67 lines
2.2 KiB
Python
67 lines
2.2 KiB
Python
from django.contrib.gis.db.models.fields import ExtentField
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from django.db.models.aggregates import Aggregate
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__all__ = ['Collect', 'Extent', 'Extent3D', 'MakeLine', 'Union']
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class GeoAggregate(Aggregate):
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function = None
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is_extent = False
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def as_sql(self, compiler, connection, function=None, **extra_context):
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# this will be called again in parent, but it's needed now - before
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# we get the spatial_aggregate_name
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connection.ops.check_expression_support(self)
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return super().as_sql(
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compiler,
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connection,
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function=function or connection.ops.spatial_aggregate_name(self.name),
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**extra_context
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)
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def as_oracle(self, compiler, connection):
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tolerance = self.extra.get('tolerance') or getattr(self, 'tolerance', 0.05)
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template = None if self.is_extent else '%(function)s(SDOAGGRTYPE(%(expressions)s,%(tolerance)s))'
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return self.as_sql(compiler, connection, template=template, tolerance=tolerance)
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def resolve_expression(self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False):
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c = super().resolve_expression(query, allow_joins, reuse, summarize, for_save)
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for expr in c.get_source_expressions():
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if not hasattr(expr.field, 'geom_type'):
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raise ValueError('Geospatial aggregates only allowed on geometry fields.')
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return c
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class Collect(GeoAggregate):
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name = 'Collect'
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class Extent(GeoAggregate):
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name = 'Extent'
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is_extent = '2D'
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def __init__(self, expression, **extra):
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super().__init__(expression, output_field=ExtentField(), **extra)
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def convert_value(self, value, expression, connection, context):
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return connection.ops.convert_extent(value)
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class Extent3D(GeoAggregate):
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name = 'Extent3D'
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is_extent = '3D'
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def __init__(self, expression, **extra):
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super().__init__(expression, output_field=ExtentField(), **extra)
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def convert_value(self, value, expression, connection, context):
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return connection.ops.convert_extent3d(value)
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class MakeLine(GeoAggregate):
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name = 'MakeLine'
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class Union(GeoAggregate):
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name = 'Union'
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