KEY Table Constraint
Table constraint to define an index key
KEY [<cTagName>] (column1[, column2,...])
A constraint is used to define rules that help to provide data integrity. TABLE constraints apply to table-based operations. You must have ALTER privilege on the table. The table will be locked for EXCLUSIVE use during the operation.
The KEY table constraint is used to define an index key. The index is built on the column or columns specified and given the name as defined in <cTagName>. The INDEX table constraint can be used in the same way.
CREATE TABLE contact; (LastName char(25), FirstName char(25),; KEY FullName (LastName, FirstName))