Oracle PL/SQL Variables
There are 3-type of variables can be usedin sqlplus.
- Define variable and bind variableare sqlplus variable, they are valid during a sqlplus session.
- Declare variable are PL/SQLblock variable.
1. Define variable
Works like C/C++ language #define micro; there is in fact, astring replacement operation when a define variable is used; so its value can onlybe a string value.
l List all define variable
SQL>define
DEFINE_DATE = "2015/06/10"(CHAR)
DEFINE_CONNECT_IDENTIFIER = "batch006" (CHAR)
DEFINE_USER = "SCOTT"(CHAR)
DEFINE_PRIVILEGE = "" (CHAR)
DEFINE_SQLPLUS_RELEASE = "1102000100" (CHAR)
DEFINE_EDITOR = "ed" (CHAR)
DEFINE_O_VERSION = "Oracle Database11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production With thePartitioning, OLAP, Data Mining and Real Application Testing options"(CHAR)
DEFINE _O_RELEASE = "1102000100" (CHAR)
l Add a define variable
SQL> define MYDEF=ABC
SQL> define
DEFINE_DATE = "2015/06/10"(CHAR)
DEFINE_CONNECT_IDENTIFIER = "batch006" (CHAR)
DEFINE_USER = "SCOTT"(CHAR)
DEFINE_PRIVILEGE = "" (CHAR)
DEFINE_SQLPLUS_RELEASE = "1102000100" (CHAR)
DEFINE_EDITOR = "ed" (CHAR)
DEFINE_O_VERSION = "Oracle Database11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With thePartitioning, OLAP, Data Mining and Real Application Testing options"(CHAR)
DEFINE_O_RELEASE = "1102000100"(CHAR)
DEFINE MYDEF = "ABC" (CHAR)
l Check a given define variable
SQL> define MYDEF
DEFINE MYDEF = "ABC" (CHAR)
l Remove a define variable
SQL> undefine MYDEF
SQL> define MYDEF
SP2-0135: symbol mydef is UNDEFINED
l Use a define variable in sqlplus
SQL> select '&MYDEF'from dual; #use a ‘&’ to refer a define variable
old 1: select'&MYDEF' from dual
new 1: select'ABC' from dual
'ABC'
---------
ABC
l Use a define variable in block
SQL> declare
2 xvarchar2(10);
3 begin
4 select '&MYDEF' into x from dual;
5 end;
6 /
old 4: select '&MYDEF'into x from dual;
new 4: select'ABC' into x from dual;
PL/SQL procedure successfully completed.
2. Bind variable, i.e,. hostvariable
l List all bind variable
SQL> print
SP2-0568: No bind variables declared.
l Add a bind variable
SQL> var MYBIND varchar2(10);
SQL> print
MYBIND
--------------------------------------------------------------------------------
l List a single bind variable
SQL> exec :MYBIND := to_char(sysdate); # use a ':' to refer a bind variable
PL/SQL procedure successfully completed.
SQL> print MYBIND
MYBIND
--------------------------------------------------------------------------------
2015/06/11
l Assign a bind variable
SQL> execute :MYBIND := 'aaa';
PL/SQL procedure successfully completed.
l Assign a bind variable in block
SQL> begin
2 :MYBIND:='bbb';
3 end;
4 /
PL/SQL procedure successfully completed.
l Use a bind variable
SQL> select :MYBIND VAR from dual;
VAR
--------------------------------------------------------------------------------
bbb
l Use a bind variable in block
SQL> declare
2 x varchar2(10);
3 begin
4 select :MYBIND into x from dual;
5 end;
6 /
PL/SQL procedure successfully completed.
l The end
3. Declare variable
Declare variableis a block variable, or parameter variable.
SQL> SETSERVEROUTPUT ON;
SQL> declare
2 xvarchar2(10);
3 begin
4 x :='abcd';
5 select 'AAAA' into x from dual where x = 'abcd';
6 DBMS_OUTPUT.PUT_LINE(x);
7 end;
8 /
AAAA
PL/SQL proceduresuccessfully completed.