Cause
The datatype of the column present in the table is different from the datatype set for the policy column.
The datatype of the column present in the table is different from the datatype set for the policy column.
Drop the column on the table or change the datatype for policy column.
Try the following links for this error:
http://docs.oracle.com/cd/E16655_01/server.121/e26079/e12400.htm
https://community.oracle.com/message/4049076
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