Recipe for managing RDB schemas
Project description
This is a zc.buildout recipe that helps managing schema updates on relational databases.
It currently only supports PostgreSQL.
Defining a managed database
A managed database has to be created (CREATEDB) outside of this recipe. The recipe only takes care of initialising an existing database and upgrading the schema subsequently.
Part definitions look like:
[managed_db] recipe = gocept.rdbmanagement dbname = mydatabase eggs = projectegg schema = projectegg.schemadir host = localhost user = username password = apassword
Where
- dbname
is the name of the PostgreSQL database to work with
- eggs
is a list of egg requirements that should be activated before looking up the schema directory resource path
- schema
is a setuptools resource path that is a managed schema directory
Managed schema directories
A schema directory contains a set of SQL and Python files that are used to manage the schema for a database. A typical directory looks like this:
$ ls schemadir __init__.py init.sql precondition3.py update1.sql update2.sql update3.sql
Notice: A managed schema directory has to be a Python package.
init.sql
Creates the schema beginning from an empty database.
After init.sql the current generation will be set to the highest generation number as available from the update scripts. Therefore the init.sql always creates a current database schema and no updates will be run.
updateX.sql
Update scripts MUST start with a BEGIN statement and end with a COMMIT statement.
Update script X will be run from a database at generation X-1.
preconditionX.py
Script must contain a function called precondition which takes one parameter which is an open DB-API2-connection to the database.
Precondition script X will be run on a database at generation X-1.
Precondition script X has to raise an exception to indicate that the database MUST not be updated to generation X.
Changes
1.0 (2015-07-06)
Implement ability to use a password when accessing the database, requiring at least PostgreSQL 9.0 for this feature.
Require at least Python 2.7.
0.1.2
allow newer versions than exactely psycopg2==2.0.6
0.1.1
first public release
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