86 lines
3.4 KiB
Python
86 lines
3.4 KiB
Python
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from django.db.backends.postgresql_psycopg2.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 = 'GIST_GEOMETRY_OPS'
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geom_index_ops_nd = 'GIST_GEOMETRY_OPS_ND'
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sql_add_geometry_column = "SELECT AddGeometryColumn(%(table)s, %(column)s, %(srid)s, %(geom_type)s, %(dim)s)"
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sql_alter_geometry_column_not_null = "ALTER TABLE %(table)s ALTER COLUMN %(column)s SET NOT NULL"
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sql_add_spatial_index = "CREATE INDEX %(index)s ON %(table)s USING %(index_type)s (%(column)s %(ops)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 create_model(self, model):
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from django.contrib.gis.db.models.fields import GeometryField
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# Do model creation first
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super(PostGISSchemaEditor, self).create_model(model)
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# Now add any spatial field SQL
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sqls = []
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for field in model._meta.local_fields:
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if isinstance(field, GeometryField):
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sqls.extend(self.spatial_field_sql(model, field))
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for sql in sqls:
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self.execute(sql)
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def spatial_field_sql(self, model, field):
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"""
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Takes a GeometryField and returns a list of SQL to execute to
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create its spatial indexes.
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"""
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output = []
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if field.geography or self.connection.ops.geometry:
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# Geography and Geometry (PostGIS 2.0+) columns are
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# created normally.
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pass
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else:
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# Geometry columns are created by the `AddGeometryColumn`
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# stored procedure.
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output.append(
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self.sql_add_geometry_column % {
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"table": self.geo_quote_name(model._meta.db_table),
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"column": self.geo_quote_name(field.column),
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"srid": field.srid,
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"geom_type": self.geo_quote_name(field.geom_type),
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"dim": field.dim,
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}
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)
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if not field.null:
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output.append(
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self.sql_alter_geometry_column_not_null % {
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"table": self.quote_name(model._meta.db_table),
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"column": self.quote_name(field.column),
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},
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)
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if field.spatial_index:
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# Spatial indexes created the same way for both Geometry and
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# Geography columns.
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# PostGIS 2.0 does not support GIST_GEOMETRY_OPS. So, on 1.5
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# we use GIST_GEOMETRY_OPS, on 2.0 we use either "nd" ops
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# which are fast on multidimensional cases, or just plain
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# gist index for the 2d case.
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if field.geography:
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index_ops = ''
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elif self.connection.ops.geometry:
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if field.dim > 2:
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index_ops = self.geom_index_ops_nd
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else:
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index_ops = ''
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else:
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index_ops = self.geom_index_ops
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output.append(
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self.sql_add_spatial_index % {
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"index": 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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"column": self.quote_name(field.column),
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"index_type": self.geom_index_type,
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"ops": index_ops,
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}
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)
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return output
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