The term CLOB stands for character large object. This topic describes how to use the CLOB data type and provides an example to show you how to create a CLOB column.
Considerations
CLOBs are used to store single-byte and multi-byte character data. CLOBs support fixed-width and variable-width character sets. These character sets both use the database character set. A CLOB can store up to 536,870,910 bytes of data, and uses the same character set as the tenant.
A field of the VARCHAR2 data type can store a maximum of 32,767 bytes of data. To store a field with a length greater than 32,767 bytes, you can convert the field to the CLOB data type. You can also use CLOBs to store CHAR data. For example, you can use CLOBs to store XML documents.
CLOBs have full transactional support. Changes made by using SQL statements and the DBMS_LOB package participate in the transaction. Therefore, changes to CLOB values can be committed and rolled back. However, you cannot save a CLOB locator in a PL variable in one transaction and then use it in another transaction or session.
Examples
Execute the following statement to create a table named clob_tbl and set the data type of the clob_col column to CLOB.
obclient> CREATE TABLE clob_tbl (clob_col CLOB);
Query OK, 0 rows affected