Which query is valid? 

Why would you use the TNSPING hr command?

What is the effect on new transactions when all undo space in the default undo tablespace is in use by active transactions?

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SALES2 is a table with the same description as SALES1.
Some sales data is contained erroneously in both tables.
You must display rows from SALES1 and SALES2 and wish to see the duplicates too.
Which set operator generates the required output?

CREATE TABLE alter_test ( c1 VARCHAR2 ( 10), c2 NUMBER( 10)) ; INSERT INTO alter_test VALUES ('123', 123) ; 

COMMIT ; 

Which is true about modifying the columns in ALTER_TEST?

1. A connection must be terminated after four unsuccessful login attempts by user.

2. A user should not be able to create more than four simultaneous sessions.

3. User session must be terminated after 15 minutes of inactivity.

4. Users must be prompted to change their passwords every 15 days.

How would you accomplish these requirements?

Examine the description of the PRODUCTS table: 

Name                   Null                      Type

PROD_ID          NOT NULL             NUMBER 

PROD_NAME                               VARCHAR2 (40) 

COST                                            NUMBER(8,2)

RELEASE_DATE                                 DATE

Which query is valid?

Examine this statement:

SELECT 1 AS id, 'John' AS first_name, NULL AS commission

FROM DUAL

INTERSECT

SELECT 1, 'John' ,NULL

FROM DUAL

ORDER BY 3;

What is returned upon execution?

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SALES2 is a table with the same description as SALES1.
Some sales data is duplicated in both tables.
You want to display the rows from the SALES1 table which are not present in the SALES2 table.
Which set operator generates the required output?