sql.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
# @Version     : Python 3.11.4
# @Software    : Sublime Text 4
# @Author      : StudentCWZ
# @Email       : StudentCWZ@outlook.com
# @Date        : 2023/10/29 00:36
# @File        : sql.py
# @Description : Defines the DatabaseUri class for generating SQLAlchemy database connection strings.
"""


class DatabaseUri:
    """
    A utility class to generate SQLAlchemy database connection strings for various types of databases.

    Args:
        db_type (str): The type of the database. It could be "mysql", "postgresql", "oracle", "sqlite".
        username (str, optional): The username of the database. Not required for "sqlite".
        password (str, optional): The password of the database. Not required for "sqlite".
        host (str, optional): The host of the database. Not required for "sqlite".
        port (str, optional): The port of the database. Not required for "sqlite".
        db (str, optional): The database name. For "sqlite", it is the path to the database file.
        driver (str, optional): The python library to connect to the database. Not required but could be provided.
    """
    def __init__(self, db_type: str, username: str = None, password: str = None,
                 host: str = None, port: str = None, db: str = None, driver: str = None) -> None:
        self.db_type = db_type
        self.username = username
        self.password = password
        self.host = host
        self.port = port
        self.db = db
        self.driver = driver

    def create(self) -> str:
        """
        Creates a SQLAlchemy engine string for the specified database.

        Returns:
            str: A SQLAlchemy engine string.
        """
        # SQLite database only requires a path to the database file
        if self.db_type == 'sqlite':
            return f'{self.db_type}:///{self.db}'
        else:
            # Other databases require a full connection string with optional driver
            if self.driver:
                return (f'{self.db_type}+{self.driver}://'
                        f'{self.username}:{self.password}@{self.host}:{self.port}/{self.db}')
            else:
                return f'{self.db_type}://{self.username}:{self.password}@{self.host}:{self.port}/{self.db}'

    def __repr__(self):
        """
        Returns a formal string representation of the DatabaseUri object.

        Returns:
            str: The formal string representation of the DatabaseUri object.
        """
        return f'<DatabaseUri({self.db_type})>'

    def __str__(self):
        """
        Returns a string representation of the DatabaseUri object, which is the SQLAlchemy engine string.

        Returns:
            str: The string representation of the DatabaseUri object.
        """
        return self.create()