Class array

lib/sqlalchemy/dialects/postgresql/array.py:76–235

A PostgreSQL ARRAY literal. This is used to produce ARRAY literals in SQL expressions, e.g.:: from sqlalchemy.dialects.postgresql import array from sqlalchemy.dialects import postgresql from sqlalchemy import select, func stmt = select(array([1, 2]) + array([3,

class array(expression.ExpressionClauseList[_T]):
    """A PostgreSQL ARRAY literal.

    This is used to produce ARRAY literals in SQL expressions, e.g.::

        from sqlalchemy.dialects.postgresql import array
        from sqlalchemy.dialects import postgresql
        from sqlalchemy import select, func

        stmt = select(array([1, 2]) + array([3, 4, 5]))

        print(stmt.compile(dialect=postgresql.dialect()))

    Produces the SQL:

    .. sourcecode:: sql

        SELECT ARRAY[%(param_1)s, %(param_2)s] ||
            ARRAY[%(param_3)s, %(param_4)s, %(param_5)s]) AS anon_1

    An instance of :class:`.array` will always have the datatype
    :class:`_types.ARRAY`.  The "inner" type of the array is inferred from the
    values present, unless the :paramref:`_postgresql.array.type_` keyword
    argument is passed::

        array(["foo", "bar"], type_=CHAR)

    When constructing an empty array, the :paramref:`_postgresql.array.type_`
    argument is particularly important as PostgreSQL server typically requires
    a cast to be rendered for the inner type in order to render an empty array.
    SQLAlchemy's compilation for the empty array will produce this cast so
    that::

        stmt = array([], type_=Integer)
        print(stmt.compile(dialect=postgresql.dialect()))

    Produces:

    .. sourcecode:: sql

        ARRAY[]::INTEGER[]

    As required by PostgreSQL for empty arrays.

    .. versionadded:: 2.0.40 added support to render empty PostgreSQL array
       literals with a required cast.

    Multidimensional arrays are produced by nesting :class:`.array` constructs.
    The dimensionality of the final :class:`_types.ARRAY`
    type is calculated by
    recursively adding the dimensions of the inner :class:`_types.ARRAY`
    type::

        stmt = select(
            array(
                [array([1, 2]), array([3, 4]), array([column("q"), column("x")])]
            )
        )