NAME

DBIx::Migration::Directories::Database - Database-dependant migration operations

SYNOPSIS

  my $object = DBIx::Migration::Directories->new(
    $dbh => $some_database_handle, schema => "foo"
  );

  if($object->db->table_exists("foo")) {
    print "Table foo exists.\n";
  }

DESCRIPTION

DBIx::Migration::Directories::Database contains any migration operations that actually make use of a database. The purpose of having these as a separate module is to make it possible to override specific SQL operations for specific database engines do things in a non-standard way (eg; MySQL).

CONSTRUCTOR

new(%args)

Creates a new DBIx::Migration::Directories::Base object. %args is a hash of properties to set on the object; the following properties are used by DBIx::Migration::Directories::Base:

dbh

Required. The DBIx::Transaction database handle to use for queries. This handle should already be connected to the database that you wish to manage.

driver

The name of the DBD driver we are using. You normally don't want to specify this option; DBIx::Migration::Directories::Database will automatically pull the driver name out of the database handle you pass along.

METHODS

db_schemas

Queries the migration schema, and returns a hash reference containing all of the schemas currently registered in this database. The keys in this hash are the schemas' names, and the values are hash references, containing the contents of that schema's row in the database as key/value pairs:

name

The schema's name, again.

version

The current version of this schema.

db_get_current_version($schema)

Looks at DBIx::Migration::Directories's tables to see what the specified schema's version is. If the schema is installed, the current version will be returned, otherwise this method will return undef.

db_schema_version_log($schema)

Queries the migration schema, and returns an array reference containing the specified schema's version history. The "$schema" parameter is required.

Each entry in the array reference returned is a hash reference, containing the contents of that schema's log rows in the database as key/value pairs:

id

A unique integer identifier for this log entry.

schema_name

Schema this log entry refers to.

event_time

Time this migration action took place.

old_version

Schema version before this migration action took place.

new_version

Schema version after this migration took place.

db_delete_schema_record($schema)

Remove any knowledge about the specified schema from the migration log. It probably isn't safe to call it on it's own unless you are sure your schema is gone.

table_exists($table)

Queries the database and returns 1 if the named table exists, 0 otherwise.

sql_insert_migration_schema_version($schema, $version)

Returns an SQL query used to add a new schema to the database.

sql_update_migration_schema_version($schema, $version)

Returns an SQL query used to change the version number we have on record for a schema.

sql_insert_migration_schema_log($schema, $from, $to)

Returns an SQL query used to add a new schema log record to the database indicating a migration between schema versions.

sql_table_exists($table)

Returns a string containing an SQL query that is garunteed to only return rows if the named table exists. Base.pm's implementation queries the SQL standard INFORMATION_SCHEMA table.

AUTHOR

Tyler "Crackerjack" MacDonald <japh@crackerjack.net>

LICENSE

Copyright 2009 Tyler "Crackerjack" MacDonald <japh@crackerjack.net>

This is free software; You may distribute it under the same terms as perl itself.

SEE ALSO

DBIx::Migration::Directories::Database::mysql, DBIx::Migration::Directories::Database::SQLite2