Which constraint can be defines only at the column level? ()
- A UNIQUE
- B NOT NULL
- C CHECK
- D PRIMARY KEY
- E FOREIGN KEY
Which constraint can be defines only at the column level? ()
1、Which operator can be used with a mult
Which operator can be used with a multiple-row subquery? ()A =B LIKEC BETWEEND NOT INE ISF <>
2、Which command can be used from a PC to
Which command can be used from a PC to verfy the connectivity between host that connect through path?()A tracert addressB ping addressC arp addressD traceroute addre
3、Which of the following can be a disadv
Which of the following can be a disadvantage of search agents?AA Lack of counseling.BB Limited number of visits.CC Lower efficiency. D Fewer successful matches.
4、A body can only be observed at lower t
A body can only be observed at lower transit when().Athe declination is the opposite name to the latitudeBthe algebraic sum of the colatitude...
5、One function of a language can only be
One function of a language can only be expressed by one structure.()A正确B错误
6、● In (74) the only element that can be
● In (74) the only element that can be deleted or removed is the one that was inserted most recently.(74)A a lineB a queueC an arrayD a stack