``__repr__()``, particularly with regards to the MySQL integer/numeric/
character types which feature a wide variety of keyword arguments.
The ``__repr__()`` is important for use with Alembic autogenerate
for when Python code is rendered in a migration script.
[ticket:2893]

- move out tests, dialect specific out of compiler, compiler tests use new API,
legacy API tests in test_selecatble
- add support for adaptation of ForUpdateArg, alias support in compilers

Python ``Decimal`` via string is now configurable.  The
flag ``decimal_return_scale`` is now supported by all :class:`.Numeric`
and :class:`.Float` types, which will ensure this many digits are taken
from the native floating point value when it is converted to string.
If not present, the type will make use of the value of ``.scale``, if
the type supports this setting and it is non-None.  Otherwise the original
default length of 10 is used. [ticket:2867]

this complements the work in :ticket:`2183` where we begin to support
reflection of foreign key options such as ON UPDATE/ON DELETE
cascade. [ticket:2839]

of :class:`.ForeignKeyConstraint` is silently ignored on the MySQL
backend, will be reverted as of 0.9; this keyword will now render again, raising
errors on MySQL as it is not understood - the same behavior will also
apply to the ``initially`` keyword.  In 0.8, the keywords will remain
ignored but a warning is emitted.   Additionally, the ``match`` keyword
now raises a :class:`.CompileError` on 0.9 and emits a warning on 0.8;
this keyword is not only silently ignored by MySQL but also breaks
the ON UPDATE/ON DELETE options.

To use a :class:`.ForeignKeyConstraint`
that does not render or renders differently on MySQL, use a custom
compilation option.  An example of this usage has been added to the
documentation, see :ref:`mysql_foreign_keys`.
[ticket:2721] [ticket:2839]

behavior as that of :class:`.mysql.ENUM`.  Quotes are not required when
setting up the value, but quotes that are present will be auto-detected
along with a warning.  This also helps with Alembic where
the SET type doesn't render with quotes. [ticket:2817]

query string to override those defaults set up in the connect,
including "buffered" and "raise_on_warnings".
[ticket:2515]

mssql to ensure that any literal SQL expression values are
rendered directly as literals, instead of as bound parameters,
within a CREATE INDEX statement. [ticket:2742]
- don't need expression_as_ddl(); literal_binds and include_table
take care of this functionality.