Automatic model code generator for SQLAlchemy
This is a tool that reads the structure of an existing database and generates the appropriate SQLAlchemy model code, using the declarative style if possible.
This tool was written as a replacement for sqlautocode
_, which was suffering from several issues
(including, but not limited to, incompatibility with Python 3 and the latest SQLAlchemy version).
.. _sqlautocode: http://code.google.com/p/sqlautocode/
PEP 8
_ compliant code.. _PEP 8: http://www.python.org/dev/peps/pep-0008/
To install, do::
pip install sqlacodegen
At the minimum, you have to give sqlacodegen a database URL. 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::
sqlacodegen postgresql:///some_local_db
sqlacodegen mysql+oursql://user:password@localhost/dbname
sqlacodegen sqlite:///database.db
To see the full list of options::
sqlacodegen --help
.. _create_engine(): http://docs.sqlalchemy.org/en/latest/core/engines.html#sqlalchemy.create_engine .. _SQLAlchemy's documentation: http://docs.sqlalchemy.org/en/latest/core/engines.html
Unless the --noclasses
option is used, sqlacodegen tries to generate declarative model classes
from each table. There are two circumstances in which a Table
is generated instead:
The table name (which is assumed to be in English) is converted to singular form using the
"inflect" library. Then, every underscore is removed while transforming the next letter to upper
case. For example, sales_invoices
becomes SalesInvoice
.
Relationships are detected based on existing foreign key constraints as follows:
A table is considered an association table if it satisfies all of the following conditions:
#. has exactly two foreign key constraints #. all its columns are involved in said constraints
Relationships are typically named based on the opposite class name. For example, if an Employee
class has a column named employer
which has a foreign key to Company.id
, the relationship
is named company
.
A special case for single column many-to-one and one-to-one relationships, however, is if the
column is named like employer_id
. Then the relationship is named employer
due to that
_id
suffix.
If more than one relationship would be created with the same name, the latter ones are appended numeric suffixes, starting from 1.
If you have problems or other questions, you can either:
SQLAlchemy Google group
_, or#sqlalchemy
channel on Freenode IRC
_.. _SQLAlchemy Google group: http://groups.google.com/group/sqlalchemy .. _Freenode IRC: http://freenode.net/irc_servers.shtml