PostgreSQL — SQLAlchemy 2.0.0b1 documentation

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', '&&')),
    )