A.NOTNULL和UNIQUE B.UNIQUE和PRIMARYKEY C.UNIQUE和FOREIGNKEY D.PRIMARYKEY和FOREIGNKEY
A.ALTER INDEX ln_idx ON employees(first_name) B.ALTER INDEX ln_idx TO employees(first_name) C.ALTER INDEX ln_idx TO fn_idx ON employees(first_name) D.以上都不能;您無法變更索引
A.CREATE INDEX索引名ON表名(列名) B.CREATE INDEX ON表名(列名) C.CREATE索引名INDEX ON表名.列名 D.CREATE OR REPLACE INDEX索引名ON表名(列名)