1033 lines
34 KiB
Python
1033 lines
34 KiB
Python
# engine/result.py
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# Copyright (C) 2005-2014 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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"""Define result set constructs including :class:`.ResultProxy`
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and :class:`.RowProxy."""
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from .. import exc, util
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from ..sql import expression, sqltypes
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import collections
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import operator
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# This reconstructor is necessary so that pickles with the C extension or
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# without use the same Binary format.
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try:
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# We need a different reconstructor on the C extension so that we can
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# add extra checks that fields have correctly been initialized by
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# __setstate__.
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from sqlalchemy.cresultproxy import safe_rowproxy_reconstructor
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# The extra function embedding is needed so that the
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# reconstructor function has the same signature whether or not
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# the extension is present.
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def rowproxy_reconstructor(cls, state):
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return safe_rowproxy_reconstructor(cls, state)
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except ImportError:
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def rowproxy_reconstructor(cls, state):
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obj = cls.__new__(cls)
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obj.__setstate__(state)
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return obj
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try:
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from sqlalchemy.cresultproxy import BaseRowProxy
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except ImportError:
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class BaseRowProxy(object):
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__slots__ = ('_parent', '_row', '_processors', '_keymap')
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def __init__(self, parent, row, processors, keymap):
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"""RowProxy objects are constructed by ResultProxy objects."""
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self._parent = parent
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self._row = row
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self._processors = processors
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self._keymap = keymap
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def __reduce__(self):
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return (rowproxy_reconstructor,
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(self.__class__, self.__getstate__()))
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def values(self):
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"""Return the values represented by this RowProxy as a list."""
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return list(self)
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def __iter__(self):
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for processor, value in zip(self._processors, self._row):
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if processor is None:
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yield value
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else:
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yield processor(value)
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def __len__(self):
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return len(self._row)
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def __getitem__(self, key):
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try:
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processor, obj, index = self._keymap[key]
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except KeyError:
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processor, obj, index = self._parent._key_fallback(key)
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except TypeError:
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if isinstance(key, slice):
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l = []
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for processor, value in zip(self._processors[key],
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self._row[key]):
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if processor is None:
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l.append(value)
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else:
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l.append(processor(value))
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return tuple(l)
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else:
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raise
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if index is None:
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raise exc.InvalidRequestError(
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"Ambiguous column name '%s' in result set! "
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"try 'use_labels' option on select statement." % key)
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if processor is not None:
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return processor(self._row[index])
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else:
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return self._row[index]
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def __getattr__(self, name):
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try:
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return self[name]
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except KeyError as e:
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raise AttributeError(e.args[0])
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class RowProxy(BaseRowProxy):
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"""Proxy values from a single cursor row.
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Mostly follows "ordered dictionary" behavior, mapping result
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values to the string-based column name, the integer position of
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the result in the row, as well as Column instances which can be
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mapped to the original Columns that produced this result set (for
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results that correspond to constructed SQL expressions).
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"""
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__slots__ = ()
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def __contains__(self, key):
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return self._parent._has_key(self._row, key)
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def __getstate__(self):
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return {
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'_parent': self._parent,
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'_row': tuple(self)
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}
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def __setstate__(self, state):
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self._parent = parent = state['_parent']
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self._row = state['_row']
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self._processors = parent._processors
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self._keymap = parent._keymap
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__hash__ = None
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def _op(self, other, op):
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return op(tuple(self), tuple(other)) \
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if isinstance(other, RowProxy) \
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else op(tuple(self), other)
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def __lt__(self, other):
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return self._op(other, operator.lt)
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def __le__(self, other):
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return self._op(other, operator.le)
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def __ge__(self, other):
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return self._op(other, operator.ge)
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def __gt__(self, other):
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return self._op(other, operator.gt)
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def __eq__(self, other):
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return self._op(other, operator.eq)
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def __ne__(self, other):
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return self._op(other, operator.ne)
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def __repr__(self):
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return repr(tuple(self))
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def has_key(self, key):
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"""Return True if this RowProxy contains the given key."""
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return self._parent._has_key(self._row, key)
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def items(self):
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"""Return a list of tuples, each tuple containing a key/value pair."""
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# TODO: no coverage here
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return [(key, self[key]) for key in self.keys()]
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def keys(self):
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"""Return the list of keys as strings represented by this RowProxy."""
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return self._parent.keys
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def iterkeys(self):
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return iter(self._parent.keys)
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def itervalues(self):
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return iter(self)
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try:
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# Register RowProxy with Sequence,
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# so sequence protocol is implemented
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from collections import Sequence
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Sequence.register(RowProxy)
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except ImportError:
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pass
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class ResultMetaData(object):
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"""Handle cursor.description, applying additional info from an execution
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context."""
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def __init__(self, parent, metadata):
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self._processors = processors = []
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# We do not strictly need to store the processor in the key mapping,
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# though it is faster in the Python version (probably because of the
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# saved attribute lookup self._processors)
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self._keymap = keymap = {}
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self.keys = []
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context = parent.context
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dialect = context.dialect
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typemap = dialect.dbapi_type_map
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translate_colname = context._translate_colname
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self.case_sensitive = dialect.case_sensitive
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# high precedence key values.
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primary_keymap = {}
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for i, rec in enumerate(metadata):
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colname = rec[0]
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coltype = rec[1]
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if dialect.description_encoding:
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colname = dialect._description_decoder(colname)
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if translate_colname:
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colname, untranslated = translate_colname(colname)
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if dialect.requires_name_normalize:
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colname = dialect.normalize_name(colname)
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if context.result_map:
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try:
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name, obj, type_ = context.result_map[
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colname if self.case_sensitive else colname.lower()]
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except KeyError:
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name, obj, type_ = \
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colname, None, typemap.get(coltype, sqltypes.NULLTYPE)
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else:
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name, obj, type_ = \
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colname, None, typemap.get(coltype, sqltypes.NULLTYPE)
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processor = context.get_result_processor(type_, colname, coltype)
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processors.append(processor)
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rec = (processor, obj, i)
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# indexes as keys. This is only needed for the Python version of
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# RowProxy (the C version uses a faster path for integer indexes).
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primary_keymap[i] = rec
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# populate primary keymap, looking for conflicts.
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if primary_keymap.setdefault(
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name if self.case_sensitive
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else name.lower(),
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rec) is not rec:
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# place a record that doesn't have the "index" - this
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# is interpreted later as an AmbiguousColumnError,
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# but only when actually accessed. Columns
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# colliding by name is not a problem if those names
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# aren't used; integer access is always
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# unambiguous.
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primary_keymap[name
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if self.case_sensitive
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else name.lower()] = rec = (None, obj, None)
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self.keys.append(colname)
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if obj:
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for o in obj:
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keymap[o] = rec
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# technically we should be doing this but we
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# are saving on callcounts by not doing so.
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# if keymap.setdefault(o, rec) is not rec:
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# keymap[o] = (None, obj, None)
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if translate_colname and \
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untranslated:
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keymap[untranslated] = rec
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# overwrite keymap values with those of the
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# high precedence keymap.
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keymap.update(primary_keymap)
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if parent._echo:
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context.engine.logger.debug(
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"Col %r", tuple(x[0] for x in metadata))
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@util.pending_deprecation("0.8", "sqlite dialect uses "
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"_translate_colname() now")
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def _set_keymap_synonym(self, name, origname):
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"""Set a synonym for the given name.
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Some dialects (SQLite at the moment) may use this to
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adjust the column names that are significant within a
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row.
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"""
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rec = (processor, obj, i) = self._keymap[origname if
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self.case_sensitive
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else origname.lower()]
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if self._keymap.setdefault(name, rec) is not rec:
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self._keymap[name] = (processor, obj, None)
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def _key_fallback(self, key, raiseerr=True):
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map = self._keymap
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result = None
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if isinstance(key, util.string_types):
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result = map.get(key if self.case_sensitive else key.lower())
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# fallback for targeting a ColumnElement to a textual expression
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# this is a rare use case which only occurs when matching text()
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# or colummn('name') constructs to ColumnElements, or after a
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# pickle/unpickle roundtrip
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elif isinstance(key, expression.ColumnElement):
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if key._label and (
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key._label
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if self.case_sensitive
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else key._label.lower()) in map:
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result = map[key._label
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if self.case_sensitive
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else key._label.lower()]
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elif hasattr(key, 'name') and (
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key.name
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if self.case_sensitive
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else key.name.lower()) in map:
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# match is only on name.
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result = map[key.name
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if self.case_sensitive
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else key.name.lower()]
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# search extra hard to make sure this
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# isn't a column/label name overlap.
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# this check isn't currently available if the row
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# was unpickled.
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if result is not None and \
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result[1] is not None:
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for obj in result[1]:
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if key._compare_name_for_result(obj):
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break
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else:
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result = None
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if result is None:
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if raiseerr:
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raise exc.NoSuchColumnError(
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"Could not locate column in row for column '%s'" %
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expression._string_or_unprintable(key))
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else:
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return None
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else:
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map[key] = result
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return result
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def _has_key(self, row, key):
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if key in self._keymap:
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return True
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else:
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return self._key_fallback(key, False) is not None
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def __getstate__(self):
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return {
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'_pickled_keymap': dict(
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(key, index)
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for key, (processor, obj, index) in self._keymap.items()
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if isinstance(key, util.string_types + util.int_types)
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),
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'keys': self.keys,
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"case_sensitive": self.case_sensitive,
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}
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def __setstate__(self, state):
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# the row has been processed at pickling time so we don't need any
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# processor anymore
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self._processors = [None for _ in range(len(state['keys']))]
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self._keymap = keymap = {}
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for key, index in state['_pickled_keymap'].items():
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# not preserving "obj" here, unfortunately our
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# proxy comparison fails with the unpickle
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keymap[key] = (None, None, index)
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self.keys = state['keys']
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self.case_sensitive = state['case_sensitive']
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self._echo = False
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class ResultProxy(object):
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"""Wraps a DB-API cursor object to provide easier access to row columns.
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Individual columns may be accessed by their integer position,
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case-insensitive column name, or by ``schema.Column``
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object. e.g.::
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row = fetchone()
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col1 = row[0] # access via integer position
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col2 = row['col2'] # access via name
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col3 = row[mytable.c.mycol] # access via Column object.
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``ResultProxy`` also handles post-processing of result column
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data using ``TypeEngine`` objects, which are referenced from
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the originating SQL statement that produced this result set.
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"""
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_process_row = RowProxy
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out_parameters = None
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_can_close_connection = False
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_metadata = None
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def __init__(self, context):
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self.context = context
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self.dialect = context.dialect
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self.closed = False
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self.cursor = self._saved_cursor = context.cursor
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self.connection = context.root_connection
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self._echo = self.connection._echo and \
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context.engine._should_log_debug()
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self._init_metadata()
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def _init_metadata(self):
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metadata = self._cursor_description()
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if metadata is not None:
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self._metadata = ResultMetaData(self, metadata)
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def keys(self):
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"""Return the current set of string keys for rows."""
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if self._metadata:
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return self._metadata.keys
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else:
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return []
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@util.memoized_property
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def rowcount(self):
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"""Return the 'rowcount' for this result.
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The 'rowcount' reports the number of rows *matched*
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by the WHERE criterion of an UPDATE or DELETE statement.
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.. note::
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Notes regarding :attr:`.ResultProxy.rowcount`:
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* This attribute returns the number of rows *matched*,
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which is not necessarily the same as the number of rows
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that were actually *modified* - an UPDATE statement, for example,
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may have no net change on a given row if the SET values
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given are the same as those present in the row already.
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Such a row would be matched but not modified.
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On backends that feature both styles, such as MySQL,
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rowcount is configured by default to return the match
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count in all cases.
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* :attr:`.ResultProxy.rowcount` is *only* useful in conjunction
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with an UPDATE or DELETE statement. Contrary to what the Python
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DBAPI says, it does *not* return the
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number of rows available from the results of a SELECT statement
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as DBAPIs cannot support this functionality when rows are
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unbuffered.
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* :attr:`.ResultProxy.rowcount` may not be fully implemented by
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all dialects. In particular, most DBAPIs do not support an
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aggregate rowcount result from an executemany call.
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The :meth:`.ResultProxy.supports_sane_rowcount` and
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:meth:`.ResultProxy.supports_sane_multi_rowcount` methods
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will report from the dialect if each usage is known to be
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supported.
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* Statements that use RETURNING may not return a correct
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rowcount.
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"""
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try:
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return self.context.rowcount
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except Exception as e:
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self.connection._handle_dbapi_exception(
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e, None, None, self.cursor, self.context)
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@property
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def lastrowid(self):
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"""return the 'lastrowid' accessor on the DBAPI cursor.
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This is a DBAPI specific method and is only functional
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for those backends which support it, for statements
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where it is appropriate. It's behavior is not
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consistent across backends.
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Usage of this method is normally unnecessary when
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using insert() expression constructs; the
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:attr:`~ResultProxy.inserted_primary_key` attribute provides a
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tuple of primary key values for a newly inserted row,
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regardless of database backend.
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"""
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try:
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return self._saved_cursor.lastrowid
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except Exception as e:
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self.connection._handle_dbapi_exception(
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e, None, None,
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self._saved_cursor, self.context)
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@property
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def returns_rows(self):
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"""True if this :class:`.ResultProxy` returns rows.
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I.e. if it is legal to call the methods
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:meth:`~.ResultProxy.fetchone`,
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:meth:`~.ResultProxy.fetchmany`
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:meth:`~.ResultProxy.fetchall`.
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"""
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return self._metadata is not None
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|
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@property
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def is_insert(self):
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"""True if this :class:`.ResultProxy` is the result
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of a executing an expression language compiled
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:func:`.expression.insert` construct.
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When True, this implies that the
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:attr:`inserted_primary_key` attribute is accessible,
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assuming the statement did not include
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a user defined "returning" construct.
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"""
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return self.context.isinsert
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|
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def _cursor_description(self):
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"""May be overridden by subclasses."""
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return self._saved_cursor.description
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def close(self, _autoclose_connection=True):
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"""Close this ResultProxy.
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|
Closes the underlying DBAPI cursor corresponding to the execution.
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Note that any data cached within this ResultProxy is still available.
|
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For some types of results, this may include buffered rows.
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If this ResultProxy was generated from an implicit execution,
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the underlying Connection will also be closed (returns the
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underlying DBAPI connection to the connection pool.)
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This method is called automatically when:
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* all result rows are exhausted using the fetchXXX() methods.
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* cursor.description is None.
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"""
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if not self.closed:
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self.closed = True
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self.connection._safe_close_cursor(self.cursor)
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if _autoclose_connection and \
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self.connection.should_close_with_result:
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self.connection.close()
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# allow consistent errors
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self.cursor = None
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|
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def __iter__(self):
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while True:
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row = self.fetchone()
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if row is None:
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raise StopIteration
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else:
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yield row
|
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|
|
@util.memoized_property
|
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def inserted_primary_key(self):
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"""Return the primary key for the row just inserted.
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|
|
The return value is a list of scalar values
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corresponding to the list of primary key columns
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in the target table.
|
|
|
|
This only applies to single row :func:`.insert`
|
|
constructs which did not explicitly specify
|
|
:meth:`.Insert.returning`.
|
|
|
|
Note that primary key columns which specify a
|
|
server_default clause,
|
|
or otherwise do not qualify as "autoincrement"
|
|
columns (see the notes at :class:`.Column`), and were
|
|
generated using the database-side default, will
|
|
appear in this list as ``None`` unless the backend
|
|
supports "returning" and the insert statement executed
|
|
with the "implicit returning" enabled.
|
|
|
|
Raises :class:`~sqlalchemy.exc.InvalidRequestError` if the executed
|
|
statement is not a compiled expression construct
|
|
or is not an insert() construct.
|
|
|
|
"""
|
|
|
|
if not self.context.compiled:
|
|
raise exc.InvalidRequestError(
|
|
"Statement is not a compiled "
|
|
"expression construct.")
|
|
elif not self.context.isinsert:
|
|
raise exc.InvalidRequestError(
|
|
"Statement is not an insert() "
|
|
"expression construct.")
|
|
elif self.context._is_explicit_returning:
|
|
raise exc.InvalidRequestError(
|
|
"Can't call inserted_primary_key "
|
|
"when returning() "
|
|
"is used.")
|
|
|
|
return self.context.inserted_primary_key
|
|
|
|
def last_updated_params(self):
|
|
"""Return the collection of updated parameters from this
|
|
execution.
|
|
|
|
Raises :class:`~sqlalchemy.exc.InvalidRequestError` if the executed
|
|
statement is not a compiled expression construct
|
|
or is not an update() construct.
|
|
|
|
"""
|
|
if not self.context.compiled:
|
|
raise exc.InvalidRequestError(
|
|
"Statement is not a compiled "
|
|
"expression construct.")
|
|
elif not self.context.isupdate:
|
|
raise exc.InvalidRequestError(
|
|
"Statement is not an update() "
|
|
"expression construct.")
|
|
elif self.context.executemany:
|
|
return self.context.compiled_parameters
|
|
else:
|
|
return self.context.compiled_parameters[0]
|
|
|
|
def last_inserted_params(self):
|
|
"""Return the collection of inserted parameters from this
|
|
execution.
|
|
|
|
Raises :class:`~sqlalchemy.exc.InvalidRequestError` if the executed
|
|
statement is not a compiled expression construct
|
|
or is not an insert() construct.
|
|
|
|
"""
|
|
if not self.context.compiled:
|
|
raise exc.InvalidRequestError(
|
|
"Statement is not a compiled "
|
|
"expression construct.")
|
|
elif not self.context.isinsert:
|
|
raise exc.InvalidRequestError(
|
|
"Statement is not an insert() "
|
|
"expression construct.")
|
|
elif self.context.executemany:
|
|
return self.context.compiled_parameters
|
|
else:
|
|
return self.context.compiled_parameters[0]
|
|
|
|
@property
|
|
def returned_defaults(self):
|
|
"""Return the values of default columns that were fetched using
|
|
the :meth:`.ValuesBase.return_defaults` feature.
|
|
|
|
The value is an instance of :class:`.RowProxy`, or ``None``
|
|
if :meth:`.ValuesBase.return_defaults` was not used or if the
|
|
backend does not support RETURNING.
|
|
|
|
.. versionadded:: 0.9.0
|
|
|
|
.. seealso::
|
|
|
|
:meth:`.ValuesBase.return_defaults`
|
|
|
|
"""
|
|
return self.context.returned_defaults
|
|
|
|
def lastrow_has_defaults(self):
|
|
"""Return ``lastrow_has_defaults()`` from the underlying
|
|
:class:`.ExecutionContext`.
|
|
|
|
See :class:`.ExecutionContext` for details.
|
|
|
|
"""
|
|
|
|
return self.context.lastrow_has_defaults()
|
|
|
|
def postfetch_cols(self):
|
|
"""Return ``postfetch_cols()`` from the underlying
|
|
:class:`.ExecutionContext`.
|
|
|
|
See :class:`.ExecutionContext` for details.
|
|
|
|
Raises :class:`~sqlalchemy.exc.InvalidRequestError` if the executed
|
|
statement is not a compiled expression construct
|
|
or is not an insert() or update() construct.
|
|
|
|
"""
|
|
|
|
if not self.context.compiled:
|
|
raise exc.InvalidRequestError(
|
|
"Statement is not a compiled "
|
|
"expression construct.")
|
|
elif not self.context.isinsert and not self.context.isupdate:
|
|
raise exc.InvalidRequestError(
|
|
"Statement is not an insert() or update() "
|
|
"expression construct.")
|
|
return self.context.postfetch_cols
|
|
|
|
def prefetch_cols(self):
|
|
"""Return ``prefetch_cols()`` from the underlying
|
|
:class:`.ExecutionContext`.
|
|
|
|
See :class:`.ExecutionContext` for details.
|
|
|
|
Raises :class:`~sqlalchemy.exc.InvalidRequestError` if the executed
|
|
statement is not a compiled expression construct
|
|
or is not an insert() or update() construct.
|
|
|
|
"""
|
|
|
|
if not self.context.compiled:
|
|
raise exc.InvalidRequestError(
|
|
"Statement is not a compiled "
|
|
"expression construct.")
|
|
elif not self.context.isinsert and not self.context.isupdate:
|
|
raise exc.InvalidRequestError(
|
|
"Statement is not an insert() or update() "
|
|
"expression construct.")
|
|
return self.context.prefetch_cols
|
|
|
|
def supports_sane_rowcount(self):
|
|
"""Return ``supports_sane_rowcount`` from the dialect.
|
|
|
|
See :attr:`.ResultProxy.rowcount` for background.
|
|
|
|
"""
|
|
|
|
return self.dialect.supports_sane_rowcount
|
|
|
|
def supports_sane_multi_rowcount(self):
|
|
"""Return ``supports_sane_multi_rowcount`` from the dialect.
|
|
|
|
See :attr:`.ResultProxy.rowcount` for background.
|
|
|
|
"""
|
|
|
|
return self.dialect.supports_sane_multi_rowcount
|
|
|
|
def _fetchone_impl(self):
|
|
try:
|
|
return self.cursor.fetchone()
|
|
except AttributeError:
|
|
self._non_result()
|
|
|
|
def _fetchmany_impl(self, size=None):
|
|
try:
|
|
if size is None:
|
|
return self.cursor.fetchmany()
|
|
else:
|
|
return self.cursor.fetchmany(size)
|
|
except AttributeError:
|
|
self._non_result()
|
|
|
|
def _fetchall_impl(self):
|
|
try:
|
|
return self.cursor.fetchall()
|
|
except AttributeError:
|
|
self._non_result()
|
|
|
|
def _non_result(self):
|
|
if self._metadata is None:
|
|
raise exc.ResourceClosedError(
|
|
"This result object does not return rows. "
|
|
"It has been closed automatically.",
|
|
)
|
|
else:
|
|
raise exc.ResourceClosedError("This result object is closed.")
|
|
|
|
def process_rows(self, rows):
|
|
process_row = self._process_row
|
|
metadata = self._metadata
|
|
keymap = metadata._keymap
|
|
processors = metadata._processors
|
|
if self._echo:
|
|
log = self.context.engine.logger.debug
|
|
l = []
|
|
for row in rows:
|
|
log("Row %r", row)
|
|
l.append(process_row(metadata, row, processors, keymap))
|
|
return l
|
|
else:
|
|
return [process_row(metadata, row, processors, keymap)
|
|
for row in rows]
|
|
|
|
def fetchall(self):
|
|
"""Fetch all rows, just like DB-API ``cursor.fetchall()``."""
|
|
|
|
try:
|
|
l = self.process_rows(self._fetchall_impl())
|
|
self.close()
|
|
return l
|
|
except Exception as e:
|
|
self.connection._handle_dbapi_exception(
|
|
e, None, None,
|
|
self.cursor, self.context)
|
|
|
|
def fetchmany(self, size=None):
|
|
"""Fetch many rows, just like DB-API
|
|
``cursor.fetchmany(size=cursor.arraysize)``.
|
|
|
|
If rows are present, the cursor remains open after this is called.
|
|
Else the cursor is automatically closed and an empty list is returned.
|
|
|
|
"""
|
|
|
|
try:
|
|
l = self.process_rows(self._fetchmany_impl(size))
|
|
if len(l) == 0:
|
|
self.close()
|
|
return l
|
|
except Exception as e:
|
|
self.connection._handle_dbapi_exception(
|
|
e, None, None,
|
|
self.cursor, self.context)
|
|
|
|
def fetchone(self):
|
|
"""Fetch one row, just like DB-API ``cursor.fetchone()``.
|
|
|
|
If a row is present, the cursor remains open after this is called.
|
|
Else the cursor is automatically closed and None is returned.
|
|
|
|
"""
|
|
try:
|
|
row = self._fetchone_impl()
|
|
if row is not None:
|
|
return self.process_rows([row])[0]
|
|
else:
|
|
self.close()
|
|
return None
|
|
except Exception as e:
|
|
self.connection._handle_dbapi_exception(
|
|
e, None, None,
|
|
self.cursor, self.context)
|
|
|
|
def first(self):
|
|
"""Fetch the first row and then close the result set unconditionally.
|
|
|
|
Returns None if no row is present.
|
|
|
|
"""
|
|
if self._metadata is None:
|
|
self._non_result()
|
|
|
|
try:
|
|
row = self._fetchone_impl()
|
|
except Exception as e:
|
|
self.connection._handle_dbapi_exception(
|
|
e, None, None,
|
|
self.cursor, self.context)
|
|
|
|
try:
|
|
if row is not None:
|
|
return self.process_rows([row])[0]
|
|
else:
|
|
return None
|
|
finally:
|
|
self.close()
|
|
|
|
def scalar(self):
|
|
"""Fetch the first column of the first row, and close the result set.
|
|
|
|
Returns None if no row is present.
|
|
|
|
"""
|
|
row = self.first()
|
|
if row is not None:
|
|
return row[0]
|
|
else:
|
|
return None
|
|
|
|
|
|
class BufferedRowResultProxy(ResultProxy):
|
|
"""A ResultProxy with row buffering behavior.
|
|
|
|
``ResultProxy`` that buffers the contents of a selection of rows
|
|
before ``fetchone()`` is called. This is to allow the results of
|
|
``cursor.description`` to be available immediately, when
|
|
interfacing with a DB-API that requires rows to be consumed before
|
|
this information is available (currently psycopg2, when used with
|
|
server-side cursors).
|
|
|
|
The pre-fetching behavior fetches only one row initially, and then
|
|
grows its buffer size by a fixed amount with each successive need
|
|
for additional rows up to a size of 100.
|
|
"""
|
|
|
|
def _init_metadata(self):
|
|
self.__buffer_rows()
|
|
super(BufferedRowResultProxy, self)._init_metadata()
|
|
|
|
# this is a "growth chart" for the buffering of rows.
|
|
# each successive __buffer_rows call will use the next
|
|
# value in the list for the buffer size until the max
|
|
# is reached
|
|
size_growth = {
|
|
1: 5,
|
|
5: 10,
|
|
10: 20,
|
|
20: 50,
|
|
50: 100,
|
|
100: 250,
|
|
250: 500,
|
|
500: 1000
|
|
}
|
|
|
|
def __buffer_rows(self):
|
|
size = getattr(self, '_bufsize', 1)
|
|
self.__rowbuffer = collections.deque(self.cursor.fetchmany(size))
|
|
self._bufsize = self.size_growth.get(size, size)
|
|
|
|
def _fetchone_impl(self):
|
|
if self.closed:
|
|
return None
|
|
if not self.__rowbuffer:
|
|
self.__buffer_rows()
|
|
if not self.__rowbuffer:
|
|
return None
|
|
return self.__rowbuffer.popleft()
|
|
|
|
def _fetchmany_impl(self, size=None):
|
|
if size is None:
|
|
return self._fetchall_impl()
|
|
result = []
|
|
for x in range(0, size):
|
|
row = self._fetchone_impl()
|
|
if row is None:
|
|
break
|
|
result.append(row)
|
|
return result
|
|
|
|
def _fetchall_impl(self):
|
|
self.__rowbuffer.extend(self.cursor.fetchall())
|
|
ret = self.__rowbuffer
|
|
self.__rowbuffer = collections.deque()
|
|
return ret
|
|
|
|
|
|
class FullyBufferedResultProxy(ResultProxy):
|
|
"""A result proxy that buffers rows fully upon creation.
|
|
|
|
Used for operations where a result is to be delivered
|
|
after the database conversation can not be continued,
|
|
such as MSSQL INSERT...OUTPUT after an autocommit.
|
|
|
|
"""
|
|
|
|
def _init_metadata(self):
|
|
super(FullyBufferedResultProxy, self)._init_metadata()
|
|
self.__rowbuffer = self._buffer_rows()
|
|
|
|
def _buffer_rows(self):
|
|
return collections.deque(self.cursor.fetchall())
|
|
|
|
def _fetchone_impl(self):
|
|
if self.__rowbuffer:
|
|
return self.__rowbuffer.popleft()
|
|
else:
|
|
return None
|
|
|
|
def _fetchmany_impl(self, size=None):
|
|
if size is None:
|
|
return self._fetchall_impl()
|
|
result = []
|
|
for x in range(0, size):
|
|
row = self._fetchone_impl()
|
|
if row is None:
|
|
break
|
|
result.append(row)
|
|
return result
|
|
|
|
def _fetchall_impl(self):
|
|
ret = self.__rowbuffer
|
|
self.__rowbuffer = collections.deque()
|
|
return ret
|
|
|
|
|
|
class BufferedColumnRow(RowProxy):
|
|
def __init__(self, parent, row, processors, keymap):
|
|
# preprocess row
|
|
row = list(row)
|
|
# this is a tad faster than using enumerate
|
|
index = 0
|
|
for processor in parent._orig_processors:
|
|
if processor is not None:
|
|
row[index] = processor(row[index])
|
|
index += 1
|
|
row = tuple(row)
|
|
super(BufferedColumnRow, self).__init__(parent, row,
|
|
processors, keymap)
|
|
|
|
|
|
class BufferedColumnResultProxy(ResultProxy):
|
|
"""A ResultProxy with column buffering behavior.
|
|
|
|
``ResultProxy`` that loads all columns into memory each time
|
|
fetchone() is called. If fetchmany() or fetchall() are called,
|
|
the full grid of results is fetched. This is to operate with
|
|
databases where result rows contain "live" results that fall out
|
|
of scope unless explicitly fetched. Currently this includes
|
|
cx_Oracle LOB objects.
|
|
|
|
"""
|
|
|
|
_process_row = BufferedColumnRow
|
|
|
|
def _init_metadata(self):
|
|
super(BufferedColumnResultProxy, self)._init_metadata()
|
|
metadata = self._metadata
|
|
# orig_processors will be used to preprocess each row when they are
|
|
# constructed.
|
|
metadata._orig_processors = metadata._processors
|
|
# replace the all type processors by None processors.
|
|
metadata._processors = [None for _ in range(len(metadata.keys))]
|
|
keymap = {}
|
|
for k, (func, obj, index) in metadata._keymap.items():
|
|
keymap[k] = (None, obj, index)
|
|
self._metadata._keymap = keymap
|
|
|
|
def fetchall(self):
|
|
# can't call cursor.fetchall(), since rows must be
|
|
# fully processed before requesting more from the DBAPI.
|
|
l = []
|
|
while True:
|
|
row = self.fetchone()
|
|
if row is None:
|
|
break
|
|
l.append(row)
|
|
return l
|
|
|
|
def fetchmany(self, size=None):
|
|
# can't call cursor.fetchmany(), since rows must be
|
|
# fully processed before requesting more from the DBAPI.
|
|
if size is None:
|
|
return self.fetchall()
|
|
l = []
|
|
for i in range(size):
|
|
row = self.fetchone()
|
|
if row is None:
|
|
break
|
|
l.append(row)
|
|
return l
|