解析 C A. 错误。DLCI是帧中继网络中必需的标识符,用于确定数据路径,不能省略。B. 错误。DLCI对应逻辑虚电路(如PVC),而非物理电路。一个物理线路可承载多条逻辑连接。C. 正确。DLCI唯一标识DTE设备(如路由器)之间的逻辑连接,本地有效。D. 错误。LAN交换使用MAC地址,帧起始由其他机制标记,与DLCI无关。
Exists用于只能用于子查询,可以替代in,若匹配到结果,则退出内部查询,并将条件标志为true,传回全部结果资料,in不管匹配到匹配不到都全部匹配完毕,使用exists可以将子查询结果定为常量,不影响查询效果,而且效率高。如查询所有销售部门员工的姓名,对比如下: IN is often better if the results of the subquery are very...
Defines which rows have matches in joins. Example: ON left_table.a = right_table.a You are not advised to use numeric types such as int forjoin_condition, because such types can be implicitly converted to bool values (non-zero values are implicitly converted totrueand0is implicitly converted...
When two or more attributes of the dimension are used in a SELECT statement, Analysis Services evaluates the attributes' expressions to make sure that the members of those attributes are properly confined to meet the criteria of all other attributes. For example, suppose you are working with attr...
The model stays selected, but all other models are deselected.You can also use the exclusive option when calling .select() on a model, rather than the collection.m3.select( { exclusive: true } );When models are shared among multiple collections, it makes a difference whether you call ....
that is granting the License. "Legal Entity" shall mean the union of the acting entity and all other entities that control, are controlled by, or are under common control with that entity. For the purposes of this definition, "control" means (i) the power, direct or indirect, to cause ...
To allow customization and theming,ng-selectbundle includes only generic styles that are necessary for correct layout and positioning. To get full look of the control, include one of the themes in your application. If you're using the Angular CLI, you can add this to yourstyles.scssor includ...
Valid keys are: Name (or Label) -<string> Expression -<string>or<script block> For more information, seeabout_Calculated_Properties. Type:Object[] Position:0 Default value:None Required:False Accept pipeline input:False Accept wildcard characters:True ...
TheWHEREclause, if given, indicates the condition or conditions that rows must satisfy to be selected.where_conditionis an expression that evaluates to true for each row to be selected. The statement selects all rows if there is noWHEREclause. ...
TheWHEREclause, if given, indicates the condition or conditions that rows must satisfy to be selected.where_conditionis an expression that evaluates to true for each row to be selected. The statement selects all rows if there is noWHEREclause. ...