Format
SDO_CS.DETERMINE_CHAIN(
transient_rule_set IN SDO_TRANSIENT_RULE_SET,
use_case IN VARCHAR2,
source_srid IN NUMBER,
target_srid IN NUMBER) RETURN TFM_PLAN;Description
Returns the query chain, based on the system rule set, to be used in transformations from one coordinate reference system to another coordinate reference system.
Parameters
Rule set to be used for the transformation. If you specify a null value, the Oracle system rule set is used.
Use case for which to determine the query chain. Must be a null value or a value from the USE_CASE column of the SDO_PREFERRED_OPS_USER table (described in SDO_PREFERRED_OPS_USER Table).
The SRID of the source coordinate reference system. Must be a value in the SRID column of the SDO_COORD_REF_SYS table (described in SDO_COORD_REF_SYS Table).
The SRID of the target coordinate reference system. Must be a value in the SRID column of the SDO_COORD_REF_SYS table (described in SDO_COORD_REF_SYS Table).
Usage Notes
This function returns an object of type TFM_PLAN, which is explained in TFM_PLAN Object Type.
The transient_rule_set parameter is of type SDO_TRANSIENT_RULE_SET, which has the following definition:
CREATE TYPE sdo_transient_rule_set AS OBJECT ( source_srid NUMBER, target_srid NUMBER, tfm NUMBER);
Examples
The following example returns the query chain based on the system rule set.
SELECT MDSYS.SDO_CS.DETERMINE_CHAIN(NULL, NULL, 4804, 4257) FROM DUAL; MDSYS.SDO_CS.DETERMINE_CHAIN(NULL,NULL,4804,4257)(THE_PLAN) -------------------------------------------------------------------------------- TFM_PLAN(SDO_TFM_CHAIN(4804, -2, 4257))
The next example creates a preferred concatenated operation (with operation ID 300) with a specified chain for transformations from SRID 4804 to SRID 4257, and then calls the DETERMINE_CHAIN function, returning a different result. (The operation created in this example is not meaningful or useful, and it was created only for illustration.)
CALL SDO_CS.CREATE_PREF_CONCATENATED_OP(
300,
'CONCATENATED OPERATION',
TFM_PLAN(
SDO_TFM_CHAIN(
4804,
1000000001, 4804,
1000000002, 4804,
1000000001, 4804,
1000000001, 4804,
1000000002, 4804,
1000000002, 4804,
1000000001, 4804,
1000000001, 4804,
1000000001, 4804,
1000000002, 4804,
1000000002, 4804,
1000000002, 4257)),
NULL);
SELECT MDSYS.SDO_CS.DETERMINE_CHAIN(NULL, NULL, 4804, 4257) FROM DUAL;
MDSYS.SDO_CS.DETERMINE_CHAIN(NULL,NULL,4804,4257)(THE_PLAN)
--------------------------------------------------------------------------------
TFM_PLAN(SDO_TFM_CHAIN(4804, 300, 4257))