Lowercase raw SQL has been replaced by 07b659ca already. This commit
replaces everything else of raw SQL.

Added by 101c19f5.

The same is not true of `define_attribute`, which is meant to be the low
level no-magic API that sits underneath. The differences between the two
APIs are:

- `attribute`
  - Lazy (the attribute will be defined after the schema has loaded)
  - Allows either a type object or a symbol
- `define_attribute`
  - Runs immediately (might get trampled by schema loading)
  - Requires a type object

This was the last blocker in terms of public interface requirements
originally discussed for this feature back in May. All the
implementation blockers have been cleared, so this feature is probably
ready for release (pending one more look-over by me).

a column type `xml` is missing in regexp pattarn. However,
`assert_equal 1, lengths.uniq.length` is success when `lengths` are all
`nil` because a column type is missing. a test will be failed by using
`compact` when a column type is missing.

`.` is regexp meta character. It should be escape for `assert_match`
correctly.

Technically changes the API, as it will allow any object which responds
to `===`. Personally, I think this is more flexible.

Dump the standard schema once instead of redoing it per test

Allows :limit defaults to be changed without pulling the rug out from
under old migrations that omitted :limit because it matched the default
at the time.

Since 'drop table if exists' statement does not always work with
some databases such as Oracle.

respect `table_name_prefix` and `table_name_suffix`.

The only type that has a scale is decimal. There's a special case where
decimal columns with 0 scale are type cast to integers if the scale is
not specified. Appears to only affect schema dumping.

citext makes it possible to use AR Hash finders for case-insensitive matching as sql UPPER/LOWER functions are not needed.

Fixes: #11524

We can conditional define the tests depending on the adapter or
connection.

Lets keep the skip for fail tests that need to be fixed.

This is causing every default value in PostreSQL database to being
handled as default function.

Fixes #12581