25 lines
582 B
Python
25 lines
582 B
Python
"""
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Useful auxiliary data structures for query construction. Not useful outside
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the SQL domain.
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"""
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class EmptyResultSet(Exception):
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pass
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class MultiJoin(Exception):
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"""
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Used by join construction code to indicate the point at which a
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multi-valued join was attempted (if the caller wants to treat that
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exceptionally).
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"""
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def __init__(self, names_pos, path_with_names):
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self.level = names_pos
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# The path travelled, this includes the path to the multijoin.
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self.names_with_path = path_with_names
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class Empty(object):
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pass
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