Pl/sql Learning Notes (i)

Notes
The data types in Pl/sql are listed below:



number[(m,n)] unique numeric type. M-precision, n-decimal digit number. INTEGER, Real is the synonym definition of number.



VARCHAR2 (maxsize[char| BYTE]) is a unique string type. CHAR, Vachar is defined as a synonym for VARCHAR2. NVARCHAR2, like VARCHAR2, is used for international character set data types only.



Date/Time type.



A Boolean type. Only true, false two values.



Ii. Executive Body of Pl/sql



DECLARE



--Variable declaration



BEGIN



--Run the statement



EXCEPTION



--Exception handling



End;



Three, PL/SQL control structure



1. If-then-elsif structure



IF condition THEN



elsif conditions THEN



End IF;



2. Case structure



Case



When condition THEN

When condition THEN



...



ELSE if all conditions are not satisfied



End;



IV. circular structure (see example)



Declarei INTEGER; BEGIN



Dbms_output. Put_Line (' LOOP OUTPUT '); i:=0; Loopexit when I>=10;dbms_output. Put_Line (i); i:=i+1; End Loop;dbms_output. Put_Line (' while OUTPUT '); i:=0; While I<10 Loopdbms_output. Put_Line (i); i:=i+1; End Loop;dbms_output. Put_Line (' for OUTPUT '); For I in 1..10 loopdbms_output. Put_Line (i); End LOOP;



EXCEPTION when others THEN dbms_output. Put_Line (' EXCEPTION '); RAISE; end;/