Migrating LONG to LOBs

The database applications using LONG data types should migrate to LOB due to the following reasons:

• A LONG column can store a maximum of (2GB - 1) while an LOB can store a maximum data of (4GB - 1)

• A table can have one, and only one, LONG data type column while there is no restriction on the number of LOB columns in a table

• Data replication is not allowed with the LONG and LONG RAW columns

Tip

Migrating LONG to the LOB columns may generate a lot of redo. Therefore, it is advised to switch off the logging for the table containing the LONG column.

You can convert LONG to CLOB and LONG RAW to BLOB using either of the following listed approaches:

Use the ALTER TABLE command

For a table with the LONG type column, you can use the ALTER TABLE command to modify the column type to LOB with new storage specifications and migrate the data to a new space. Note that all the LONG data is migrated as LOB in the table. All the column-level characteristics of the LONG column are retained and...