有如下程序段：其中会产生编译错误的语句是（　　）。

A、④

B、③

C、②

D、①

The following commands are available in the Linux binary distributions of Mysql: Mysqld Mysqld_safe Mysql.server What is the correct description of each of these commands?（）

A、 A

B、 B

C、 C

D、 D

以下哪个公式为计算活动历史提供了最精确的结果（）？

A、AD=工作数量/生产速率

B、AD=工作数量/资源的数量

C、AD=工作数量/工作数量

D、AD=（生产速率×工作数量）/资源的数量

The validate_password plugin is loaded and displays the following settings in global variables: Mysql＞ SHOW VARIABLES LIKE ‘validate_password%’; When attempting to set your password, you get the following error: Mysql＞ SET PASSWORD = PASSWORD (‘Hoverl@%’); ERROR 1819 (HY000): Your password does not satisfy the current policy requirements What is the cause of the error?（）

A、 The password is eight characters long, but needs to exceed validate_password_length to be valid

B、 All of the MEDIUM password policy requirements have not been honored

C、 The password matches a substring Hover as a dictionary word

D、 The password does not match the validate_passoword_number_count requirement

E、 There is no dictionary file defined, so password validation cannot work as expected

Which three statements are characteristic of the MEMORY storage engine?（）

It can support transactions

Table contents are not saved if the server is restarted

It cannot contain text or BLOB columns

It can support foreign keys

Each table is represented on disk as an.frm file

Each table has a corresponding.MYI and .MYD file

Click the Exhibit button. In the exhibit, you decided to change myHosts addresses.What will happen to the new sessions matching the policy and in-progress sessions that had already matched the policy?（）

A、 New sessions will be evaluated. In-progress sessions will be re-evaluated.

B、 New sessions will be evaluated. All in-progress sessions will continue.

C、 New sessions will be evaluated. All in-progress sessions will be dropped.

D、 New sessions will halt until all in-progress sessions are re-evaluated. In-progress sessions will be re-evaluated.