Provided by: libdbix-class-deploymenthandler-perl_0.002222-1_all bug

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 schemata  as well as 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 spiritually
       based upon DBIx::Migration::Directories, but has a lot of 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
        |- _source
        |  |- deploy
        |     |- 1
        |     |  `- 001-auto.yml
        |     |- 2
        |     |  `- 001-auto.yml
        |     `- 3
        |        `- 001-auto.yml
        |- SQLite
        |  |- downgrade
        |  |  `- 2-1
        |  |     `- 001-auto.sql
        |  |- deploy
        |  |  `- 1
        |  |     `- 001-auto.sql
        |  `- upgrade
        |     |- 1-2
        |     |  `- 001-auto.sql
        |     `- 2-3
        |        `- 001-auto.sql
        |- _common
        |  |- downgrade
        |  |  `- 2-1
        |  |     `- 002-remove-customers.pl
        |  `- upgrade
        |     `- 1-2
        |     |  `- 002-generate-customers.pl
        |     `- _any
        |        `- 999-bump-action.pl
        `- MySQL
           |- downgrade
           |  `- 2-1
           |     `- 001-auto.sql
           |- initialize
           |  `- 1
           |     |- 001-create_database.pl
           |     `- 002-create_users_and_permissions.pl
           |- deploy
           |  `- 1
           |     `- 001-auto.sql
           `- upgrade
              `- 1-2
                 `- 001-auto.sql

       So basically, the code

        $dm->deploy(1)

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

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

       would run "$sql_migration_dir/SQLite/upgrade/1-2/001-auto.sql" followed by
       "$sql_migration_dir/_common/upgrade/1-2/002-generate-customers.pl", and finally punctuated
       by "$sql_migration_dir/_common/upgrade/_any/999-bump-action.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 database independent.

       Note that unlike most steps in the process, "initialize" will not run SQL, as there may
       not even be an database at initialize 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 initialize is to have it prompt for
       username and password, and then call the appropriate "CREATE DATABASE" commands etc.

   Directory Specification
       The following subdirectories are recognized by this DeployMethod:

       "_source"
         This directory can contain the following directories:

         "deploy"
           This directory merely contains directories named after schema versions, which in turn
           contain "yaml" files that are serialized versions of the schema at that version.
           These files are not for editing by hand.

       "_preprocess_schema"
         This directory can contain the following directories:

         "downgrade"
           This directory merely contains directories named after migrations, which are of the
           form "$from_version-$to_version".  Inside of these directories you may put Perl
           scripts which are to return a subref that takes the arguments "$from_schema,
           $to_schema", which are SQL::Translator::Schema objects.

         "upgrade"
           This directory merely contains directories named after migrations, which are of the
           form "$from_version-$to_version".  Inside of these directories you may put Perl
           scripts which are to return a subref that takes the arguments "$from_schema,
           $to_schema", which are SQL::Translator::Schema objects.

         A typical usage of "_preprocess_schema" is to define indices or other non-DBIC type
         metadata.  Here is an example of how one might do that:

         The following coderef could be placed in a file called
         _preprocess_schema/1-2/001-add-user-index.pl

          sub {
             my ($from, $to) = @_;

             $to->get_table('Users')->add_index(
                name => 'idx_Users_name',
                fields => ['name'],
             )
          }

         This would ensure that in version 2 of the schema the generated migrations include an
         index on "Users.name".  Frustratingly, due to the nature of SQL::Translator, you'll need
         to add this to each migration or it will detect that it was left out and kindly remove
         the index for you.

         An alternative to the above, which is likely to be a lot less annoying, is to define
         such data in your schema directly, and only change it as you need to:

          package MyApp::Schema::Result::User;

          #[...]

          sub sqlt_deploy_hook ( $self, $sqlt_table ) {
             $sqlt_table->add_index(name => 'idx_Users_name', fields => [ 'name' ]);
          }

       $storage_type
         This is a set of scripts that gets run depending on what your storage type is.  If you
         are not sure what your storage type is, take a look at the producers listed for
         SQL::Translator.  Also note, "_common" is a special case.  "_common" will get merged
         into whatever other files you already have.  This directory can contain the following
         directories itself:

         "initialize"
           If you are using the "initialize" functionality, you should call initialize() before
           calling "install". This has the same structure as the "deploy" subdirectory as well;
           that is, it has a directory for each schema version.  Unlike "deploy", "upgrade", and
           "downgrade" though, it can only run ".pl" files, and the coderef in the perl files get
           no arguments passed to them.

         "deploy"
           Gets run when the schema is "deploy"ed.  Structure is a directory per schema version,
           and then files are merged with "_common" and run in filename order.  ".sql" files are
           merely run, as expected.  ".pl" files are run according to "PERL SCRIPTS".

         "upgrade"
           Gets run when the schema is "upgrade"d.  Structure is a directory per upgrade step,
           (for example, "1-2" for upgrading from version 1 to version 2,) and then files are
           merged with "_common" and run in filename order.  ".sql" files are merely run, as
           expected.  ".pl" files are run according to "PERL SCRIPTS".

         "downgrade"
           Gets run when the schema is "downgrade"d.  Structure is a directory per downgrade
           step, (for example, "2-1" for downgrading from version 2 to version 1,) and then files
           are merged with "_common" and run in filename order.  ".sql" files are merely run, as
           expected.  ".pl" files are run according to "PERL SCRIPTS".

       Note that there can be an "_any" in the place of any of the versions (like "1-2" or 1),
       which means those scripts will be run every time.  So if you have an "_any" in
       "_common/upgrade", that script will get run for every upgrade.

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 and the version set as it's arguments.

       A very basic perl script might look like:

        #!perl

        use strict;
        use warnings;

        use DBIx::Class::DeploymentHandler::DeployMethod::SQL::Translator::ScriptHelpers
           'schema_from_schema_loader';

        schema_from_schema_loader({ naming => 'v4' }, sub {
          my $schema = shift;

          # [1] for deploy, [1,2] for upgrade or downgrade, probably used with _any
          my $versions = shift;

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

       Note that the above uses "schema_from_schema_loader" in
       DBIx::Class::DeploymentHandler::DeployMethod::SQL::Translator::ScriptHelpers.  Using a raw
       coderef is strongly discouraged as it is likely to break as you modify your schema.

SEE ALSO

       This class is an implementation of DBIx::Class::DeploymentHandler::HandlesDeploy.  Pretty
       much all the documentation is there.

ATTRIBUTES

   ignore_ddl
       This attribute will, when set to true (default is false), cause the DM to use
       SQL::Translator to use the "_source"'s serialized SQL::Translator::Schema instead of any
       pregenerated SQL.  If you have a development server this is probably the best plan of
       action as you will not be putting as many generated files in your version control.  Goes
       well with with "databases" of "[]".

   force_overwrite
       When this attribute is true generated files will be overwritten when the methods which
       create such files are run again.  The default is false, in which case the program will die
       with a message saying which file needs to be deleted.

   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".

   version_source
       The source name used to register the version storage with "schema".  Defaults to
       "__VERSION".

AUTHOR

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

COPYRIGHT AND LICENSE

       This software is copyright (c) 2018 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.

perl v5.26.1                   DBIx::Class::DeploymentHandler::DeployMethod::SQL::Translator(3pm)