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Which three statements are true about views in an Oracle Database?

2020.2.1 071 98

(关于Oracle数据库中的视图,以下哪三个陈述是正确的?)

A SELECT statement cannot contain a WHERE clause when querying a view containing a WHERE clause in its defining query(当查询在其定义查询中包含WHERE子句的视图时,SELECT语句不能包含WHERE子句)

B Rows inserted into a table using a view are retained in the table if the view is dropped. (如果删除视图,则使用视图插入到表中的行将保留在表中。)

C Views can join tables only if they belong to the same schema. (视图仅在属于同一模式时才可以联接表。)

D Views have no segment. (视图没有分割。)

E Views have no object number(视图没有对象编号)

F A view can be created that refers to a non-existent table in its defining query. clause in its defining query.(可以创建一个在其定义查询中引用不存在的表的视图。定义查询中的子句)

答案:BCD

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