Understanding bind variable types : Binded variable « PL SQL Statements « Oracle PL/SQL Tutorial

1. Oracle PL/SQL Tutorial
2. PL SQL Statements
3. Binded variable

Bind variables can be of type IN, OUT, or IN OUT.

By default, all parameters are of type IN.

Using an OUT Parameter

SQL> declare
  2     a NUMBER;
  3     b NUMBER:=1;
  4     c NUMBER:=2;
  5     v_plsql_tx VARCHAR2(2000);
  6  begin
  7      v_plsql_tx := 'begin ' || ':1:=:2 -:3; ' || 'end;';
  8      execute immediate v_plsql_tx using out a, b, c;
  9      DBMS_OUTPUT.put_line('a='||a);
 10  end;
 11  /
a=-1

PL/SQL procedure successfully completed.

SQL>