This option was added in b9fa3541. But it does not seem to work.

Use `SchemaMigration.all_versions` instead of
`SchemaMigration.all.map(&:version)` to avoid to instantiate AR objects.

Simply use `SchemaMigration.table_name` instead.

Related #25174.

`db:schema:load` doesn't work with subdirectories like previous
`db:migrate:status`. `Migrator.migration_files` should be used in
`assume_migrated_upto_version` to fix the issue.

Follow up of #26266.

The default type of `primary_key` and `references` were changed to
`bigint` since #26266. But `create_join_table` column type is still
`integer`. It should respect `references` column type.

The native timestamp type in MySQL is different from datetime type.
Internal representation of the timestamp type is UNIX time, This means
that timestamp columns are affected by time zone.

```
> SET time_zone = '+00:00';
Query OK, 0 rows affected (0.00 sec)

> INSERT INTO time_with_zone(ts,dt) VALUES (NOW(),NOW());
Query OK, 1 row affected (0.02 sec)

> SELECT * FROM time_with_zone;
+---------------------+---------------------+
| ts                  | dt                  |
+---------------------+---------------------+
| 2016-02-07 22:11:44 | 2016-02-07 22:11:44 |
+---------------------+---------------------+
1 row in set (0.00 sec)

> SET time_zone = '-08:00';
Query OK, 0 rows affected (0.00 sec)

> SELECT * FROM time_with_zone;
+---------------------+---------------------+
| ts                  | dt                  |
+---------------------+---------------------+
| 2016-02-07 14:11:44 | 2016-02-07 22:11:44 |
+---------------------+---------------------+
1 row in set (0.00 sec)
```

Extra `data_source_exists?(table_name)` is unneeded if
`drop_table(table_name, if_exists: true)` directly.

The `default` arg of `index_name_exists?` is only used the adapter does
not implemented `indexes`. But currently all adapters implemented
`indexes` (See #26688). Therefore the `default` arg is never used.

Closes #27979

Column options are passed as an hash args then used as `options` hash in
`add_column_options!`. Converting args to attributes is inconvinient for
using options as an hash.

Follow up to #26266.

The default type of `primary_key` and `references` were changed to
`bigint` since #26266. But legacy migration and sqlite3 adapter should
keep its previous behavior.

`ColumnDumper#migration_keys` was extracted to customize keys for
standardized column arguments widths. But the feature was removed in
df84e986. The internal method is no longer used for that.

These internal initialize methods are no longer used internally.

This reverts commit 39c77eb1, reversing
changes made to 9f6f51be.

Remove `initialize_schema_migrations_table` and `initialize_internal_metadata_table` internal public methods

These internal methods accidentally appeared in the doc, and so almost
useless. It is enough to create these internal tables directly, and
indeed do so in several places.

https://github.com/rails/rails/blob/v5.0.1/activerecord/lib/active_record/schema.rb#L55
https://github.com/rails/rails/blob/v5.0.1/activerecord/lib/active_record/railties/databases.rake#L6
https://github.com/rails/rails/blob/v5.0.1/activerecord/lib/active_record/tasks/database_tasks.rb#L230

Passing `name` to `tables` is already deprecated at #21601.
Passing `name` to `indexes` is also unused.

Some methods were added to public API in
5b14129d and they should be not part of
the public API.

Fixes #26635, #26641.

SQLite's default query interface ignores anything after the first
semicolon in a query. This is actually quite common behavior in database
drivers, especially when dealing with code paths for prepared statements
(which we are). While this should only affect SQLite, as I'm not aware
of any drivers which don't support multi-insert. Even if this does
affect other third party drivers though, I'd prefer not to assume that
more than one query can be executed per call to `execute`.

Fixes #26948.
Close #27242.

Follow up to 99cf7558.

`migration_keys` includes `name` but `name` is not a column option.

```ruby
  # Before
  t.index ["firm_id", "type", "rating"], name: "company_index", order: {"rating"=>:desc}, using: :btree

  # After
  t.index ["firm_id", "type", "rating"], name: "company_index", order: { rating: :desc }, using: :btree
```

Currently blank comment does not dump to `db/schema.rb`. But created it
even if specified blank.

Currently all adapters (postgresql, mysql2, sqlite3, oracle-enhanced,
and sqlserver) implemented `indexes` and schema dumper expects
implemented `indexes`.

https://github.com/rails/rails/blob/v5.0.0/activerecord/lib/active_record/schema_dumper.rb#L208

Therefore `respond_to?(:indexes)` checking is unnecessary.

Currently does not work the following code.

```ruby
  add_index(:people, ["last_name", "first_name"], order: { last_name: :desc, first_name: :asc })
```

Normalize column names and options to fix the issue.