On Fri, May 1, 2020, at 10:55 AM, bb1898 wrote: > Using Python 3.8.2, SQLAlchemy 1.3.16 on Windows 10. > > From version 3.31.0 (2020-01-22) SQLite supports generated columns; > documentation: https://sqlite.org/gencol.html > So I tried to create a table in a SQLite database using this table definition: > > class MieterRechnung(Base): > > __tablename__ = "mieter_rechnung" > > idv = sa.Column(sa.Integer, primary_key=True) > idr = sa.Column(sa.Integer, sa.ForeignKey("rechnung.idr")) > idp = sa.Column(sa.Integer, sa.ForeignKey("person.idp")) > monate = sa.Column(sa.Numeric(4, 1, asdecimal=False), nullable=False) > status = sa.Column(sa.String, nullable=False, default="durch") > basis = sa.Column(sa.Numeric(8, 2, asdecimal=False), nullable=False) > gezahlt = sa.Column(sa.Numeric(8, 2, asdecimal=False), nullable=False) > drittelpreis = sa.Column(sa.Computed("basis / 3")) > diff = sa.Column(sa.Computed("gezahlt - drittelpreis")) > > rechnung = orm.relationship("Rechnung", back_populates="personen") > person = orm.relationship("Person", back_populates="rechnungen") > > > I did wonder why SQLite isn't mentioned in the list of database systems > supporting computed columns, but tried anyway. It really doesn't work, I get > this exception: > > File "c:\Program > Files\Python38\Lib\site-packages\sqlalchemy\sql\compiler.py", line 2894, in > visit_create_table > processed = self.process( > File "c:\Program > Files\Python38\Lib\site-packages\sqlalchemy\sql\compiler.py", line 350, in > process > return obj._compiler_dispatch(self, **kwargs) > File "c:\Program > Files\Python38\Lib\site-packages\sqlalchemy\sql\visitors.py", line 95, in > _compiler_dispatch > return meth(self, **kw) > File "c:\Program > Files\Python38\Lib\site-packages\sqlalchemy\sql\compiler.py", line 2928, in > visit_create_column > text = self.get_column_specification(column, first_pk=first_pk) > File "c:\Program > Files\Python38\Lib\site-packages\sqlalchemy\dialects\sqlite\base.py", line > 1077, in get_column_specification > raise exc.CompileError("SQLite does not support computed columns")
OK well, 2020-1-22 was just four months ago, so SQLAlchemy certainly needs some time to add support for new database features. Please open an issue at github.com/sqlalchemy/sqlalchemy/issues . > > sqlalchemy.exc.CompileError: SQLite does not support computed columns > > The above exception was the direct cause of the following exception: > > File "D:\Sibylle\Src\PythonVersuche\sqlalchemy\serientest_start.py", line 92, > in <module> > main() > File "D:\Sibylle\Src\PythonVersuche\sqlalchemy\serientest_start.py", line 87, > in main > scl.create_database() > File > "D:\Sibylle\Src\PythonVersuche\sqlalchemy\serientest_pyp\serientest_classes.py", > line 95, in create_database > sclass = _create_connection(_TEST_CONNSTR, createdb=True) > File > "D:\Sibylle\Src\PythonVersuche\sqlalchemy\serientest_pyp\serientest_classes.py", > line 82, in _create_connection > Base.metadata.create_all(engine) > File "c:\Program Files\Python38\Lib\site-packages\sqlalchemy\sql\schema.py", > line 4320, in create_all > bind._run_visitor( > File "c:\Program Files\Python38\Lib\site-packages\sqlalchemy\engine\base.py", > line 2058, in _run_visitor > conn._run_visitor(visitorcallable, element, **kwargs) > File "c:\Program Files\Python38\Lib\site-packages\sqlalchemy\engine\base.py", > line 1627, in _run_visitor > visitorcallable(self.dialect, self, **kwargs).traverse_single(element) > File "c:\Program > Files\Python38\Lib\site-packages\sqlalchemy\sql\visitors.py", line 144, in > traverse_single > return meth(obj, **kw) > File "c:\Program Files\Python38\Lib\site-packages\sqlalchemy\sql\ddl.py", > line 777, in visit_metadata > self.traverse_single( > File "c:\Program > Files\Python38\Lib\site-packages\sqlalchemy\sql\visitors.py", line 144, in > traverse_single > return meth(obj, **kw) > File "c:\Program Files\Python38\Lib\site-packages\sqlalchemy\sql\ddl.py", > line 821, in visit_table > self.connection.execute( > File "c:\Program Files\Python38\Lib\site-packages\sqlalchemy\engine\base.py", > line 984, in execute > return meth(self, multiparams, params) > File "c:\Program Files\Python38\Lib\site-packages\sqlalchemy\sql\ddl.py", > line 72, in _execute_on_connection > return connection._execute_ddl(self, multiparams, params) > File "c:\Program Files\Python38\Lib\site-packages\sqlalchemy\engine\base.py", > line 1035, in _execute_ddl > compiled = ddl.compile( > File "<string>", line 1, in <lambda> > File "c:\Program > Files\Python38\Lib\site-packages\sqlalchemy\sql\elements.py", line 468, in > compile > return self._compiler(dialect, bind=bind, **kw) > File "c:\Program Files\Python38\Lib\site-packages\sqlalchemy\sql\ddl.py", > line 29, in _compiler > return dialect.ddl_compiler(dialect, self, **kw) > File "c:\Program > Files\Python38\Lib\site-packages\sqlalchemy\sql\compiler.py", line 319, in > __init__ > self.string = self.process(self.statement, **compile_kwargs) > File "c:\Program > Files\Python38\Lib\site-packages\sqlalchemy\sql\compiler.py", line 350, in > process > return obj._compiler_dispatch(self, **kwargs) > File "c:\Program > Files\Python38\Lib\site-packages\sqlalchemy\sql\visitors.py", line 95, in > _compiler_dispatch > return meth(self, **kw) > File "c:\Program > Files\Python38\Lib\site-packages\sqlalchemy\sql\compiler.py", line 2904, in > visit_create_table > util.raise_( > File "c:\Program Files\Python38\Lib\site-packages\sqlalchemy\util\compat.py", > line 178, in raise_ > raise exception > > sqlalchemy.exc.CompileError: (in table 'mieter_rechnung', column 'diff'): > SQLite does not support computed columns > > -- > SQLAlchemy - > The Python SQL Toolkit and Object Relational Mapper > > http://www.sqlalchemy.org/ > > To post example code, please provide an MCVE: Minimal, Complete, and > Verifiable Example. See http://stackoverflow.com/help/mcve for a full > description. > --- > You received this message because you are subscribed to the Google Groups > "sqlalchemy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sqlalchemy+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sqlalchemy/35c5806d-5e5e-4991-8d64-ae1639e32378%40googlegroups.com > > <https://groups.google.com/d/msgid/sqlalchemy/35c5806d-5e5e-4991-8d64-ae1639e32378%40googlegroups.com?utm_medium=email&utm_source=footer>. -- SQLAlchemy - The Python SQL Toolkit and Object Relational Mapper http://www.sqlalchemy.org/ To post example code, please provide an MCVE: Minimal, Complete, and Verifiable Example. See http://stackoverflow.com/help/mcve for a full description. --- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sqlalchemy/f24238a1-5cd3-4fb0-b386-353bb4a384db%40www.fastmail.com.
