304 lines
9.7 KiB
Python
304 lines
9.7 KiB
Python
# postgresql/array.py
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# Copyright (C) 2005-2018 the SQLAlchemy authors and contributors
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# <see AUTHORS file>
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#
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# This module is part of SQLAlchemy and is released under
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# the MIT License: http://www.opensource.org/licenses/mit-license.php
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from .base import ischema_names, colspecs
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from ...sql import expression, operators
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from ...sql.base import SchemaEventTarget
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from ... import types as sqltypes
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try:
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from uuid import UUID as _python_UUID
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except ImportError:
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_python_UUID = None
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def Any(other, arrexpr, operator=operators.eq):
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"""A synonym for the :meth:`.ARRAY.Comparator.any` method.
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This method is legacy and is here for backwards-compatibility.
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.. seealso::
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:func:`.expression.any_`
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"""
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return arrexpr.any(other, operator)
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def All(other, arrexpr, operator=operators.eq):
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"""A synonym for the :meth:`.ARRAY.Comparator.all` method.
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This method is legacy and is here for backwards-compatibility.
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.. seealso::
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:func:`.expression.all_`
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"""
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return arrexpr.all(other, operator)
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class array(expression.Tuple):
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"""A PostgreSQL ARRAY literal.
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This is used to produce ARRAY literals in SQL expressions, e.g.::
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from sqlalchemy.dialects.postgresql import array
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from sqlalchemy.dialects import postgresql
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from sqlalchemy import select, func
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stmt = select([
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array([1,2]) + array([3,4,5])
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])
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print stmt.compile(dialect=postgresql.dialect())
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Produces the SQL::
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SELECT ARRAY[%(param_1)s, %(param_2)s] ||
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ARRAY[%(param_3)s, %(param_4)s, %(param_5)s]) AS anon_1
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An instance of :class:`.array` will always have the datatype
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:class:`.ARRAY`. The "inner" type of the array is inferred from
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the values present, unless the ``type_`` keyword argument is passed::
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array(['foo', 'bar'], type_=CHAR)
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.. versionadded:: 0.8 Added the :class:`~.postgresql.array` literal type.
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See also:
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:class:`.postgresql.ARRAY`
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"""
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__visit_name__ = 'array'
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def __init__(self, clauses, **kw):
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super(array, self).__init__(*clauses, **kw)
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self.type = ARRAY(self.type)
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def _bind_param(self, operator, obj, _assume_scalar=False, type_=None):
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if _assume_scalar or operator is operators.getitem:
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# if getitem->slice were called, Indexable produces
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# a Slice object from that
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assert isinstance(obj, int)
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return expression.BindParameter(
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None, obj, _compared_to_operator=operator,
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type_=type_,
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_compared_to_type=self.type, unique=True)
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else:
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return array([
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self._bind_param(operator, o, _assume_scalar=True, type_=type_)
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for o in obj])
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def self_group(self, against=None):
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if (against in (
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operators.any_op, operators.all_op, operators.getitem)):
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return expression.Grouping(self)
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else:
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return self
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CONTAINS = operators.custom_op("@>", precedence=5)
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CONTAINED_BY = operators.custom_op("<@", precedence=5)
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OVERLAP = operators.custom_op("&&", precedence=5)
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class ARRAY(sqltypes.ARRAY):
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"""PostgreSQL ARRAY type.
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.. versionchanged:: 1.1 The :class:`.postgresql.ARRAY` type is now
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a subclass of the core :class:`.types.ARRAY` type.
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The :class:`.postgresql.ARRAY` type is constructed in the same way
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as the core :class:`.types.ARRAY` type; a member type is required, and a
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number of dimensions is recommended if the type is to be used for more
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than one dimension::
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from sqlalchemy.dialects import postgresql
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mytable = Table("mytable", metadata,
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Column("data", postgresql.ARRAY(Integer, dimensions=2))
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)
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The :class:`.postgresql.ARRAY` type provides all operations defined on the
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core :class:`.types.ARRAY` type, including support for "dimensions", indexed
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access, and simple matching such as :meth:`.types.ARRAY.Comparator.any`
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and :meth:`.types.ARRAY.Comparator.all`. :class:`.postgresql.ARRAY` class also
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provides PostgreSQL-specific methods for containment operations, including
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:meth:`.postgresql.ARRAY.Comparator.contains`
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:meth:`.postgresql.ARRAY.Comparator.contained_by`,
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and :meth:`.postgresql.ARRAY.Comparator.overlap`, e.g.::
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mytable.c.data.contains([1, 2])
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The :class:`.postgresql.ARRAY` type may not be supported on all
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PostgreSQL DBAPIs; it is currently known to work on psycopg2 only.
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Additionally, the :class:`.postgresql.ARRAY` type does not work directly in
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conjunction with the :class:`.ENUM` type. For a workaround, see the
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special type at :ref:`postgresql_array_of_enum`.
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.. seealso::
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:class:`.types.ARRAY` - base array type
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:class:`.postgresql.array` - produces a literal array value.
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"""
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class Comparator(sqltypes.ARRAY.Comparator):
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"""Define comparison operations for :class:`.ARRAY`.
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Note that these operations are in addition to those provided
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by the base :class:`.types.ARRAY.Comparator` class, including
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:meth:`.types.ARRAY.Comparator.any` and
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:meth:`.types.ARRAY.Comparator.all`.
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"""
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def contains(self, other, **kwargs):
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"""Boolean expression. Test if elements are a superset of the
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elements of the argument array expression.
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"""
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return self.operate(CONTAINS, other, result_type=sqltypes.Boolean)
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def contained_by(self, other):
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"""Boolean expression. Test if elements are a proper subset of the
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elements of the argument array expression.
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"""
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return self.operate(
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CONTAINED_BY, other, result_type=sqltypes.Boolean)
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def overlap(self, other):
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"""Boolean expression. Test if array has elements in common with
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an argument array expression.
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"""
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return self.operate(OVERLAP, other, result_type=sqltypes.Boolean)
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comparator_factory = Comparator
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def __init__(self, item_type, as_tuple=False, dimensions=None,
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zero_indexes=False):
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"""Construct an ARRAY.
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E.g.::
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Column('myarray', ARRAY(Integer))
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Arguments are:
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:param item_type: The data type of items of this array. Note that
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dimensionality is irrelevant here, so multi-dimensional arrays like
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``INTEGER[][]``, are constructed as ``ARRAY(Integer)``, not as
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``ARRAY(ARRAY(Integer))`` or such.
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:param as_tuple=False: Specify whether return results
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should be converted to tuples from lists. DBAPIs such
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as psycopg2 return lists by default. When tuples are
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returned, the results are hashable.
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:param dimensions: if non-None, the ARRAY will assume a fixed
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number of dimensions. This will cause the DDL emitted for this
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ARRAY to include the exact number of bracket clauses ``[]``,
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and will also optimize the performance of the type overall.
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Note that PG arrays are always implicitly "non-dimensioned",
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meaning they can store any number of dimensions no matter how
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they were declared.
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:param zero_indexes=False: when True, index values will be converted
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between Python zero-based and PostgreSQL one-based indexes, e.g.
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a value of one will be added to all index values before passing
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to the database.
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.. versionadded:: 0.9.5
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"""
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if isinstance(item_type, ARRAY):
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raise ValueError("Do not nest ARRAY types; ARRAY(basetype) "
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"handles multi-dimensional arrays of basetype")
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if isinstance(item_type, type):
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item_type = item_type()
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self.item_type = item_type
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self.as_tuple = as_tuple
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self.dimensions = dimensions
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self.zero_indexes = zero_indexes
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@property
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def hashable(self):
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return self.as_tuple
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@property
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def python_type(self):
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return list
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def compare_values(self, x, y):
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return x == y
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def _proc_array(self, arr, itemproc, dim, collection):
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if dim is None:
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arr = list(arr)
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if dim == 1 or dim is None and (
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# this has to be (list, tuple), or at least
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# not hasattr('__iter__'), since Py3K strings
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# etc. have __iter__
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not arr or not isinstance(arr[0], (list, tuple))):
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if itemproc:
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return collection(itemproc(x) for x in arr)
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else:
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return collection(arr)
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else:
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return collection(
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self._proc_array(
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x, itemproc,
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dim - 1 if dim is not None else None,
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collection)
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for x in arr
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)
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def bind_processor(self, dialect):
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item_proc = self.item_type.dialect_impl(dialect).\
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bind_processor(dialect)
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def process(value):
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if value is None:
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return value
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else:
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return self._proc_array(
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value,
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item_proc,
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self.dimensions,
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list)
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return process
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def result_processor(self, dialect, coltype):
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item_proc = self.item_type.dialect_impl(dialect).\
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result_processor(dialect, coltype)
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def process(value):
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if value is None:
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return value
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else:
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return self._proc_array(
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value,
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item_proc,
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self.dimensions,
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tuple if self.as_tuple else list)
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return process
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colspecs[sqltypes.ARRAY] = ARRAY
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ischema_names['_array'] = ARRAY
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