How does an Transparent Gateway handle non-Oracle capabilities?
Oracle SQL Functions and Oracle capabilities that are not supported by the non-Oracle system can be still used in SELECT statements but not in DML statements. When these unsupported functions are used in SELECT statements, Oracle (HS) strips this function from teh SELECT statement and sends the SELECT statement to the gateway without the function reference. In the following example, assume SUBSTR funtion is not supported by the non-Oracle system that is being accessed via dblink, GTWLINK: Original Query: SELECT SUBSTR(ENAME,1,5) FROM EMP@GTWLINK; Statement sent to the gateway by Oracle: SELECT ENAME FROM EMP; If SUBSTR function is used with any DML statements, Oracle will raise an error.