LONG Datatype in Oracle

•Before going into detail oracle strongly recommend not to use LONG datatype in oracle. LONG datatype is remained for backward compatibility. If you have LONG datatype in your database then convert it to LOB data type using TO_LOB function which is discussed on How to Convert LOB .

•LONG datatype store variable-length character strings containing up to 2 gigabytes -1, or power(2,31)-1 bytes.

The use of LONG datatype is subject to the following restriction.

•A table can contain only one LONG column.

•You cannot create an object type with a LONG attribute.

•LONG columns cannot appear in WHERE clauses or in integrity constraints (except that they can appear in NULL and NOT NULL constraints).

Details are in http://arjudba.blogspot.com/2008/06/long-datatype-in-oracle.html