EMPTY_BLOB and EMPTY_CLOB return an empty LOB locator that can be used to initialize a LOB variable or, in an INSERT or UPDATE statement, to initialize a LOB column or attribute to EMPTY. EMPTY means that the LOB is initialized, but not populated with data.


An empty LOB is not the same as a null LOB, and an empty CLOB is not the same as a LOB containing a string of 0 length. For more information, see Oracle Database SecureFiles and Large Objects Developer's Guide.

See Also:

Appendix C in Oracle Database Globalization Support Guide for the collation derivation rules, which define the collation assigned to the return value of EMPTY_CLOB

Restriction on LOB Locators

You cannot use the locator returned from this function as a parameter to the DBMS_LOB package or the OCI.


The following example initializes the ad_photo column of the sample pm.print_media table to EMPTY:

UPDATE print_media
  SET ad_photo = EMPTY_BLOB();