A.CREATEINDEX會(huì)創(chuàng)建一個(gè)基于函數(shù)的索引 B.CREATEINDEX語(yǔ)句會(huì)創(chuàng)建一個(gè)非唯一索引 C.CREATEINDEX語(yǔ)句會(huì)創(chuàng)建一個(gè)唯一索引 D.因?yàn)檎Z(yǔ)法錯(cuò)誤,CREATEINDEX語(yǔ)句將失敗
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(wú)法變更索引