ISRO CSE 2009 | Question: 69

Question

The 'command' used to change contents of one database using the contents of another database by linking them on a common key field?

• A. Replace
• B. Join
• C. Change
• D. Update

Comments

Please confirm the answer for this question. I think answer should be update.

Refer: https://www.javatpoint.com/sql-update-with-join

Answer 1

ans is (b)

join clause combines columns from one or more tables in a relationaldatabase. It creates a set that can be saved as a table or used as it is. A JOIN is a means for combining columns from one (self-table) or more tables by using values common to each.

Comments

Why update cant be the answer as we change the contents of the table with this command only with the help of join command. Please explain.

Answer 2

Answer is B 

Replace command in sql :  Replaces all occurrences of a specified string value with another string value

Change : I don't think any command in db is there with Change key word

Update : Update a record in table

Answer 3

I guess the answer is b)join .

But join does not change the contents of the database

Comments

Agree..

Answer 4

D. Update     Consider a situation: A table named as USER_DATA is there which contains user details. This table has one column(along with other columns) named as  IS_ACTIVE which contain ‘0’ for a user, when a user will be in-active. One other table is there named as BLOG_DETAILS which contains columns asAUTHOR_ID, IS_ACTIVE and other column to keep blog details. Now if we want to run a script which should make column IS_ACTIVE = 0 in theBLOG_DATA table for in-active users. Here, we need a sql script which will containUPDATE with JOIN.   BLOG_DETAILS->AUTHOR_ID is foreign key which refers to the primary key USER_DATA->USER_ID

We can write the following query   UPDATE BLOG_DETAILS SET IS_ACTIVE = 0 FROM BLOG_DETAILS BD INNER JOIN USER_DATA UD ON UD.USER_ID = BD.AUTHOR_ID AND UD.IS_ACTIVE = 0   and we are done…