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Type Checking for Class Row Factory

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
20/100
Issue type
Feature
Clarity
Mostly clear
Activity status
Stale
Tech stack
python
Domain
databases

Research direction

Review Issue #42 and PR #57 first, since the proposed solution is described there. Then inspect comdb2.dataclasses.class_row_factory and compare the BaseRowFactoryClass example with the stated type-checking concern. Done means confirming whether the PR fully addresses validation for dataclass attributes and database output.

Written by the indexing model from the issue text.

Description

As described in Issue #42 there was a proposed solution for having a Class Row Factory. Alongside the conversations happened there, there was a concern regarding type checking for the attributes of the class and output returned by the database. There doesn't seem to be a way to enforce type checking hence an extra __post_init__ method would be required within the class to enforce type checking. This can be overlooked by a lot of developers and can lead to a lot of type mismatches.

Solution

Define a Base class that our dataclasses can inherit. The Base class can have all the required methods for the validation etc.

The updated use of it can be described it here. The solution has been implemented on the PR #57

        >>> from dataclasses import dataclass
        >>> from comdb2.dataclasses.class_row_factory import BaseRowFactoryClass
        ...
        >>> @dataclass
        >>> class ABC(BaseRowFactoryClass):
        >>>     x: int
        >>>     y: int
        
        ...
        >>> conn.row_factory = ClassRowFactory(ABC)
        >>> row = conn.cursor().execute("select 1 as x, 2 as y").fetchone()
        >>> print(row)
        <>
        >>> print(row.x)
Dominant language
Python
Stars
29
Forks
28
Avg merge
11h 25m
Merged PRs (30d)
2

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  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

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