create or replace procedure proc1(  
 p_para1 varchar2,  
 p_para2 out varchar2,  
 p_para3 in out varchar2  
)as  
 v_name varchar2(20);  
begin  
 v_name := '张三丰';  
 p_para3 := v_name;  
 dbms_output.put_line('p_para3:'||p_para3);  
end; 

create or replace procedure proc1(  
 p_para1 varchar2,  
 p_para2 out varchar2,  
 p_para3 in out varchar2  
)as  
 v_name varchar2(20);  
begin  
 p_para1 :='aaa';  
 p_para2 :='bbb';  
 v_name := '张三丰';  
 p_para3 := v_name;  
 dbms_output.put_line('p_para3:'||p_para3);  
 null;  
end;  
    
Warning: Procedure created with compilation errors  
 
SQL> show error;  
Errors for PROCEDURE LIFEMAN.PROC1:  
 
LINE/COL ERROR  
-------- ----------------------------------------------------------------------  
8/3   PLS-00363: expression 'P_PARA1' cannot be used as an assignment target  
8/3   PL/SQL: Statement ignored 

create or replace procedure proc1(  
 p_para1 varchar2,  
 p_para2 out varchar2,  
 p_para3 in out varchar2  
)as  
 v_name varchar2(20);  
begin  
 v_name := '张三丰';  
 p_para3 := v_name;  
 dbms_output.put_line('p_para1:'||p_para1);  
 dbms_output.put_line('p_para2:'||p_para2);  
 dbms_output.put_line('p_para3:'||p_para3);  
end;  
 
SQL> var p1 varchar2(10);  
SQL> var p2 varchar2(10);  
SQL> var p3 varchar2(10);  
SQL> exec :p1 :='aaaa';  
SQL> exec :p2 :='bbbb';  
SQL> exec :p3 :='cccc';  
SQL> exec proc1(:p1,:p2,:p3);  
p_para1:aaaa  
p_para2:  
p_para3:张三丰  
SQL> exec dbms_output.put_line(:p2);  
 
 
PL/SQL procedure successfully completed  
p2  
--------- 

create or replace procedure proc1(  
 p_para1 varchar2,  
 p_para2 out varchar2,  
 p_para3 in out varchar2  
)as  
 v_name varchar2(2);  
begin  
 v_name := p_para1;  
end;  
SQL> var p1 varchar2(10);  
SQL> var p2 varchar2(20);  
SQL> var p3 varchar2(30);  
SQL> exec :p1 :='aaaaaa';  
SQL> exec proc1(:p1,:p2,:p3);  
ORA-06502: PL/SQL: numeric or value error: character string buffer too small  
ORA-06512: at "LIFEMAN.PROC1", line 8 
ORA-06512: at line 1 

create or replace procedure proc1(  
 p_para1 varchar2,  
 p_para2 out varchar2,  
 p_para3 in out varchar2  
)as  
 v_name varchar2(2);  
begin  
 p_para2 :='aaaaaaaaaaaaaaaaaaaa';  
end;  
SQL> var p1 varchar2(1);  
SQL> var p2 varchar2(1);  
SQL> var p3 varchar2(1);  
SQL> exec :p2 :='a';  
SQL> exec proc1(:p1,:p2,:p3); 

SQL> select dump(:p2) from dual;  
DUMP(:P2)  
---------------------------------------------------------------------------  
Typ=1 Len=20: 97,97,97,97,97,97,97,97,97,97,97,97,97,97,97,97,97,97,97,97 
p2  
---------  
aaaaaaaaaaaaaaaaaaaa 

create or replace procedure proc1(  
 p_para1 varchar2,  
 p_para2 out varchar2,  
 p_para3 in out varchar2  
)as  
 v_name varchar2(2);  
begin  
 p_para3 :='aaaaaaaaaaaaaaaaaaaa';  
end;  
SQL> var p1 varchar2(1);  
SQL> var p2 varchar2(1);  
SQL> var p3 varchar2(1);  
SQL> exec proc1(:p1,:p2,:p3); 

create or replace procedure procdefault(p1 varchar2,  
                    p2 varchar2 default 'mark')  
as  
begin  
 dbms_output.put_line(p2);  
end;  
SQL> set serveroutput on;  
SQL> exec procdefault('a'); 
mark 

create or replace procedure procdefault2(p1 varchar2 default 'remark',  
                    p2 varchar2 )  
as  
begin  
 dbms_output.put_line(p1);  
end; 

exec procdefault2('aa'); 

SQL> exec procdefault2(p2 =>'aa'); 
remark 

Declare … begin … exception … end;  
create or replace procedure innerBlock(p1 varchar2)  
as  
 o1 varchar2(10) := 'out1';  
begin  
 dbms_output.put_line(o1);  
 declare  
  inner1 varchar2(20);  
 begin  
  inner1 :='inner1';  
  dbms_output.put_line(inner1);  
 
  declare  
   inner2 varchar2(20);  
  begin  
   inner2 := 'inner2';  
   dbms_output.put_line(inner2);  
  end;  
 exception  
  when others then  
   null;  
 end;  
end; 

type t_table is table of varchar2(20) index by binary_integer;  
 v_student t_table; 

type t_nestTable is table of varchar2(20);  
v_class t_nestTable ; 

v_class :=t_nestTable('a','b','c');