details = sa.Column(sa.String, crate_columnstore=False)
     ...
     ...     __mapper_args__ = {
     ...         'exclude_properties': ['name_ft', 'quote_ft']
@@ -220,6 +221,7 @@ In this example, we:
 - Use standard SQLAlchemy types for the ``id``, ``name``, and ``quote`` columns
 - Use ``nullable=False`` to define a ``NOT NULL`` constraint
 - Disable indexing of the ``name`` column using ``crate_index=False``
+- Disable the columnstore of the ``even_more_details`` column using ``crate_columnstore=False``
 - Define a computed column ``name_normalized`` (based on ``name``) that
   translates into a generated column
 - Use the `Object`_ extension type for the ``details`` column

src/crate/client/sqlalchemy/compiler.py

@@ -25,6 +25,7 @@
 import sqlalchemy as sa
 from sqlalchemy.dialects.postgresql.base import PGCompiler
 from sqlalchemy.sql import compiler
+from sqlalchemy.types import String
 from .types import MutableDict, _Craty, Geopoint, Geoshape
 from .sa_version import SA_VERSION, SA_1_4
 
@@ -128,6 +129,14 @@ def get_column_specification(self, column, **kwargs):
 
             colspec += " INDEX OFF"
 
+        if column.dialect_options['crate'].get('columnstore') is False:
+            if not isinstance(column.type, (String, )):
+                raise sa.exc.CompileError(
+                    "Controlling the columnstore is only allowed for STRING columns"
+                )
+
+            colspec += " STORAGE WITH (columnstore = false)"
+
         return colspec
 
     def visit_computed_column(self, generated):

src/crate/client/sqlalchemy/tests/create_table_test.py

@@ -232,3 +232,30 @@ class DummyTable(self.Base):
             a = sa.Column(Geopoint, crate_index=False)
         with self.assertRaises(sa.exc.CompileError):
             self.Base.metadata.create_all(bind=self.engine)
+
+    def test_text_column_without_columnstore(self):
+        class DummyTable(self.Base):
+            __tablename__ = 't'
+            pk = sa.Column(sa.String, primary_key=True)
+            a = sa.Column(sa.String, crate_columnstore=False)
+            b = sa.Column(sa.String, crate_columnstore=True)
+            c = sa.Column(sa.String)
+
+        self.Base.metadata.create_all(bind=self.engine)
+
+        fake_cursor.execute.assert_called_with(
+            ('\nCREATE TABLE t (\n\t'
+             'pk STRING NOT NULL, \n\t'
+             'a STRING STORAGE WITH (columnstore = false), \n\t'
+             'b STRING, \n\t'
+             'c STRING, \n\t'
+             'PRIMARY KEY (pk)\n)\n\n'), ())
+
+    def test_non_text_column_without_columnstore(self):
+        class DummyTable(self.Base):
+            __tablename__ = 't'
+            pk = sa.Column(sa.String, primary_key=True)
+            a = sa.Column(sa.Integer, crate_columnstore=False)
+
+        with self.assertRaises(sa.exc.CompileError):
+            self.Base.metadata.create_all(bind=self.engine)