单项选择题
Which statement is true regarding Flashback Version Query？ （）
A. It returns versions of rows only within a transaction.
B. It can be used in subqueries contained only in a SELECT statement.
C. It will return an error if the undo retention time is less than the lower bound time or SCN specified.
D. It retrieves all versions including the deleted as well as subsequently reinserted versions of the rows.
相关考题
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单项选择题
Evaluate the following statement： Which statement is true regarding the evaluation of rows returned by the subquery in the INSERT statement？（）
A. They are evaluated by all the three WHEN clauses regardless of the results of the evaluation of any other WHEN clause.
B. They are evaluated by the first WHEN clause. If the condition is true， then the row would be evaluated by the subsequent WHEN clauses.
C. They are evaluated by the first WHEN clause. If the condition is false， then the row would be evaluated by the subsequent WHEN clauses.
D. The INSERT statement would give an error because the ELSE clause is not present for support in case none of the WHEN clauses are true. -
单项选择题
EMPDET is an external table containing the columns EMPNO and ENAME. Which command would work in relation to the EMPDET table？（）
A.A
B.B
C.C
D.D -
多项选择题
WhichthreepossiblevaluescanbesetfortheTIME_ZONEsessionparameterbyusingtheALTERSESSIONcommand？（）
A. os
B. local
C. -8：00
D. dbtimezone Li
E. Australia
