PostgreSQL¶
PostgreSQL Data Types and Custom SQL Constructs¶
As with all SQLAlchemy dialects, all UPPERCASE types that are known to be
valid with PostgreSQL are importable from the top level dialect, whether
they originate from sqlalchemy.types or from the local dialect:
from sqlalchemy.dialects.postgresql import (
ARRAY,
BIGINT,
BIT,
BOOLEAN,
BYTEA,
CHAR,
CIDR,
DATE,
DOUBLE_PRECISION,
ENUM,
FLOAT,
HSTORE,
INET,
INTEGER,
INTERVAL,
JSON,
JSONB,
MACADDR,
MONEY,
NUMERIC,
OID,
REAL,
SMALLINT,
TEXT,
TIME,
TIMESTAMP,
UUID,
VARCHAR,
INT4RANGE,
INT8RANGE,
NUMRANGE,
DATERANGE,
TSRANGE,
TSTZRANGE,
TSVECTOR,
)Types which are specific to PostgreSQL, or have PostgreSQL-specific construction arguments, are as follows:
Range Types¶
The new range column types found in PostgreSQL 9.2 onwards are catered for by the following types:
The types above get most of their functionality from the following mixin:
Warning
The range type DDL support should work with any PostgreSQL DBAPI
driver, however the data types returned may vary. If you are using
psycopg2, it’s recommended to upgrade to version 2.5 or later
before using these column types.
When instantiating models that use these column types, you should pass
whatever data type is expected by the DBAPI driver you’re using for
the column type. For psycopg2 these are
psycopg2.extras.NumericRange,
psycopg2.extras.DateRange,
psycopg2.extras.DateTimeRange and
psycopg2.extras.DateTimeTZRange or the class you’ve
registered with psycopg2.extras.register_range.
For example:
from psycopg2.extras import DateTimeRange
from sqlalchemy.dialects.postgresql import TSRANGE
class RoomBooking(Base):
__tablename__ = 'room_booking'
room = Column(Integer(), primary_key=True)
during = Column(TSRANGE())
booking = RoomBooking(
room=101,
during=DateTimeRange(datetime(2013, 3, 23), None)
)PostgreSQL Constraint Types¶
SQLAlchemy supports PostgreSQL EXCLUDE constraints via the
ExcludeConstraint class:
For example:
from sqlalchemy.dialects.postgresql import ExcludeConstraint, TSRANGE
class RoomBooking(Base):
__tablename__ = "room_booking"
room = Column(Integer(), primary_key=True)
during = Column(TSRANGE())
__table_args__ = (ExcludeConstraint(("room", "="), ("during", "&&")),)