39 lines
1.6 KiB
Python
39 lines
1.6 KiB
Python
from django.db.backends.postgresql.schema import DatabaseSchemaEditor
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class PostGISSchemaEditor(DatabaseSchemaEditor):
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geom_index_type = 'GIST'
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geom_index_ops_nd = 'GIST_GEOMETRY_OPS_ND'
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rast_index_wrapper = 'ST_ConvexHull(%s)'
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def geo_quote_name(self, name):
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return self.connection.ops.geo_quote_name(name)
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def _field_should_be_indexed(self, model, field):
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if getattr(field, 'spatial_index', False):
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return True
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return super(PostGISSchemaEditor, self)._field_should_be_indexed(model, field)
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def _create_index_sql(self, model, fields, suffix="", sql=None):
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if len(fields) != 1 or not hasattr(fields[0], 'geodetic'):
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return super(PostGISSchemaEditor, self)._create_index_sql(model, fields, suffix=suffix, sql=sql)
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field = fields[0]
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field_column = self.quote_name(field.column)
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if field.geom_type == 'RASTER':
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# For raster fields, wrap index creation SQL statement with ST_ConvexHull.
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# Indexes on raster columns are based on the convex hull of the raster.
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field_column = self.rast_index_wrapper % field_column
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elif field.dim > 2 and not field.geography:
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# Use "nd" ops which are fast on multidimensional cases
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field_column = "%s %s" % (field_column, self.geom_index_ops_nd)
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return self.sql_create_index % {
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"name": self.quote_name('%s_%s_id' % (model._meta.db_table, field.column)),
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"table": self.quote_name(model._meta.db_table),
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"using": "USING %s" % self.geom_index_type,
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"columns": field_column,
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"extra": '',
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}
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