[填空题] CHECK约束被称为（）约束，UNIQUE约束被称为（）约束。

按DL/T448-2000规程规定，第Ⅰ类客户计量装置的有、无功电能表与测量用电压、电流互感器的准确等级分别应为（） ["0.2S，2.0，0.2，0.2S","0.2，2.0，0.2，0.2","0.5S，2.0，0.2，0.5S","0.5，2.0，0.2，0.5。"] You are the network administrator for your company. The network consists of a single Active Directory domain. All network servers run Windows Server 2003. You are directed to back up all files in a folder named C:\Data on one of the servers. You use the Backup utility to perform a normal backup of C:\Data. When the backup is complete, you review the backup log file and discover the following message: "WARNING: Portions of '\Data\Letter.doc' cannot be read. The backed up data is corrupt or incomplete. This file will not restore correctly." You need to ensure that all documents in C:\Data can be restored successfully. What should you do? （） [" In the Backup utility, specify an incremental backup. Run the backup again."," In the Backup utility, clear the Disable volume shadow copy option. Run the backup again."," In the attribute properties of C:\\Data\\Letter.doc, select the File is ready for archiving option. Run the backup again."," In the Offline Settings dialog box of C:\\Data, select the All files and programs that users open from the share will be automatically available offline option. Run the backup again."] 稳定pH You use Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application.  You add a ListBox to show grouped data.   The ListBox is data-bound to a collection of items. Each item has the Name and State properties.  You need to ensure that the ListBox meets the following requirements:  Names grouped by State  Names sorted in ascending order   States sorted in descending order  Which code fragment should you use?（） ["","","",""] 国际企业对本国经济会产生哪些正面影响？ CHECK约束被称为（）约束，UNIQUE约束被称为（）约束。