dblink 0.3.0

DBLink tools makes operation on exists table easier.

dblink

Aimed for easily using query, insert, update and delete with an exist table, the filter query syntax likes Django's. You can find out the simple usage in the code below.

Introduction

Suppose you have two tables: users and addresses created by:

CREATE TABLE users (
    id INTEGER NOT NULL,
    name VARCHAR(50),
    fullname VARCHAR(50),
    password VARCHAR(12),
    PRIMARY KEY (id)
);

CREATE TABLE addresses (
    id INTEGER NOT NULL,
    email_address VARCHAR NOT NULL,
    user_id INTEGER,
    PRIMARY KEY (id),
    FOREIGN KEY(user_id) REFERENCES users (id)
);

You can link to exist table in database using Database Urls.

from dblink import Database, Table
db = Database(url='sqlite:///:memory:')
user_table = Table('users', db)
# ...
db.close()

with Database(url='postgresql://scott:tiger@localhost/mydatabase') as db:
    address_table = Table('addresses', db)
    # ...

Here is a simple example.

"""
Suppose you have two table: users and addresses.
"""
from dblink import Database, Table


with Database('sqlite:///:memory:') as db:
    table_user = Table('users', db)
    table_address = Table('addresses', db)

    # show description
    print(table_user.description)
    print(table_address.description)

    # chain query, you can call delete on the single table result
    table_user.query.filter(id=1).one_or_none()

    table_user.query.filter(id__gte=2) \
                    .order_by('name') \
                    .values_list('id', 'name')

    table_user.query.filter(id__in=[1, 2, 3]) \
                    .filter(name__startswith='Yu').all()

    table_user.query.order_by('-name') \
                    .values_list('fullname', flat=True, distinct=True)

    table_user.query.distinct('name').values_list('name', flat=True)

    table_user.query.filter(id__in=[1, 2, 3]).delete()

    # join query
    table_user.join(table_address) \
              .filter(id__lt=10000) \
              .filter(email_address__contains='gmail') \
              .filter(**{'addresses.id__gte': 100}) \
              .values_list('user_id', 'name', 'email_address',
                           table_address.id, 'users.fullname')

    # get or insert
    instance, create = table_user.get_or_insert(id=1, name='jone')

    # single record operation.
    table_user.insert({'id': 1, 'name': 'YuJun', 'password': 'psw'})

    table_user.update({'id': 1, 'name': 'skyduy', 'password': 'psw'},
                      unique_fields=['id'], update_fields=['name', 'password'])

    table_user.insert_or_update(
        {'id': 1, 'name': 'skyduy', 'password': 'psw'},
        unique_fields=['id'], update_fields=['name', 'password']
    )

    table_user.delete({'id': 1, 'name': "I don't matter"},
                      unique_fields=['id'])

    # bulk operation
    items = [{'id': 1, 'name': 'yujun', 'password': 'haha'},
             {'id': 2, 'name': 'skyduy', 'password': 'aha'},]
    unique_fields = ['id']
    update_fields = ['name']
    table_user.bulk_insert(items)
    table_user.bulk_delete(items, unique_fields)
    table_user.bulk_update(items, unique_fields, update_fields)
    table_user.bulk_insert_or_update(items, unique_fields, update_fields)

History

V0.3.0 (2019/09/08)

• Update requirements for security.
• Fix the installation bugs on windows.

V0.2.1 (2018/05/09)

• Add encoding option.
• Improve package dependence.

V0.2.0 (2018/03/24)

• Bug fix.

  • Error closing cursor when operation on local sqlite db.
  • Bugs in bulk_insert_or_update.

• Improve Error tips.

V0.1.2 (2018/02/05)

• Initial release.