---
name: "DBIx::Class::Schema::Loader::Manual::UpgradingFromV4"
section: "3pm"
platform: "linux"
package: "libdbix-class-schema-loader-perl"
version: "0.07053-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/DBIx::Class::Schema::Loader::Manual::UpgradingFromV4"
---

# DBIx::Class::Schema::Loader::Manual::UpgradingFromV4(3pm)

Important Information Related to Upgrading from Version 0.04006

## NAME

DBIx::Class::Schema::Loader::Manual::UpgradingFromV4 - Important Information Related to Upgrading from Version 0.04006

## What Changed

- •

  add\_column

  The new Loader detects much more information about columns and sets flags like `"is_auto_increment"` that it didn't set before.

- •

  RelBuilder

  The new RelBuilder will give you nicer accessor names for relationships, so you will no longer have conflicts between a foreign key column and the relationship accessor itself (if the FK is named `"_id"`.)

  It will also more correctly infer the relationship type, e.g. some relationships that were previously detected as a `"has_many"` will now be a `"might_have"` (when it detects a unique constraint on the foreign key column.)

  Also `"cascade_delete"` and `"cascade_copy"` are turned off for by default for `"has_many"` and `"might_have"` relationships, while `"belongs_to"` relationships are created with `"on_delete => 'CASCADE'"` and `"on_update => 'CASCADE'"` by default. This is overridable via relationship\_attrs.

- •

  moniker\_map

  Table names are now singularized when determining the `"Result"` class names. So the table `"user_roles"` would have become `"UserRoles"` in `0.04006` but now becomes `"UserRole"` instead.

- •

  use\_namespaces

  Now defaults to on. See "use\_namespaces" in DBIx::Class::Schema::Loader::Base and "load\_namespaces" in DBIx::Class::Schema.

- •

  Support for more databases

  We now support Microsoft SQL Server and Sybase, and there are also many improvements to the other backends.

## Backward Compatibility

In backward compatibility mode, the Loader will use the old relationship names and types, will not singularize monikers for tables, and `"use_namespaces"` will be off.

To control this behavior see "naming" in DBIx::Class::Schema::Loader::Base and "use\_namespaces" in DBIx::Class::Schema::Loader::Base.

### Static Schemas

When reading a `"Schema.pm"` from a static schema generated with an `0.04` version of Loader, backward compatibility mode will default to on, unless overridden with the `"naming"` and/or `"use_namespaces"` attributes.

### Dynamic Schemas

Dynamic schemas will always by default use `0.04006` mode and have `"use_namespaces"` off.

To upgrade a dynamic schema, set the `"naming"` and `"use_namespaces"` attributes (which is proxied to the loader) in your `"Schema.pm"`:

```
    __PACKAGE__->naming('current');
    __PACKAGE__->use_namespaces(1);
```

## AUTHORS

See "AUTHORS" in DBIx::Class::Schema::Loader.

## LICENSE

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