From c1e5ca8be42131b9f4d3d9cc58f5ce2532650cd9 Mon Sep 17 00:00:00 2001
From: Mauricio Giacomini Girardello <mgg12@inf.ufpr.br>
Date: Thu, 12 May 2016 11:56:54 -0300
Subject: [PATCH] adding papertrail migrations
---
...140322_ensure_versions_table_is_deleted.rb | 6 ++
db/migrate/20160512143532_create_versions.rb | 68 +++++++++++++++++++
2 files changed, 74 insertions(+)
create mode 100644 db/migrate/20160512140322_ensure_versions_table_is_deleted.rb
create mode 100644 db/migrate/20160512143532_create_versions.rb
diff --git a/db/migrate/20160512140322_ensure_versions_table_is_deleted.rb b/db/migrate/20160512140322_ensure_versions_table_is_deleted.rb
new file mode 100644
index 00000000..d79b2e5a
--- /dev/null
+++ b/db/migrate/20160512140322_ensure_versions_table_is_deleted.rb
@@ -0,0 +1,6 @@
+class EnsureVersionsTableIsDeleted < ActiveRecord::Migration
+ def change
+ table = :versions
+ drop_table table if table_exists? table
+ end
+end
diff --git a/db/migrate/20160512143532_create_versions.rb b/db/migrate/20160512143532_create_versions.rb
new file mode 100644
index 00000000..dbe8ec81
--- /dev/null
+++ b/db/migrate/20160512143532_create_versions.rb
@@ -0,0 +1,68 @@
+# This migration creates the `versions` table, the only schema PT requires.
+# All other migrations PT provides are optional.
+class CreateVersions < ActiveRecord::Migration
+ # Class names of MySQL adapters.
+ # - `MysqlAdapter` - Used by gems: `mysql`, `activerecord-jdbcmysql-adapter`.
+ # - `Mysql2Adapter` - Used by `mysql2` gem.
+ MYSQL_ADAPTERS = [
+ "ActiveRecord::ConnectionAdapters::MysqlAdapter",
+ "ActiveRecord::ConnectionAdapters::Mysql2Adapter"
+ ].freeze
+
+ # The largest text column available in all supported RDBMS is
+ # 1024^3 - 1 bytes, roughly one gibibyte. We specify a size
+ # so that MySQL will use `longtext` instead of `text`. Otherwise,
+ # when serializing very large objects, `text` might not be big enough.
+ TEXT_BYTES = 1_073_741_823
+
+ def change
+ create_table :versions, versions_table_options do |t|
+ t.string :item_type, null: false
+ t.integer :item_id, null: false
+ t.string :event, null: false
+ t.string :whodunnit
+ t.text :object, limit: TEXT_BYTES
+
+ # Known issue in MySQL: fractional second precision
+ # -------------------------------------------------
+ #
+ # MySQL timestamp columns do not support fractional seconds unless
+ # defined with "fractional seconds precision". MySQL users should manually
+ # add fractional seconds precision to this migration, specifically, to
+ # the `created_at` column.
+ # (https://dev.mysql.com/doc/refman/5.6/en/fractional-seconds.html)
+ #
+ # MySQL users should also upgrade to rails 4.2, which is the first
+ # version of ActiveRecord with support for fractional seconds in MySQL.
+ # (https://github.com/rails/rails/pull/14359)
+ #
+ t.datetime :created_at
+ end
+ add_index :versions, [:item_type, :item_id]
+ end
+
+ private
+
+ # Even modern versions of MySQL still use `latin1` as the default character
+ # encoding. Many users are not aware of this, and run into trouble when they
+ # try to use PaperTrail in apps that otherwise tend to use UTF-8. Postgres, by
+ # comparison, uses UTF-8 except in the unusual case where the OS is configured
+ # with a custom locale.
+ #
+ # - https://dev.mysql.com/doc/refman/5.7/en/charset-applications.html
+ # - http://www.postgresql.org/docs/9.4/static/multibyte.html
+ #
+ # Furthermore, MySQL's original implementation of UTF-8 was flawed, and had
+ # to be fixed later by introducing a new charset, `utf8mb4`.
+ #
+ # - https://mathiasbynens.be/notes/mysql-utf8mb4
+ # - https://dev.mysql.com/doc/refman/5.5/en/charset-unicode-utf8mb4.html
+ #
+ def versions_table_options
+ if MYSQL_ADAPTERS.include?(connection.class.name)
+ { options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci" }
+ else
+ {}
+ end
+ end
+end
--
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