The following restrictions apply to CMP:
You can drop CMP indexes.
CMP indexes cannot be unique.
CMP indexes are not replicated in underlying join indexes.
Even though a CMP index can be created on columns defined as NULL, a partial width insert into a table is disallowed when not all columns of a CMP index are part of the insert.
An exception is raised if you attempt to alter or delete a column that is defined in a CMP index.
Users cannot ALTER TABLE MODIFY an existing column that is defined in a CMP index.
CMP indexes do not support the BIT, FLOAT, DOUBLE, and REAL data types.
