What is the max size of VARCHAR2 in PL/SQL and SQL?

Question

I am on Oracle 10g. In a requirement I need to increase the size of a pl/sql VARCHAR2 variable. It is already at 4000 size. I have read that

in PL/SQL, VARCHAR2 can be up to 32767 bytes. For SQL the limit is 4000 bytes

Can I increase the size of this variable without worrying about the SQL limit?

Solution 1

See the official documentation (http://docs.oracle.com/cd/B19306_01/server.102/b14200/sql_elements001.htm#i54330)

Variable-length character string having maximum length size bytes or characters. Maximum size is 4000 bytes or characters, and minimum is 1 byte or 1 character. You must specify size for VARCHAR2. BYTE indicates that the column will have byte length semantics; CHAR indicates that the column will have character semantics.

But in Oracle Databast 12c maybe 32767 (http://docs.oracle.com/database/121/SQLRF/sql_elements001.htm#SQLRF30020)

Variable-length character string having maximum length size bytes or characters. You must specify size for VARCHAR2. Minimum size is 1 byte or 1 character. Maximum size is: 32767 bytes or characters if MAX_STRING_SIZE = EXTENDED 4000 bytes or characters if MAX_STRING_SIZE = STANDARD

Solution 2

If you use UTF-8 encoding then one character can takes a various number of bytes (2 - 4). For PL/SQL the varchar2 limit is 32767 bytes, not characters. See how I increase a PL/SQL varchar2 variable of the 4000 character size:

SQL> set serveroutput on
SQL> l
  1  declare
  2    l_var varchar2(30000);
  3  begin
  4    l_var := rpad('A', 4000);
  5    dbms_output.put_line(length(l_var));
  6    l_var := l_var || rpad('B', 10000);
  7    dbms_output.put_line(length(l_var));
  8* end;
SQL> /
4000
14000

PL/SQL procedure successfully completed.

But you can't insert into your table the value of such variable:

SQL> ed
Wrote file afiedt.buf

  1  create table ttt (
  2    col1 varchar2(2000 char)
  3* )
SQL> /

Table created.

SQL> ed
Wrote file afiedt.buf

  1  declare
  2    l_var varchar2(30000);
  3  begin
  4      l_var := rpad('A', 4000);
  5      dbms_output.put_line(length(l_var));
  6      l_var := l_var || rpad('B', 10000);
  7      dbms_output.put_line(length(l_var));
  8      insert into ttt values (l_var);
  9* end;
SQL> /
4000
14000
declare
*
ERROR at line 1:
ORA-01461: can bind a LONG value only for insert into a LONG column
ORA-06512: at line 8

As a solution, you can try to split this variable's value into several parts (SUBSTR) and store them separately.

Solution 3

As per official documentation link shared by Andre Kirpitch, Oracle 10g gives a maximum size of 4000 bytes or characters for varchar2. If you are using a higher version of oracle (for example Oracle 12c), you can get a maximum size upto 32767 bytes or characters for varchar2. To utilize the extended datatype feature of oracle 12, you need to start oracle in upgrade mode. Follow the below steps in command prompt:

1) Login as sysdba (sqlplus / as sysdba)

2) SHUTDOWN IMMEDIATE;

3) STARTUP UPGRADE;

4) ALTER SYSTEM SET max_string_size=extended;

5) Oracle\product\12.1.0.2\rdbms\admin\utl32k.sql

6) SHUTDOWN IMMEDIATE;

7) STARTUP;

Solution 4

Not sure what you meant with "Can I increase the size of this variable without worrying about the SQL limit?". As long you do not try to insert a more than 4000 VARCHAR2 into a VARCHAR2 SQL column there is nothing to worry about.

Here is the exact reference (this is 11g but true also for 10g)

http://docs.oracle.com/cd/E11882_01/appdev.112/e17126/datatypes.htm

VARCHAR2 Maximum Size in PL/SQL: 32,767 bytes Maximum Size in SQL 4,000 bytes

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Comments

[Jing He]

wait... what's the difference between PL/SQL and SQL... I thought every SQL used in Oracle is called PL/SQL....

[zb226]

To quote wikipedia: PL/SQL (Procedural Language for SQL) is Oracle Corporation's procedural extension for SQL and the Oracle relational database.