Which two are true about Oracle‘s Optimizer statistics?
A)They are automatically updated when ddl statements execute.
B)They can be calculated exactly.
C)They can be gathered on external tables.
D)They are automatically updated when dml statements execute.
E)They can be estimated.
Answer: BE
赵：
estimated adj. 估计的;预计的;估算的;
原文：https://www.cnblogs.com/cnblogs5359/p/11262841.html