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单选题
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.


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考题 单选题You are employed as a DBA in an organization. You are informed that the record of EMP_NO 1000 is missing from the SCOTT.EMP table. You are required to identify the user who deleted the record, the SQL statement that will undo the deletion, and the transaction ID of the transaction that deleted the employee record. Which feature will you use to perform the tasks?()A  Only the Flashback TableB  Both the Flashback Transaction Query and the Flashback Version QueryC  Only the Flashback DropD  Only the Flashback Version

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考题 多选题Which two statements regarding the FLASHBACK_TRANSACTION_QUERY view are correct?()AYou can find information about only active transactions from the viewBYou can find information about read only transactions from the viewCYou require the SELECT ANY TRANSACTION system privilege to access the viewDYou can find information about both active and committed transactions from the viewEYou require the SELECT ON FLASHBACK_TRANSACTION_QUERY object privilege to access the view

考题 多选题Which two statements are true about WHERE and HAVING clauses? ()AA WHERE clause can be used to restrict both rows and groups.BA WHERE clause can be used to restrict rows only.CA HAVING clause can be used to restrict both rows and groups.DA HAVING clause can be used to restrict groups only.EA WHERE clause CANNOT be used in a query of the query uses a HAVING clause.FA HAVING clause CANNOT be used in subqueries.

考题 单选题You executed the following query: SELECT operation, undo_sql, table_name FROM flashback_transaction_query;  Which statement is correct regarding the query output?()A It would return information regarding only the last committed transaction.B It would return only the active transactions in all the undo segments in the database.C It would return only the committed transactions in all the undo segments in the database.D It would return both active and committed transactions in all the undo segments in the database.E It would return information regarding the transactions that began and were committed in the last 30 minutes.

考题 多选题Which two statements about subqueries are true? ()AA single row subquery can retrieve data from only one table.BA SQL query statement cannot display data from table B that is referred to in its subquery, unless table B is included in the main query's FROM clause.CA SQL query statement can display data from table B that is referred to in its subquery, without including B in its own FROM clause.DA single row subquery can retrieve data from more than one table.EA single row subquery cannot be used in a condition where the LIKE operator is used for comparison.FA multiple-row subquery cannot be used in an INSERT statement to insert multiple rows at a time.

考题 多选题Which two statements about subqueries are true? ()AA subquery should retrieve only one row.BA subquery can retrieve zero or more rows.CA subquery can be used only in SQL query statements.DSubqueries CANNOT be nested by more than two levels.EA subquery CANNOT be used in an SQL query statement that uses group functions.FWhen a subquery is used with an inequality comparison operator in the outer SQL statement, the column list in the SELECT clause of the subquery should contain only one column.

考题 单选题By mistake, you ran the batch job (for updating the BILL_DETAILS table) twice. You are not sure which rows in the BILL_DETAILS table were affected. You need to identify:  a) A list of changes made along with the transaction identifier of each change.  b) The necessary SQL statements to undo the erroneous changes.  Which option would you choose?()A  RMAN only.B  Flashback Table only.C  Flashback Version Query only.D  Flashback Database and Flashback Transaction Query.E  Flashback Version Query and Flashback Transaction Query.

考题 单选题What is true regarding subqueries?()A The inner query always sorts the results of the outer queryB The outer query always sorts the results of the inner queryC The outer query must return a value to the outer queryD The inner query returns a value to the outer queryE The inner query must always return a value or the outer query will give an error

考题 单选题You executed the following query:  SELECT operation, undo_sql, table_name FROM flashback_transaction_query; Which statement is correct regarding the query output?()A  It would return information regarding only the last committed transaction.B  It would return only the active transactions in all the undo segments in the database.C  It would return only the committed transactions in all the undo segments in the database.D  It would return both active and committed transactions in all the undo segments in the database.E  It would return information regarding the transactions that began and were committed in the last 30 minutes.