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Oracle PL - SQL Interview Questions

Q   |   QA

PL/SQL uses block structure as its basic structure. Anonymous blocks or nested blocks can be used in PL/SQL.

A set of related declarations and procedural statements is called block.

DECLARE -- declaration section BEGIN -- executable statements -- main section EXCEPTION -- handling possible exceptions -- occuring in the main section END; 

Some scalar data types such as

  • NUMBER,
  • VARCHAR2,
  • DATE,
  • CHAR,
  • LONG,
  • BOOLEAN.

Some composite data types such as RECORD & TABLE. 

% TYPE provides the data type of a variable or a database column to that variable.
% ROWTYPE provides the record type that represents a entire row of a table or view or columns selected in the cursor.
The advantages are : I. Need not know about variable's data type
ii. If the database definition of a column in a table changes, the data type of a variable changes accordingly. 

% ROWTYPE is to be used whenever query returns a entire row of a table or view.
TYPE rec RECORD is to be used whenever query returns columns of different
table or views and variables.
E.g. TYPE r_emp is RECORD (eno emp.empno% type,ename emp ename %type
);
e_rec emp% ROWTYPE
cursor c1 is select empno,deptno from emp;
e_rec c1 %ROWTYPE.

One more point : When we have a variable of typer RECORD we have declare additional variables but with %rowtype, we can only have the fields that are present in the table 

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