sb-db-common 1.0.1

A set of db wrappers

Db Common Lib

Mainly for myself, switching between different database providers all the time, I wanted a consistent interface.
Thats what this is for.
More consistent (Think ADO.NET) db connectivity

Overview

Links pgsql, mysql, mssql, oracle, sqlite and cockroachdb in a common interface.
Unit tests show usage.

This package focuses on connections and sessions (execute, fetch, transactions). It does not include an ORM, entity decorator, or repository layer; map rows and SQL yourself in your application.

Exposed API

Import from sb_db_common:

from sb_db_common import (
    SessionFactory, Session, PersistentSession,
    ConnectionBase, MySqlConnection, PgSqlConnection, MsSqlConnection, SqliteConnection,
    OracleConnection, CockroachConnection,
    ManagedCursor,
    DataException, DatatypeException,
    resolve_type,
)

Connections

ConnectionBase — Abstract base for all database connections. Holds connection_string, database, and connection. Subclasses implement start(), commit(), rollback(), execute(), execute_lastrowid(), fetch(), close(), and map_sql_value() (for mapping DB values to Python types). Use as a base when adding a new provider.

MySqlConnection, PgSqlConnection, MsSqlConnection, SqliteConnection, OracleConnection, CockroachConnection — Concrete connection classes for MySQL, PostgreSQL, SQL Server, SQLite, Oracle, and CockroachDB. Usually created via SessionFactory.get_connection(connection_string) rather than instantiated directly.

from sb_db_common import SessionFactory

conn = SessionFactory.get_connection("sqlite:///path/to/db.sqlite")
conn.start()
# ... use conn.execute(), conn.fetch(), etc. ...
conn.commit()
conn.close()

Session

Session — Context-managed database session. Opens the connection on __enter__, commits and closes on __exit__. Use for short-lived, transactional work.

with SessionFactory.connect("sqlite:///test.db") as session:
    session.execute("INSERT INTO test(name) VALUES (:name)", {"name": "alice"})
    id = session.execute_lastrowid("INSERT INTO test(name) VALUES (:name)", {"name": "bob"})
    row = session.fetch_one("SELECT * FROM test WHERE id = :id", {"id": id})
    val = session.fetch_scalar("SELECT COUNT(*) FROM test")
# commits and closes when the block ends

PersistentSession — Session that reuses a single global connection (e.g. for in-memory SQLite). Does not close the connection on exit; only commits. Use when you need one long-lived connection shared across multiple session blocks.

# First use: creates and keeps the connection
with SessionFactory.connect("sqlite:///memory") as session:
    session.execute("CREATE TABLE test(id INTEGER PRIMARY KEY, name TEXT)")
# Later: reuses same connection
with SessionFactory.connect("sqlite:///memory") as session:
    session.execute("INSERT INTO test(name) VALUES (:name)", {"name": "bob"})

SessionFactory — Creates sessions from connection strings. Call SessionFactory.register() once (e.g. at startup) so providers self-register. Use SessionFactory.connect(connection_string) to get a Session or PersistentSession.

SessionFactory.register()  # typically at app startup
with SessionFactory.connect("pgsql://user:pass@localhost/mydb") as session:
    session.execute("SELECT 1")

Infrastructure

ManagedCursor — Wrapper around a DB-API cursor that closes on context exit. Exposes execute(), executemany(), fetchall(), fetchone(), iteration, and properties like description (column names) and rowcount. Returned by Connection.fetch() / Session.fetch().

with SessionFactory.connect("sqlite:///test.db") as session:
    with session.fetch("SELECT id, name FROM test") as cursor:
        for row in cursor:
            print(row)
        # or: cursor.fetchall(), cursor.fetchone()

Utilities (sb_db_common.utils)

Helpers such as path/string utilities and resolve_type(type_name: str) -> type, which resolves a built-in name (e.g. "int") or a fully qualified type (e.g. "datetime.datetime"). Import from the package root:

from sb_db_common import resolve_type

t = resolve_type("datetime.datetime")

Exceptions

DataException — Base exception for data-layer errors (e.g. invalid connection string, invalid id).

DatatypeException — Subclass of DataException for type/conversion errors.

from sb_db_common import DataException, DatatypeException

try:
    SessionFactory.get_connection("unknown://x")
except DataException as e:
    print(e)

Usage

Connection string format is: <provider>://<username>:<password>@<host>/<database>
The supported providers are: sqlite, mysql, mssql, pgsql, oracle, cockroach

The providers self-register. Call SessionFactory.register() before use.

with SessionFactory.connect(<connection string>) as session:
    id = session.execute_lastrowid("insert into test(name) values (:name);", {"name": "bob"})
    session.execute("update test set name = :name where id = :id", {"id": id, "name": "bob1"})

The session closes and commits automatically when it goes out of scope.
For more control, manually call commit and rollback.

The queries are db specific, but the mechanisms are the same for all.
Major differences are the different field types, the parameter specification and in the use of identity columns across the different db's.
Remember to add returning <field> to the insert statement for pgsql or you won't get the identity back.

Differences

sqlite

CREATE TABLE test(
    id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, 
    name TEXT
);

INSERT INTO test(name) VALUES (:name)

mysql

CREATE TABLE test(
    id INT NOT NULL PRIMARY KEY AUTO_INCREMENT, 
    name VARCHAR(50) NULL
);

INSERT INTO test(name) VALUES (%(name)s);

pgsql

CREATE TABLE test(
    id INT NOT NULL PRIMARY KEY GENERATED ALWAYS AS IDENTITY, 
    name VARCHAR(50) NULL
 );

INSERT INTO test(name) VALUES (%(name)s) RETURNING id;

oracle

CREATE TABLE test(
    id NUMBER GENERATED ALWAYS AS IDENTITY PRIMARY KEY, 
    name VARCHAR(50) NULL
 );

INSERT INTO test(name) VALUES (:name) RETURNING id;

mssql

CREATE TABLE test(
    id INT IDENTITY(1,1) NOT NULL PRIMARY KEY, 
    name VARCHAR(50) NULL
 );

INSERT INTO test(name) output inserted.id VALUES (%(name)s);

Integrated security is supported, either by passing in a windows username / password, or by setting trusted_connection=yes - username / password are then optional, it will then ignore them if provided, and will use the current logged in user.

Building

python -m build

Deploying

python -m twine upload --repository pypi dist/*