Sqlalchemy-cratedb

- Added support for `crate_index` and `nullable` attributes in
ORM column definitions.

- Added support for converting `TIMESTAMP` columns to timezone-aware
`datetime` objects, using the new `time_zone` keyword argument.

- Added a generic data type converter to the `Cursor` object, for converting
fetched data from CrateDB data types to Python data types.

- Fixed generating appropriate syntax for OFFSET/LIMIT clauses. It was possible
that SQL statement clauses like `LIMIT -1` could have been generated. Both
PostgreSQL and CrateDB only accept `LIMIT ALL` instead.

- Added support for ORM computed columns

- Improved `CrateDialect.get_pk_constraint` to be compatible
with breaking changes in CrateDB >=5.1.0.

- Added support for Python 3.9 and 3.10.

- Dropped support for Python 3.4, 3.5 and 3.6.

- Dropped support for SQLAlchemy 1.1 and 1.2.

- Dropped support for CrateDB < 2.0.0.

- Added support for enabling SSL using SQLAlchemy DB URI with parameter
`?ssl=true`.

- Added support for SQLAlchemy 1.4

Notes

For learning about the transition to SQLAlchemy 1.4, we recommend the
corresponding documentation [What’s New in SQLAlchemy 1.4?].

Breaking changes

Textual column expressions
SQLAlchemy 1.4 became stricter on some details. It requires to wrap [CrateDB
system columns] like `_score` in a [SQLAlchemy literal_column] type.
Before, it was possible to use a query like this:

session.query(Character.name, '_score')

It must now be written like:

session.query(Character.name, sa.literal_column('_score'))

Otherwise, SQLAlchemy will complain like:

sqlalchemy.exc.ArgumentError: Textual column expression '_score' should be
explicitly declared with text('_score'), or use column('_score') for more
specificity


[CrateDB system columns]: https://cratedb.com/docs/crate/reference/en/4.8/general/ddl/system-columns.html
[SQLAlchemy literal_column]: https://docs.sqlalchemy.org/en/14/core/sqlelement.html#sqlalchemy.sql.expression.literal_column
[What’s New in SQLAlchemy 1.4?]: https://docs.sqlalchemy.org/en/14/changelog/migration_14.html

- Propagate connect parameter `pool_size` to urllib3 as `maxsize` parameter
in order to make the connection pool size configurable.

- Added support for the `RETURNING` clause. This requires CrateDB 4.2 or greater.
In case you use any server side generated columns in your primary key constraint
with earlier CrateDB versions, you can turn off this feature by passing
`implicit_returning=False` in the `create_engine()` call.
- Added support for `geo_point` and `geo_json` types