sqlalchemy-explore 0.1.2

Utilities for working with pre-existing databases using SQLAlchemy

sqlalchemy_explore

tools for exploring databases using sqlalchemy

installation

pip install sqlalchemy_explore

Features

1. Base class for relective usage of classes
2. Database exploration tool

Base class for relective usage of classes

Usage

Make the declarative base clsss provided by SQLAlchemy derive from sqlalchemy_explore.ReflectiveMixin

import sqlalchemy_explore
Base = declarative_base(cls=cls=sqlalchemy_explore.ReflectiveMixin)

now all of your instances support the following functions:

• sa_keys() - returns the keys/column names that SQLAlchemy is mapping
• sa_dict() - return key/value pairs of all the columns in the object
• __repr__() - str represetation of the object that includes all the columns

Example

Imagine you have a couple of classes represnting tables in SQLAlchemy

Base = declarative_base()

class Artist(Base):
    __tablename__ = 'artists'

    ArtistId = Column(Integer, primary_key=True)
    Name = Column(NVARCHAR(120))


class Album(Base):
    __tablename__ = 'albums'

    AlbumId = Column(Integer, primary_key=True)
    Title = Column(NVARCHAR(160), nullable=False)
    ArtistId = Column(ForeignKey('artists.ArtistId'), nullable=False, index=True)

    artist = relationship('Artist')

dynamiclly iterating through the column names and values of a mapped object requires a lot of boiler plate code. but sqlalchemy_explore lets you do this very easily. to enable it on your classes

import sqlalchemy_explore
Base = declarative_base(cls=cls=sqlalchemy_explore.ReflectiveMixin)

and continue having your classes inherit from Base.

now formatted printing is avaiable to all your objects

artist = Artist(ArtistId=1, Name='Norah Jones')
print('hello', artist)

output:

hello Artist(ArtistId=1, Name='Norah Jones')

album = Album(AlbumId=1, Title='Come Away with Me', ArtistId=artist.ArtistId)
print('buy', album)

output:

buy Album(AlbumId=1, Title='Come Away with Me', ArtistId=1)

also you can iterate over a dict of column names/values in your object

print(album.sa_dict())

output:

{'AlbumId': 1, 'Title': 'Come Away with Me', 'ArtistId': 1}

Database exploration tool

when using sqlalchemy_explore as a tool, it can dump the schema of database tables to help you figure out what's in the DB

At the minimum, you have to give sqlalchemy_explore a database URL or a path to a local sqlite database. The URL is passed directly to SQLAlchemy’s create_engine() method so please refer to SQLAlchemy’s documentation for instructions on how to construct a proper URL.

Examples:

python -m sqlalchemy_explore database.db
python -m sqlalchemy_explore postgresql:///some_local_db
python -m sqlalchemy_explore mysql+oursql://user:password@localhost/dbname
python -m sqlalchemy_explore sqlite:///database.db