/ 
DBIx-Class-DeploymentHandler-0.001000_11
River stage two • 12 direct dependents • 12 total dependents
/ DBIx::Class::DeploymentHandler::DeployMethod::SQL::Translator

NAME

DBIx::Class::DeploymentHandler::DeployMethod::SQL::Translator - Manage your SQL and Perl migrations in nicely laid out directories

DESCRIPTION

This class is the meat of DBIx::Class::DeploymentHandler. It takes care of generating serialized sql files representing schemata as well as serialized sql files to move from one version of a schema to the rest. One of the hallmark features of this class is that it allows for multiple sql files for deploy and upgrade, allowing developers to fine tune deployment. In addition it also allows for perl files to be run at any stage of the process.

For basic usage see DBIx::Class::DeploymentHandler::HandlesDeploy. What's documented here is extra fun stuff or private methods.

DIRECTORY LAYOUT

Arguably this is the best feature of DBIx::Class::DeploymentHandler. It's heavily based upon DBIx::Migration::Directories, but has some extensions and modifications, so even if you are familiar with it, please read this. I feel like the best way to describe the layout is with the following example:

$sql_migration_dir
|- SQLite
|  |- down
|  |  `- 2-1
|  |     `- 001-auto.sql-json
|  |- schema
|  |  `- 1
|  |     `- 001-auto.sql-json
|  `- up
|     |- 1-2
|     |  `- 001-auto.sql-json
|     `- 2-3
|        `- 001-auto.sql-json
|- _common
|  |- down
|  |  `- 2-1
|  |     `- 002-remove-customers.pl
|  `- up
|     `- 1-2
|        `- 002-generate-customers.pl
|- _generic
|  |- down
|  |  `- 2-1
|  |     `- 001-auto.sql-json
|  |- schema
|  |  `- 1
|  |     `- 001-auto.sql-json
|  `- up
|     `- 1-2
|        |- 001-auto.sql-json
|        `- 002-create-stored-procedures.sql
`- MySQL
   |- down
   |  `- 2-1
   |     `- 001-auto.sql-json
   |- preinstall
   |  `- 1
   |     |- 001-create_database.pl
   |     `- 002-create_users_and_permissions.pl
   |- schema
   |  `- 1
   |     `- 001-auto.sql-json
   `- up
      `- 1-2
         `- 001-auto.sql-json

So basically, the code

$dm->deploy(1)

on an SQLite database that would simply run $sql_migration_dir/SQLite/schema/1/001-auto.sql-json. Next,

$dm->upgrade_single_step([1,2])

would run $sql_migration_dir/SQLite/up/1-2/001-auto.sql-json followed by $sql_migration_dir/_common/up/1-2/002-generate-customers.pl.

.pl files don't have to be in the _common directory, but most of the time they should be, because perl scripts are generally be database independent.

_generic exists for when you for some reason are sure that your SQL is generic enough to run on all databases. Good luck with that one.

Note that unlike most steps in the process, preinstall will not run SQL, as there may not even be an database at preinstall time. It will run perl scripts just like the other steps in the process, but nothing is passed to them. Until people have used this more it will remain freeform, but a recommended use of preinstall is to have it prompt for username and password, and then call the appropriate CREATE DATABASE commands etc.

SERIALIZED SQL

The SQL that this module generates and uses is serialized into an array of SQL statements. The reason being that some databases handle multiple statements in a single execution differently. Generally you do not need to worry about this as these are scripts generated for you. If you find that you are editing them on a regular basis something is wrong and you either need to submit a bug or consider writing extra serialized SQL or Perl scripts to run before or after the automatically generated script.

NOTE: Currently the SQL is serialized into JSON. I am willing to merge in patches that will allow more serialization formats if you want that feature, but if you do send me a patch for that realize that I do not want to add YAML support or whatever, I would rather add a generic method of adding any serialization format.

PERL SCRIPTS

A perl script for this tool is very simple. It merely needs to contain an anonymous sub that takes a DBIx::Class::Schema as it's only argument. A very basic perl script might look like:

#!perl

use strict;
use warnings;

sub {
  my $schema = shift;

  $schema->resultset('Users')->create({
    name => 'root',
    password => 'root',
  })
}

ATTRIBUTES

schema

The DBIx::Class::Schema (required) that is used to talk to the database and generate the DDL.

storage

The DBIx::Class::Storage that is actually used to talk to the database and generate the DDL. This is automatically created with "_build_storage".

sql_translator_args

The arguments that get passed to SQL::Translator when it's used.

script_directory

The directory (default 'sql') that scripts are stored in

databases

The types of databases (default [qw( MySQL SQLite PostgreSQL )]) to generate files for

txn_wrap

Set to true (which is the default) to wrap all upgrades and deploys in a single transaction.

schema_version

The version the schema on your harddrive is at. Defaults to $self->schema->schema_version.

AUTHOR

Arthur Axel "fREW" Schmidt <frioux+cpan@gmail.com>

COPYRIGHT AND LICENSE

This software is copyright (c) 2010 by Arthur Axel "fREW" Schmidt.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.