def _gen_label(self, name):
t = self.table
if self.is_literal:
return None
elif t is not None and t.named_with_column:
if getattr(t, 'schema', None):
label = t.schema.replace('.', '_') + "_" + \
t.name + "_" + name
else:
label = t.name + "_" + name
# propagate name quoting rules for labels.
if getattr(name, "quote", None) is not None:
if isinstance(label, quoted_name):
label.quote = name.quote
else:
label = quoted_name(label, name.quote)
elif getattr(t.name, "quote", None) is not None:
# can't get this situation to occur, so let's
# assert false on it for now
assert not isinstance(label, quoted_name)
label = quoted_name(label, t.name.quote)
# ensure the label name doesn't conflict with that
# of an existing column
if label in t.c:
_label = label
counter = 1
while _label in t.c:
_label = label + "_" + str(counter)
counter += 1
label = _label
return _as_truncated(label)
else:
return name
python类table()的实例源码
def __init__(self, element, values):
Annotated.__init__(self, element, values)
ColumnElement.comparator._reset(self)
for attr in ('name', 'key', 'table'):
if self.__dict__.get(attr, False) is None:
self.__dict__.pop(attr)
def table(self):
"""pull 'table' from parent, if not present"""
return self._Annotated__element.table
def define_tables(cls, metadata):
cls.tables.percent_table = Table('percent%table', metadata,
Column("percent%", Integer),
Column(
"spaces % more spaces", Integer),
)
cls.tables.lightweight_percent_table = sql.table(
'percent%table', sql.column("percent%"),
sql.column("spaces % more spaces")
)
def __init__(self, *clauses, **kw):
"""Return a :class:`.Tuple`.
Main usage is to produce a composite IN construct::
from sqlalchemy import tuple_
tuple_(table.c.col1, table.c.col2).in_(
[(1, 2), (5, 12), (10, 19)]
)
.. warning::
The composite IN construct is not supported by all backends,
and is currently known to work on Postgresql and MySQL,
but not SQLite. Unsupported backends will raise
a subclass of :class:`~sqlalchemy.exc.DBAPIError` when such
an expression is invoked.
"""
clauses = [_literal_as_binds(c) for c in clauses]
self._type_tuple = [arg.type for arg in clauses]
self.type = kw.pop('type_', self._type_tuple[0]
if self._type_tuple else type_api.NULLTYPE)
super(Tuple, self).__init__(*clauses, **kw)
def literal_column(text, type_=None):
"""Produce a :class:`.ColumnClause` object that has the
:paramref:`.column.is_literal` flag set to True.
:func:`.literal_column` is similar to :func:`.column`, except that
it is more often used as a "standalone" column expression that renders
exactly as stated; while :func:`.column` stores a string name that
will be assumed to be part of a table and may be quoted as such,
:func:`.literal_column` can be that, or any other arbitrary column-oriented
expression.
:param text: the text of the expression; can be any SQL expression.
Quoting rules will not be applied. To specify a column-name expression
which should be subject to quoting rules, use the :func:`column`
function.
:param type\_: an optional :class:`~sqlalchemy.types.TypeEngine`
object which will
provide result-set translation and additional expression semantics for
this column. If left as None the type will be NullType.
.. seealso::
:func:`.column`
:func:`.text`
:ref:`sqlexpression_literal_column`
"""
return ColumnClause(text, type_=type_, is_literal=True)
def _get_table(self):
return self.__dict__['table']
def _set_table(self, table):
self._memoized_property.expire_instance(self)
self.__dict__['table'] = table
def _from_objects(self):
t = self.table
if t is not None:
return [t]
else:
return []
def _render_label_in_columns_clause(self):
return self.table is not None
def _gen_label(self, name):
t = self.table
if self.is_literal:
return None
elif t is not None and t.named_with_column:
if getattr(t, 'schema', None):
label = t.schema.replace('.', '_') + "_" + \
t.name + "_" + name
else:
label = t.name + "_" + name
# propagate name quoting rules for labels.
if getattr(name, "quote", None) is not None:
if isinstance(label, quoted_name):
label.quote = name.quote
else:
label = quoted_name(label, name.quote)
elif getattr(t.name, "quote", None) is not None:
# can't get this situation to occur, so let's
# assert false on it for now
assert not isinstance(label, quoted_name)
label = quoted_name(label, t.name.quote)
# ensure the label name doesn't conflict with that
# of an existing column
if label in t.c:
_label = label
counter = 1
while _label in t.c:
_label = label + "_" + str(counter)
counter += 1
label = _label
return _as_truncated(label)
else:
return name
def __init__(self, element, values):
Annotated.__init__(self, element, values)
ColumnElement.comparator._reset(self)
for attr in ('name', 'key', 'table'):
if self.__dict__.get(attr, False) is None:
self.__dict__.pop(attr)
def table(self):
"""pull 'table' from parent, if not present"""
return self._Annotated__element.table
def define_tables(cls, metadata):
cls.tables.percent_table = Table('percent%table', metadata,
Column("percent%", Integer),
Column(
"spaces % more spaces", Integer),
)
cls.tables.lightweight_percent_table = sql.table(
'percent%table', sql.column("percent%"),
sql.column("spaces % more spaces")
)
def __init__(self, *clauses, **kw):
"""Return a :class:`.Tuple`.
Main usage is to produce a composite IN construct::
from sqlalchemy import tuple_
tuple_(table.c.col1, table.c.col2).in_(
[(1, 2), (5, 12), (10, 19)]
)
.. warning::
The composite IN construct is not supported by all backends,
and is currently known to work on Postgresql and MySQL,
but not SQLite. Unsupported backends will raise
a subclass of :class:`~sqlalchemy.exc.DBAPIError` when such
an expression is invoked.
"""
clauses = [_literal_as_binds(c) for c in clauses]
self._type_tuple = [arg.type for arg in clauses]
self.type = kw.pop('type_', self._type_tuple[0]
if self._type_tuple else type_api.NULLTYPE)
super(Tuple, self).__init__(*clauses, **kw)
def literal_column(text, type_=None):
"""Produce a :class:`.ColumnClause` object that has the
:paramref:`.column.is_literal` flag set to True.
:func:`.literal_column` is similar to :func:`.column`, except that
it is more often used as a "standalone" column expression that renders
exactly as stated; while :func:`.column` stores a string name that
will be assumed to be part of a table and may be quoted as such,
:func:`.literal_column` can be that, or any other arbitrary column-oriented
expression.
:param text: the text of the expression; can be any SQL expression.
Quoting rules will not be applied. To specify a column-name expression
which should be subject to quoting rules, use the :func:`column`
function.
:param type\_: an optional :class:`~sqlalchemy.types.TypeEngine`
object which will
provide result-set translation and additional expression semantics for
this column. If left as None the type will be NullType.
.. seealso::
:func:`.column`
:func:`.text`
:ref:`sqlexpression_literal_column`
"""
return ColumnClause(text, type_=type_, is_literal=True)
def _get_table(self):
return self.__dict__['table']
def _set_table(self, table):
self._memoized_property.expire_instance(self)
self.__dict__['table'] = table
def _from_objects(self):
t = self.table
if t is not None:
return [t]
else:
return []
def _gen_label(self, name):
t = self.table
if self.is_literal:
return None
elif t is not None and t.named_with_column:
if getattr(t, 'schema', None):
label = t.schema.replace('.', '_') + "_" + \
t.name + "_" + name
else:
label = t.name + "_" + name
# propagate name quoting rules for labels.
if getattr(name, "quote", None) is not None:
if isinstance(label, quoted_name):
label.quote = name.quote
else:
label = quoted_name(label, name.quote)
elif getattr(t.name, "quote", None) is not None:
# can't get this situation to occur, so let's
# assert false on it for now
assert not isinstance(label, quoted_name)
label = quoted_name(label, t.name.quote)
# ensure the label name doesn't conflict with that
# of an existing column
if label in t.c:
_label = label
counter = 1
while _label in t.c:
_label = label + "_" + str(counter)
counter += 1
label = _label
return _as_truncated(label)
else:
return name
