import cx_Oracle
from django.db.backends.oracle.introspection import DatabaseIntrospection
class OracleIntrospection(DatabaseIntrospection):
# Associating any OBJECTVAR instances with GeometryField. Of course,
# this won't work right on Oracle objects that aren't MDSYS.SDO_GEOMETRY,
# but it is the only object type supported within Django anyways.
data_types_reverse = DatabaseIntrospection.data_types_reverse.copy()
data_types_reverse[cx_Oracle.OBJECT] = 'GeometryField'
def get_geometry_type(self, table_name, geo_col):
cursor = self.connection.cursor()
try:
# Querying USER_SDO_GEOM_METADATA to get the SRID and dimension information.
try:
cursor.execute('SELECT "DIMINFO", "SRID" FROM "USER_SDO_GEOM_METADATA" WHERE "TABLE_NAME"=%s AND "COLUMN_NAME"=%s',
(table_name.upper(), geo_col.upper()))
row = cursor.fetchone()
except Exception, msg:
raise Exception('Could not find entry in USER_SDO_GEOM_METADATA corresponding to "%s"."%s"\n'
'Error message: %s.' % (table_name, geo_col, msg))
# TODO: Research way to find a more specific geometry field type for
# the column's contents.
field_type = 'GeometryField'
# Getting the field parameters.
field_params = {}
dim, srid = row
if srid != 4326:
field_params['srid'] = srid
# Length of object array ( SDO_DIM_ARRAY ) is number of dimensions.
dim = len(dim)
if dim != 2:
field_params['dim'] = dim
finally:
cursor.close()
return field_type, field_params
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