105 lines
3.0 KiB
Python
105 lines
3.0 KiB
Python
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from sqlalchemy import types as sqltypes
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from sqlalchemy.sql.expression import (
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ClauseList, Function, _literal_as_binds, text, _type_from_args
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)
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from sqlalchemy.sql import operators
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from sqlalchemy.sql.visitors import VisitableType
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class _GenericMeta(VisitableType):
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def __call__(self, *args, **kwargs):
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args = [_literal_as_binds(c) for c in args]
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return type.__call__(self, *args, **kwargs)
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class GenericFunction(Function):
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__metaclass__ = _GenericMeta
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def __init__(self, type_=None, args=(), **kwargs):
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self.packagenames = []
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self.name = self.__class__.__name__
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self._bind = kwargs.get('bind', None)
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self.clause_expr = ClauseList(
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operator=operators.comma_op,
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group_contents=True, *args).self_group()
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self.type = sqltypes.to_instance(
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type_ or getattr(self, '__return_type__', None))
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class AnsiFunction(GenericFunction):
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def __init__(self, **kwargs):
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GenericFunction.__init__(self, **kwargs)
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class ReturnTypeFromArgs(GenericFunction):
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"""Define a function whose return type is the same as its arguments."""
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def __init__(self, *args, **kwargs):
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kwargs.setdefault('type_', _type_from_args(args))
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GenericFunction.__init__(self, args=args, **kwargs)
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class coalesce(ReturnTypeFromArgs):
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pass
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class max(ReturnTypeFromArgs):
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pass
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class min(ReturnTypeFromArgs):
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pass
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class sum(ReturnTypeFromArgs):
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pass
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class now(GenericFunction):
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__return_type__ = sqltypes.DateTime
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class concat(GenericFunction):
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__return_type__ = sqltypes.String
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def __init__(self, *args, **kwargs):
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GenericFunction.__init__(self, args=args, **kwargs)
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class char_length(GenericFunction):
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__return_type__ = sqltypes.Integer
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def __init__(self, arg, **kwargs):
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GenericFunction.__init__(self, args=[arg], **kwargs)
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class random(GenericFunction):
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def __init__(self, *args, **kwargs):
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kwargs.setdefault('type_', None)
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GenericFunction.__init__(self, args=args, **kwargs)
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class count(GenericFunction):
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"""The ANSI COUNT aggregate function. With no arguments, emits COUNT \*."""
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__return_type__ = sqltypes.Integer
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def __init__(self, expression=None, **kwargs):
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if expression is None:
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expression = text('*')
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GenericFunction.__init__(self, args=(expression,), **kwargs)
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class current_date(AnsiFunction):
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__return_type__ = sqltypes.Date
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class current_time(AnsiFunction):
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__return_type__ = sqltypes.Time
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class current_timestamp(AnsiFunction):
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__return_type__ = sqltypes.DateTime
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class current_user(AnsiFunction):
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__return_type__ = sqltypes.String
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class localtime(AnsiFunction):
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__return_type__ = sqltypes.DateTime
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class localtimestamp(AnsiFunction):
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__return_type__ = sqltypes.DateTime
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class session_user(AnsiFunction):
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__return_type__ = sqltypes.String
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class sysdate(AnsiFunction):
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__return_type__ = sqltypes.DateTime
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class user(AnsiFunction):
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__return_type__ = sqltypes.String
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