You are the administrator of a SQL Server 2000 computer. The server contains a database named Inventory. Users report that several storage locations in the UnitsStored field contain negative numbers. You examine the database's table structure. The table properties are configured as shown in the exhibit.

You correct all the negative numbers in the table. You must prevent the database from storing negative numbers. You also want to minimize use of server resources and physical I/O.
Which transact-SQL statement should you execute？
A．ALTER TABLE dbo.storagelocations ADD CONSTRAINTS CK_storagelocations_UnitsStored CHECK （UnitsStored>= 0)
B．CREATE TRIGGER CK_UnitsStored On StorageLocations FOR INSERT, UPDATE AS IF INSERTED, UnitsStored < 0 ROLLBACK TRAN
C．CREATE TABLE ck_unitsstored As @Units >= 0 GO Sp_bindrule ‘OK_UnitsStored’, ‘StorageLocations, UnitsStored’ GO
D．CREATE PROC UpdateUnitsStored （StorageLocationID int, @UnitsStored bigint)AS IF @UnitsStored < 0 DATSERROR （50099, 17) ELSE UPDATE storaheLocations SET UnitsStored = @UnitsStored WHERE StorageLocationID = @storageLocationID

The LAN needs are expanding at the Ezonexam corporate office, which is quickly growing. You are instructed to enlarge the area covered by a single LAN segment on the Ezonexam network.
Which of the following are layer 1 devices that you can use？ （Choose all that apply.)
A．A switch
B．A router
C．A network adapter card
D．A hub
E．A repeater

外频是用来表示CPU的运算速度。（）

此题为判断题（对，错)。

When is a switched network that is running the Spanning Tree Protocol considered to be fully converged？
A．when all switches have the same BID as the root switch
B．when all switches have received the MAC address of each neighboring switch
C．when every enabled switch port has been assigned a unique identifier
D．when every operating switch port is in either the blocking or forwarding state
E．when all switches are in either client, server, or transparent mode

主频也较时钟频率，单位是HZ。（）

此题为判断题（对，错)。

The Ezonexam network administrator has just issued the "switchport trunk native vlan 998" command on switch VE2. What is the function of this command？
A．It designates VLAN 998 as the default for all unknown tagged traffic
B．It designates VLAN 998 for untagged traffic
C．It blocks VLAN 998 traffic from passing on the trunk
D．It creates a VLAN 998 interface
E．None of the above