Peewee

* Fix bug in new `_pk` / `get_id()` implementation for models that explicitly
have disabled a primary-key.

[View commits](https://github.com/coleifer/peewee/compare/3.11.0...3.11.1)

* Fixes 1991. This particular issue involves joining 3 models together in a
chain, where the outer two models are empty. Previously peewee would make the
middle model an empty model instance (since a link might be needed from the
source model to the outermost model). But since both were empty, it is more
correct to make the intervening model a NULL value on the foreign-key field
rather than an empty instance.
* An unrelated fix came out of the work on 1991 where hashing a model whose
primary-key happened to be a foreign-key could trigger the FK resolution
query. This patch fixes the `Model._pk` and `get_id()` interfaces so they
no longer introduce the possibility of accidentally resolving the FK.
* Allow `Field.contains()`, `startswith()` and `endswith()` to compare against
another column-like object or expression.
* Workaround for MySQL prior to 8 and MariaDB handling of union queries inside
of parenthesized expressions (like IN).
* Be more permissive in letting invalid values be stored in a field whose type
is INTEGER or REAL, since Sqlite allows this.
* `TimestampField` resolution cleanup. Now values 0 *and* 1 will resolve to a
timestamp resolution of 1 second. Values 2-6 specify the number of decimal
places (hundredths to microsecond), or alternatively the resolution can still
be provided as a power of 10, e.g. 10, 1000 (millisecond), 1e6 (microsecond).
* When self-referential foreign-keys are inherited, the foreign-key on the
subclass will also be self-referential (rather than pointing to the parent
model).
* Add TSV import/export option to the `dataset` extension.
* Add item interface to the `dataset.Table` class for doing primary-key lookup,
assignment, or deletion.
* Extend the mysql `ReconnectMixin` helper to work with mysql-connector.
* Fix mapping of double-precision float in postgres schema reflection.
Previously it mapped to single-precision, now it correctly uses a double.
* Fix issue where `PostgresqlExtDatabase` and `MySQLConnectorDatabase` did not
respect the `autoconnect` setting.

[View commits](https://github.com/coleifer/peewee/compare/3.10.0...3.11.0)

* Add a helper to `playhouse.mysql_ext` for creating `Match` full-text search
expressions.
* Added date-part properties to `TimestampField` for accessing the year, month,
day, etc., within a SQL expression.
* Added `to_timestamp()` helper for `DateField` and `DateTimeField` that
produces an expression returning a unix timestamp.
* Add `autoconnect` parameter to `Database` classes. This parameter defaults to
`True` and is compatible with previous versions of Peewee, in which executing
a query on a closed database would open a connection automatically. To make
it easier to catch inconsistent use of the database connection, this behavior
can now be disabled by specifying `autoconnect=False`, making an explicit
call to `Database.connect()` needed before executing a query.
* Added database-agnostic interface for obtaining a random value.
* Allow `isolation_level` to be specified when initializing a Postgres db.
* Allow hybrid properties to be used on model aliases. Refs 1969.
* Support aggregates with FILTER predicates on the latest Sqlite.

Changes

* More aggressively slot row values into the appropriate field when building
objects from the database cursor (rather than using whatever
`cursor.description` tells us, which is buggy in older Sqlite).
* Be more permissive in what we accept in the `insert_many()` and `insert()`
methods.
* When implicitly joining a model with multiple foreign-keys, choose the
foreign-key whose name matches that of the related model. Previously, this
would have raised a `ValueError` stating that multiple FKs existed.
* Improved date truncation logic for Sqlite and MySQL to make more compatible
with Postgres' `date_trunc()` behavior. Previously, truncating a datetime to
month resolution would return `'2019-08'` for example. As of 3.10.0, the
Sqlite and MySQL `date_trunc` implementation returns a full datetime, e.g.
`'2019-08-01 00:00:00'`.
* Apply slightly different logic for casting JSON values with Postgres.
Previously, Peewee just wrapped the value in the psycopg2 `Json()` helper.
In this version, Peewee now dumps the json to a string and applies an
explicit cast to the underlying JSON data-type (e.g. json or jsonb).

Bug fixes

* Save hooks can now be called for models without a primary key.
* Fixed bug in the conversion of Python values to JSON when using Postgres.
* Fix for differentiating empty values from NULL values in `model_to_dict`.
* Fixed a bug referencing primary-key values that required some kind of
conversion (e.g., a UUID). See 1979 for details.
* Add small jitter to the pool connection timestamp to avoid issues when
multiple connections are checked-out at the same exact time.

[View commits](https://github.com/coleifer/peewee/compare/3.9.6...3.10.0)

* Support nesting the `Database` instance as a context-manager. The outermost
block will handle opening and closing the connection along with wrapping
everything in a transaction. Nested blocks will use savepoints.
* Add new `session_start()`, `session_commit()` and `session_rollback()`
interfaces to the Database object to support using transactional controls in
situations where a context-manager or decorator is awkward.
* Fix error that would arise when attempting to do an empty bulk-insert.
* Set `isolation_level=None` in SQLite connection constructor rather than
afterwards using the setter.
* Add `create_table()` method to `Select` query to implement `CREATE TABLE AS`.
* Cleanup some declarations in the Sqlite C extension.
* Add new example showing how to implement Reddit's ranking algorithm in SQL.

[View commits](https://github.com/coleifer/peewee/compare/3.9.5...3.9.6)

* Added small helper for setting timezone when using Postgres.
* Improved SQL generation for `VALUES` clause.
* Support passing resolution to `TimestampField` as a power-of-10.
* Small improvements to `INSERT` queries when the primary-key is not an
auto-incrementing integer, but is generated by the database server (eg uuid).
* Cleanups to virtual table implementation and python-to-sqlite value
conversions.
* Fixed bug related to binding previously-unbound models to a database using a
context manager, 1913.

[View commits](https://github.com/coleifer/peewee/compare/3.9.4...3.9.5)

* Add `Model.bulk_update()` method for bulk-updating fields across multiple
model instances. [Docs](http://docs.peewee-orm.com/en/latest/peewee/api.html#Model.bulk_update).
* Add `lazy_load` parameter to `ForeignKeyField`. When initialized with
`lazy_load=False`, the foreign-key will not use an additional query to
resolve the related model instance. Instead, if the related model instance is
not available, the underlying FK column value is returned (behaving like the
"_id" descriptor).
* Added `Model.truncate_table()` method.
* The `reflection` and `pwiz` extensions now attempt to be smarter about
converting database table and column names into snake-case. To disable this,
you can set `snake_case=False` when calling the `Introspector.introspect()`
method or use the `-L` (legacy naming) option with the `pwiz` script.
* Bulk insert via ``insert_many()`` no longer require specification of the
fields argument when the inserted rows are lists/tuples. In that case, the
fields will be inferred to be all model fields except any auto-increment id.
* Add `DatabaseProxy`, which implements several of the `Database` class context
managers. This allows you to reference some of the special features of the
database object without directly needing to initialize the proxy first.
* Add support for window function frame exclusion and added built-in support
for the GROUPS frame type.
* Add support for chaining window functions by extending a previously-declared
window function.
* Playhouse Postgresql extension `TSVectorField.match()` method supports an
additional argument `plain`, which can be used to control the parsing of the
TS query.
* Added very minimal `JSONField` to the playhouse MySQL extension.

[View commits](https://github.com/coleifer/peewee/compare/3.9.3...3.9.4)