Cause
An attempt was made to use the CASCADE option with DROP CONSTRAINT ONLINE statement.
An attempt was made to use the CASCADE option with DROP CONSTRAINT ONLINE statement.
Using online DDL's like DROP INDEX ONLINE, ALTER TABLE DROP CONSTRAINT ONLINE, or ALTER TABLE SET UNUSED COLUMN ONLINE statement on certain types of tables (for example, cluster, temporary, indexed-organized table (IOT), external tables) is illegal. Remove the ONLINE keyword from the statement.
Try the following links for this error:
http://docs.oracle.com/cd/E16655_01/server.121/e26079/e12700.htm
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