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rails--rails/activerecord/lib/active_record/schema.rb
eileencodes 7cc27d749c Move SchemaMigration to migration_context
This PR moves the `schema_migration` to `migration_context` so that we
can access the `schema_migration` per connection.

This does not change behavior of the SchemaMigration if you are using
one database. This also does not change behavior of any public APIs.
`Migrator` is private as is `MigrationContext` so we can change these as
needed.

We now need to pass a `schema_migration` to `Migrator` so that we can
run migrations on the right connection outside the context of a rake
task.

The bugs this fixes were discovered while debugging the issues around
the SchemaCache on initialization with multiple database. It was clear
that `get_all_versions` wouldn't work without these changes outside the
context of a rake task (because in the rake task we establish a
connection and change AR::Base.connection to the db we're running on).

Because the `SchemaCache` relies on the `SchemaMigration` information we
need to make sure we store it per-connection rather than on
ActiveRecord::Base.

[Eileen M. Uchitelle & Aaron Patterson]
2019-06-14 11:15:08 -04:00

61 lines
2 KiB
Ruby

# frozen_string_literal: true
module ActiveRecord
# = Active Record \Schema
#
# Allows programmers to programmatically define a schema in a portable
# DSL. This means you can define tables, indexes, etc. without using SQL
# directly, so your applications can more easily support multiple
# databases.
#
# Usage:
#
# ActiveRecord::Schema.define do
# create_table :authors do |t|
# t.string :name, null: false
# end
#
# add_index :authors, :name, :unique
#
# create_table :posts do |t|
# t.integer :author_id, null: false
# t.string :subject
# t.text :body
# t.boolean :private, default: false
# end
#
# add_index :posts, :author_id
# end
#
# ActiveRecord::Schema is only supported by database adapters that also
# support migrations, the two features being very similar.
class Schema < Migration::Current
# Eval the given block. All methods available to the current connection
# adapter are available within the block, so you can easily use the
# database definition DSL to build up your schema (
# {create_table}[rdoc-ref:ConnectionAdapters::SchemaStatements#create_table],
# {add_index}[rdoc-ref:ConnectionAdapters::SchemaStatements#add_index], etc.).
#
# The +info+ hash is optional, and if given is used to define metadata
# about the current schema (currently, only the schema's version):
#
# ActiveRecord::Schema.define(version: 2038_01_19_000001) do
# ...
# end
def self.define(info = {}, &block)
new.define(info, &block)
end
def define(info, &block) # :nodoc:
instance_eval(&block)
if info[:version].present?
connection.schema_migration.create_table
connection.assume_migrated_upto_version(info[:version])
end
ActiveRecord::InternalMetadata.create_table
ActiveRecord::InternalMetadata[:environment] = connection.migration_context.current_environment
end
end
end