Oracle Database 11g Release 1 introduced a new feature called OLTP Table Compression that allows data to be compressed during all types of data manipulation operations, including conventional DML such as INSERT and UPDATE. In addition, OLTP Table Compression reduces the associated compression overhead of write operations making it suitable for transactional or OLTP environments as well. OLTP Table Compression, therefore, extends the benefits of compression to all application workloads. It should be noted that Basic Table Compression is a base feature of Oracle Database 11g Enterprise Edition (EE).
OLTP Table Compression is part of the Oracle Advanced Compression option, which requires a license in addition to the Enterprise Edition.