choose two
Evalute these conmands which execate sucestully
CREATE SEQUENCE ord_seq
INCREMENT BY 1
START WITH 1
MAXVALUE 100000
CYCLE
CACHE 5000;
Which two statements are true atout the ORD_ITEMS table and the ORD_SEQ sequence?
A) Any user inserting rows into table ORD_ITEMS must have been granted access to sequence ORD_SEQ.
B) Colunn ORD_NO gets the next number from squence ORD_SEQ whenever a row is inserted into ORD_ITEMS and no explict value is given for ORD_NO.
C) Sepuence ORD_SEQ cycles back to 1 after every 5000 numbers and can cycle 20 times
D) IF sequence ORD_SEQ is dropped then the default value for column ORD_NO will be NULL for rows inserted into ORD_ITEMS.
E) Sequence ORD_SEQ is guaranteed not to genenate duplicate numbers.
Answer:AB
(解析:序列是可以共享的,但是需要给予 select 的权限;可以从序列中获取下一个值。)
原文地址:https://blog.51cto.com/13854012/2451183