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Question 36 :

How will you delete duplicating rows from a base table?

Answer :

delete from table_name where rowid not in (select max(rowid) from table group by duplicate_values_field_name); or delete duplicate_values_field_name dv from table_name ta where rowid <(select min(rowid) from table_name tb where ta.dv=tb.dv);


Question 37 :

Difference between database triggers and form triggers?

Answer :

-Data base trigger(DBT) fires when a DML operation is performed on a data base table. Form trigger(FT) Fires when user presses a key or navigates between fields on the screen
-Can be row level or statement level No distinction between row level and statement level.
-Can manipulate data stored in Oracle tables via SQL Can manipulate data in Oracle tables as well as variables in forms.
-Can be fired from any session executing the triggering DML statements. Can be fired only from the form that define the trigger.
-Can cause other database triggers to fire. Can cause other database triggers to fire, but not other form triggers.


Question 38 :

What is a cursor for loop?

Answer :

Cursor For Loop is a loop where oracle implicitly declares a loop variable, the loop index that of the same record type as the cursor's record.


Question 39 :

How you will avoid duplicating records in a query?

Answer :

By using DISTINCT


Question 40 :

What is a view ?

Answer :

A view is stored procedure based on one or more tables, it's a virtual table.