through all possible set values
assume that the empty string, or a set with a single empty string value, is in fact a set with a single empty string; instead, this is by default treated as the empty set. In order to handle persistence of a :class:`.mysql.SET` that actually wants to include the blank value ``''`` as a legitimate value, a new bitwise operational mode is added which is enabled by the :paramref:`.mysql.SET.retrieve_as_bitwise` flag, which will persist and retrieve values unambiguously using their bitflag positioning. Storage and retrieval of unicode values for driver configurations that aren't converting unicode natively is also repaired. fixes #3283
sort_tables_and_constraints function. - The DDL generation system of :meth:`.MetaData.create_all` and :meth:`.Metadata.drop_all` has been enhanced to in most cases automatically handle the case of mutually dependent foreign key constraints; the need for the :paramref:`.ForeignKeyConstraint.use_alter` flag is greatly reduced. The system also works for constraints which aren't given a name up front; only in the case of DROP is a name required for at least one of the constraints involved in the cycle. fixes #3282
return type is not strictly assumed to be boolean; it now returns a :class:`.Boolean` subclass called :class:`.MatchType`. The type will still produce boolean behavior when used in Python expressions, however the dialect can override its behavior at result time. In the case of MySQL, while the MATCH operator is typically used in a boolean context within an expression, if one actually queries for the value of a match expression, a floating point value is returned; this value is not compatible with SQLAlchemy's C-based boolean processor, so MySQL's result-set behavior now follows that of the :class:`.Float` type. A new operator object ``notmatch_op`` is also added to better allow dialects to define the negation of a match operation. fixes #3263
- add a test for PG reflection of unique index without any unique constraint - for PG, don't include 'duplicates_constraint' in the entry if the index does not actually mirror a constraint - use a distinct method for unique constraint reflection within table - catch unique constraint not implemented condition; this may be within some dialects and also is expected to be supported by Alembic tests - migration + changelogs for #3184 - add individual doc notes as well to MySQL, Postgreql fixes #3184
Calls to reflect a table did not create any UniqueConstraint objects. The reflection core made no calls to get_unique_constraints and as a result, the sqlite dialect would never reflect any unique constraints. MySQL transparently converts unique constraints into unique indexes, but SQLAlchemy would reflect those as an Index object and as a UniqueConstraint. The reflection core will now deduplicate the unique constraints. PostgreSQL would reflect unique constraints as an Index object and as a UniqueConstraint object. The reflection core will now deduplicate the unique indexes.