#!/usr/bin/env python

"""
Upgrade a database schema.

Usage: dbupgrade [OPTIONS] [-l API_LEVEL|-L] DBNAME SCHEMA DIRECTORY

Upgrade the given SCHEMA in the database specified as DBNAME with SQL scripts
from DIRECTORY. DIRECTORY is searched for all files with the ".sql" suffix.
These files are SQL scripts with a special header sections like this::

    -- Schema: my-db-schema
    -- Version: 25
    -- API-Level: 3
    -- Dialect: postgres

    CREATE TABLE ...

The following headers are required:

:Schema:
    Name of the schema to update.
:Dialect:
    Database dialect of this script. Use SQLalchemy's database
    URL scheme identifier, e.g. "postgres" or "sqlite".
:Version:
    The new version of the schema after this script was applied.
    It is an error if two scripts have the same schema, dialect, and version.
:API-Level:
    The new API level of the schema after this script was applied.
    For a given schema, the API level of a subsequent version must either be
    equal or higher by one than the API level of the preceding version. For
    example, if script version 44 has API level 3, script version 45 must
    have API level 3 or 4.

The database must contain a table "db_config" with three columns: "schema",
"version", and "api_level". If this table does not exist, it is created.
This table must contain exactly one row for the given schema. If this row
does not exist, it is created with version and api_level initially set to 0.

The current version and API level of the schema are requested from the
database and all scripts with a higher version number are applied, in order.
If there are any version numbers missing, the script will stop after the
last version before the missing version.

Unless the -l or -L option is supplied, only scripts that do not increase the
API level will be applied. If the -l option is given, all scripts up to the
given API level will be applied. -L will apply all scripts without regard to
the API level.

Each script is executed in a seperate transaction. If a script fails, all
changes in that script will be rolled back and the script will stop with
an error message and a non-zero return status.

"""

from dbupgrade.main import main

main()
