48 lines
1.8 KiB
Python
48 lines
1.8 KiB
Python
import cx_Oracle
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from django.db.backends.oracle.introspection import DatabaseIntrospection
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from django.utils.functional import cached_property
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class OracleIntrospection(DatabaseIntrospection):
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# Associating any OBJECTVAR instances with GeometryField. This won't work
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# right on Oracle objects that aren't MDSYS.SDO_GEOMETRY, but it is the
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# only object type supported within Django anyways.
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@cached_property
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def data_types_reverse(self):
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return {
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**super().data_types_reverse,
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cx_Oracle.OBJECT: 'GeometryField',
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}
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def get_geometry_type(self, table_name, description):
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with self.connection.cursor() as cursor:
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# Querying USER_SDO_GEOM_METADATA to get the SRID and dimension information.
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try:
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cursor.execute(
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'SELECT "DIMINFO", "SRID" FROM "USER_SDO_GEOM_METADATA" '
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'WHERE "TABLE_NAME"=%s AND "COLUMN_NAME"=%s',
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(table_name.upper(), description.name.upper())
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)
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row = cursor.fetchone()
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except Exception as exc:
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raise Exception(
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'Could not find entry in USER_SDO_GEOM_METADATA '
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'corresponding to "%s"."%s"' % (table_name, description.name)
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) from exc
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# TODO: Research way to find a more specific geometry field type for
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# the column's contents.
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field_type = 'GeometryField'
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# Getting the field parameters.
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field_params = {}
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dim, srid = row
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if srid != 4326:
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field_params['srid'] = srid
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# Size of object array (SDO_DIM_ARRAY) is number of dimensions.
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dim = dim.size()
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if dim != 2:
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field_params['dim'] = dim
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return field_type, field_params
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