[IGNITE-22719] Python DB API Driver 3.0

• Type: Epic
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: platforms, python, thin client
• Labels: ignite-3 important
• Epic Name: Python DB API Driver 3.0
• Ignite Flags: Docs Required, Release Notes Required
• Assignee: Igor Sapego
• Reporter: Igor Sapego
• Created: 12/Jul/24 09:55
• Updated: 26/Nov/24 08:28

Description

Requirements

• The implementation of the Python DB API or the Driver should be implemented using Python 3;
• The Driver should comply with Python DB-API 2.0: https://peps.python.org/pep-0249/;
• Performance of the Driver should be similar to the performance of other clients and drivers, e.g. JDBC;
• The first implementation should be as simple as possible, but it should be functional and allow for improvements in future;
• Preferably the Driver should be designed in such a way that makes it possible in the future to extend Driver’s API and turn it into a full-fledged Python Client.

Code Reuse

It is proposed to re-use the protocol part, which is currently used by ODBC and JDBC drivers. Its functionality should be more than enough for implementation of the Driver, as the DB API is much simpler than both JDBC and ODBC.
It is also proposed to re-use C++ code for data packing-unpacking (protocol messages, binary tuples).
It’s important to point out that in most of the implementations of such drivers, C/C++ code is duplicated in Python, but the first implementation of our Driver won’t include duplication of C++ code for the sake of simplicity. This means, if the user won’t be able to compile our C++ code on their platform for any reason, they won’t be able to use our Driver.

Type Mapping

The implementation of the specification is pretty straightforward and there is no need to discuss implementation of methods in detail. The only part that should probably be discussed is a data type mapping.

The following type mapping is suggested for the Driver:

Ignite Type	DB API Type	Python Type
NIL	None	None
BOOLEAN	NUMBER	bool
INT8	NUMBER	int
INT16	NUMBER	int
INT32	NUMBER	int
INT64	NUMBER	int
FLOAT	NUMBER	float
DOUBLE	NUMBER	float
DECIMAL	NUMBER	decimal.Decimal
DATE	DATETIME	datetime.date
TIME	DATETIME	datetime.time
DATETIME	DATETIME	datetime.datetime
TIMESTAMP	NUMBER	Timestamp(float)
UUID	STRING	uuid.UUID
STRING	STRING	str
BYTE_ARRAY	BINARY	bytes
PERIOD	DATETIME	???
DURATION	DATETIME	datetime.timedelta