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52 lines
1.7 KiB
52 lines
1.7 KiB
from types import UnicodeType |
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def gqn(val): |
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""" |
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The geographic quote name function; used for quoting tables and |
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geometries (they use single rather than the double quotes of the |
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backend quotename function). |
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""" |
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if isinstance(val, basestring): |
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if isinstance(val, UnicodeType): val = val.encode('ascii') |
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return "'%s'" % val |
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else: |
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return str(val) |
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class SpatialOperation(object): |
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""" |
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Base class for generating spatial SQL. |
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""" |
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def __init__(self, function='', operator='', result='', beg_subst='', end_subst=''): |
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self.function = function |
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self.operator = operator |
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self.result = result |
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self.beg_subst = beg_subst |
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try: |
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# Try and put the operator and result into to the |
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# end substitution. |
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self.end_subst = end_subst % (operator, result) |
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except TypeError: |
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self.end_subst = end_subst |
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@property |
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def sql_subst(self): |
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return ''.join([self.beg_subst, self.end_subst]) |
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def as_sql(self, geo_col): |
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return self.sql_subst % self.params(geo_col) |
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def params(self, geo_col): |
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return (geo_col, self.operator) |
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class SpatialFunction(SpatialOperation): |
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""" |
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Base class for generating spatial SQL related to a function. |
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""" |
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def __init__(self, func, beg_subst='%s(%s, %%s', end_subst=')', result='', operator=''): |
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# Getting the function prefix. |
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kwargs = {'function' : func, 'operator' : operator, 'result' : result, |
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'beg_subst' : beg_subst, 'end_subst' : end_subst,} |
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super(SpatialFunction, self).__init__(**kwargs) |
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def params(self, geo_col): |
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return (self.function, geo_col)
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