Hey there SQL MASTERS, here are some questions i was posed in an interview/assessment thing, dunno how well i did....Coud u answer these questions? i dont know how easy/difficut they are for u, all i know is that i had SERIOUS trouble with them! thanks alot!EMPLOYEEEmployee_id number NOT NULL (Primary Key)Employee_name VarChar(30) NOT NULL Dept_id number NOT NULL (Foreign Key to DEPARTMENT)Manager_id number NOT NULL (Foreign Key to EMPLOYMENT)Salary number
1. why the performance of the table is degraded when more index is created on the table......2. whats the main usage of synonym other than that of creating other names to objects....3. shall we able to create an primary index on the table which already has the null value? if yes syntax please.........4. whats the main usage of trigger.......... (eg..) please...
Select comm from emp; The Null column in the output will come in the last i.e at the end. WHY?e.g COMM 1200 1000 1300 1450 ---- (NULL) ---- (NULL)
Consider that we r having table name emp....now the question is 1.how should we print the odd rows from that table?2.how should we print the rows where comm=NULL.Reply ASAP
I think there can be only one null value for a unique key constraint but some say there can be more than one null value.
Latest Answer : Can have any number of NULL values, since oracle maintains internally different values for each NULL values. ...
Latest Answer : NVL is a built in function provided by oracle which accepts two parameters. NVL function returns the first parameter if the first parameter is not null and it returns the second parameter if the first parameter is null.select emp_no, nvl(comm_prt,0) ...
Latest Answer : NOT NULL: It allows duplicates, but doesn't allow null valuesUNIQUE: It allows null values, but doesn't allow duplicatesPRIMARY KEY: It doesn't allows duplicates and null valuesUnique index wil be created automatically for PRIMARY KEY, ...
I cant drop the whole column because that is interlinked with my process? I have declared not null on a column, I have to change it
Latest Answer : Dear Sarika,Instead dropping the constraint just disable the constarint.The command is:Alter table table_name disable constraint constraint_name;try it and reply me ...
How to handle Null value in WHERE Condition?
