Module « sqlalchemy »

Classe « ARRAY »

Informations générales

Héritage

builtins.object
    Traversible
        TypeEngine
    builtins.object
        Concatenable
    builtins.object
        Indexable
    builtins.object
        SchemaEventTarget
            ARRAY

Définition

class ARRAY(SchemaEventTarget, Indexable, Concatenable, TypeEngine):

Description _{[extrait de ARRAY.__doc__]}

Represent a SQL Array type.

    .. note::  This type serves as the basis for all ARRAY operations.
       However, currently **only the PostgreSQL backend has support for SQL
       arrays in SQLAlchemy**. It is recommended to use the PostgreSQL-specific
       :class:`sqlalchemy.dialects.postgresql.ARRAY` type directly when using
       ARRAY types with PostgreSQL, as it provides additional operators
       specific to that backend.

    :class:`_types.ARRAY` is part of the Core in support of various SQL
    standard functions such as :class:`_functions.array_agg`
    which explicitly involve
    arrays; however, with the exception of the PostgreSQL backend and possibly
    some third-party dialects, no other SQLAlchemy built-in dialect has support
    for this type.

    An :class:`_types.ARRAY` type is constructed given the "type"
    of element::

        mytable = Table("mytable", metadata,
                Column("data", ARRAY(Integer))
            )

    The above type represents an N-dimensional array,
    meaning a supporting backend such as PostgreSQL will interpret values
    with any number of dimensions automatically.   To produce an INSERT
    construct that passes in a 1-dimensional array of integers::

        connection.execute(
                mytable.insert(),
                data=[1,2,3]
        )

    The :class:`_types.ARRAY` type can be constructed given a fixed number
    of dimensions::

        mytable = Table("mytable", metadata,
                Column("data", ARRAY(Integer, dimensions=2))
            )

    Sending a number of dimensions is optional, but recommended if the
    datatype is to represent arrays of more than one dimension.  This number
    is used:

    * When emitting the type declaration itself to the database, e.g.
      ``INTEGER[][]``

    * When translating Python values to database values, and vice versa, e.g.
      an ARRAY of :class:`.Unicode` objects uses this number to efficiently
      access the string values inside of array structures without resorting
      to per-row type inspection

    * When used with the Python ``getitem`` accessor, the number of dimensions
      serves to define the kind of type that the ``[]`` operator should
      return, e.g. for an ARRAY of INTEGER with two dimensions::

          >>> expr = table.c.column[5]  # returns ARRAY(Integer, dimensions=1)
          >>> expr = expr[6]  # returns Integer

    For 1-dimensional arrays, an :class:`_types.ARRAY` instance with no
    dimension parameter will generally assume single-dimensional behaviors.

    SQL expressions of type :class:`_types.ARRAY` have support for "index" and
    "slice" behavior.  The Python ``[]`` operator works normally here, given
    integer indexes or slices.  Arrays default to 1-based indexing.
    The operator produces binary expression
    constructs which will produce the appropriate SQL, both for
    SELECT statements::

        select(mytable.c.data[5], mytable.c.data[2:7])

    as well as UPDATE statements when the :meth:`_expression.Update.values`
    method
    is used::

        mytable.update().values({
            mytable.c.data[5]: 7,
            mytable.c.data[2:7]: [1, 2, 3]
        })

    The :class:`_types.ARRAY` type also provides for the operators
    :meth:`.types.ARRAY.Comparator.any` and
    :meth:`.types.ARRAY.Comparator.all`. The PostgreSQL-specific version of
    :class:`_types.ARRAY` also provides additional operators.

    .. versionadded:: 1.1.0

    .. seealso::

        :class:`sqlalchemy.dialects.postgresql.ARRAY`

    

Constructeur(s)

Signature du constructeur	Description
__init__(self, item_type, as_tuple=False, dimensions=None, zero_indexes=False)	Construct an :class:`_types.ARRAY`. [extrait de __init__.__doc__]

Attributs statiques hérités de la classe TypeEngine

hashable

Liste des opérateurs

Opérateurs hérités de la classe object

__eq__, __ge__, __gt__, __le__, __lt__, __ne__

Méthodes héritées de la classe TypeEngine

__init_subclass__, __repr__, __str__, __subclasshook__, adapt, as_generic, bind_expression, bind_processor, coerce_compared_value, column_expression, compare_against_backend, compile, copy, copy_value, dialect_impl, evaluates_none, get_dbapi_type, literal_processor, result_processor, with_variant

Méthodes héritées de la classe Traversible

__class_getitem__, get_children

Méthodes héritées de la classe object

__delattr__, __dir__, __format__, __getattribute__, __hash__, __reduce__, __reduce_ex__, __setattr__, __sizeof__