40.Evaluate the following code:
SQL>VARIABLE task_name VARCHAR2(255);
SQL>VARIABLE sql_stmt VARCHAR2(4000);
SQL>BEGIN :sql_stmt := 'SELECT COUNT(*) FROM customers WHERE cust_state_province =''CA''';
:task_name := 'MY_QUICKTUNE_TASK';
DBMS_ADVISOR.QUICK_TUNE(DBMS_ADVISOR.SQLACCESS_ADVISOR,
:task_name, :sql_stmt);
END;
What is the outcome of this block of code?
A. It creates a task and workload, and executes the task.
B. It creates a task and workload but does not execute the task.
C. It produces an error because a template has not been created.
D. It produces an error because the SQL Tuning Set has not been created.
Answer: A
答案解析:
参考:http://docs.oracle.com/cd/E11882_01/server.112/e41573/advisor.htm#PFGRF94911
Performing a Quick Tune
To tune a single SQL statement, the QUICK_TUNE procedure accepts as its input a task_name and a SQL statement. The procedure creates a task and workload and executesthis task. There is no difference in the results from using QUICK_TUNE. They are exactly the same as those from using EXECUTE_TASK,but this approach is easier to use when there is only a single SQL statement to be tuned. The syntax is as follows:
DBMS_ADVISOR.QUICK_TUNE ( advisor_name IN VARCHAR2, task_name IN VARCHAR2, attr1 IN CLOB, attr2 IN VARCHAR2 := NULL, attr3 IN NUMBER := NULL, task_or_template IN VARCHAR2 := NULL);The following example shows how to quick tune a single SQL statement: VARIABLE task_name VARCHAR2(255);VARIABLE sql_stmt VARCHAR2(4000);EXECUTE :sql_stmt := 'SELECT COUNT(*) FROM customers WHERE cust_state_province =''CA''';EXECUTE :task_name := 'MY_QUICKTUNE_TASK';EXECUTE DBMS_ADVISOR.QUICK_TUNE(DBMS_ADVISOR.SQLACCESS_ADVISOR, :task_name, :sql_stmt);
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