Metadata-Version: 1.0
Name: yoyo-migrations
Version: 1
Summary: Database schema migration tool, using SQL and DB-API
Home-page: UNKNOWN
Author: Oliver Cope
Author-email: oliver@redgecko.org
License: BSD
Description: Yoyo-migrations
        ===============
        
        Yoyo-migrations is a database schema migration tool using plain SQL and the
        DB-API.
        
        What does yoyo-migrations do?
        -----------------------------
        
        As database applications evolve, changes to the database schema are often
        required. These can usually be written as one-off SQL scripts containing
        CREATE/ALTER table statements (although any SQL or python script may be used
        with yoyo-migrations).
        
        Yoyo-migrations provides a command line tool for reading a directory of such
        scripts and applying them to your database as required.
        
        Database support
        ----------------
        
        PostgreSQL, MySQL and SQLite databases are supported.
        
        
        Usage
        -----
        
        Yoyo-migrations is usually invoked as a command line script.
        
        Examples:
        
        Read all migrations from directory ``migrations`` and apply them to a PostgreSQL database::
        
        yoyo-migrate apply ./migrations/ postgres://user:password@localhost/database
        
        Rollback migrations previously applied to a MySQL database::
        
        yoyo-migrate rollback ./migrations/ mysql://user:password@localhost/database
        
        Reapply (ie rollback then apply again) migrations to a SQLite database at location ``/home/sheila/important-data.db``::
        
        yoyo-migrate reapply ./migrations/ sqlite:////home/sheila/important-data.db
        
        By default, yoyo-migrations starts in an interactive mode, prompting you for
        each migration file before applying it, making it easy to choose which
        migrations to apply and rollback.
        
        The migrations directory should contain a series of migration scripts. Each
        migration script is a python file (``.py``) containing a series of steps. Each
        step should comprise a migration query and (optionally) a rollback query. For
        example::
        
        #
        # file: migrations/0001.create-foo.py
        #
        step(
        "CREATE TABLE foo (id INT, bar VARCHAR(20), PRIMARY KEY (id))",
        "DROP TABLE foo",
        )
        
        The filename of each file (without the .py extension) is used as the identifier
        for each migration. Migrations are applied in filename order, so it's useful to
        name your files using a date (eg '20090115-xyz.py') or with another incrementing
        number.
        
        yoyo-migrate creates a table in your target database, ``_yoyo_migration``, to
        track which migrations have been applied.
        
        Steps may also take an optional argument ``ignore_errors``, which must be one
        of ``apply``, ``rollback``, or ``all``. If in the previous example the table
        foo might have already been created by another means, we could add
        ``ignore_errors='apply'`` to the step to allow the migrations to continue
        regardless::
        
        #
        # file: 0001.create-foo.py
        #
        step(
        "CREATE TABLE foo (id INT, bar VARCHAR(20), PRIMARY KEY (id))",
        "DROP TABLE foo",
        ignore_errors='apply',
        )
        
        Steps can also be python callable objects that take a database connection as
        their single argument. For example::
        
        #
        # file: 0002.update_keys.py
        #
        def do_step(conn):
        cursor = conn.cursor()
        cursor.execute(
        "INSERT INTO sysinfo "
        " (osname, hostname, release, version, arch)"
        " VALUES (%s, %s, %s, %s, %s %s)",
        os.uname()
        )
        step(do_step)
        
        Password security
        -----------------
        
        You normally specify your database username and password as part of the
        database connection string on the command line. On a multi-user machine, other
        users could view your database password in the process list.
        
        The ``-p`` or ``--prompt-password`` flag causes yoyo-migrate to prompt
        for a password, ignoring any password specified in the connection string.
        This password will not be available to other users via the system's process list.
        
        Connection string caching
        -------------------------
        
        The first time you run ``yoyo-migrate`` on a new set of migrations, you will be
        asked if you want to cache the database connection string in a file
        called ``.yoyo-migrate`` in the migrations directory.
        
        This cache is local to the migrations directory, so subsequent runs
        on the same migration set do not need the database connection string to be
        specified.
        
        This saves typing, avoids your database username and password showing in process listings and
        lessens the risk of accidentally running ``yoyo-migrate`` on the wrong
        database (ie by re-running an earlier ``yoyo-migrate`` entry in your command
        history when you have moved to a different directory).
        
        If you do not want this cache file to be used, add the ``--no-cache`` parameter
        to the command line options.
        
Platform: UNKNOWN
