Cause
An attempt was made to drop column from a partition/subpartition on a read only tablespace.
An attempt was made to drop column from a partition/subpartition on a read only tablespace.
Set the tablespace to read write and resubmit statement.
Try the following links for this error:
http://docs.oracle.com/cd/E16655_01/server.121/e26079/e12700.htm
https://community.oracle.com/message/1166924
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