Large Object (LOB) data can be lengthy enough that it makes sense to load it from a LOBFILE.

With LOBFILEs, LOB data instances are still considered to be in fields (predetermined size, delimited, length-value). However, these fields are not organized into records (the concept of a record does not exist within LOBFILEs). Therefore, the processing overhead of dealing with records is avoided. This type of organization of data is ideal for LOB loading.

For example, suppose you have a table that stores employee names, IDs, and their resumes. When loading this table, you can read the employee names and IDs from the main data files and you can read the resumes, which can be quite lengthy, from LOBFILEs.

You can also use LOBFILEs to facilitate the loading of XML data. You can use XML columns to hold data that models structured and semistructured data. Such data can be quite lengthy.

Secondary data files (SDFs) are similar in concept to primary data files. As with primary data files, SDFs are a collection of records, and each record is made up of fields. The SDFs are specified as needed for a control file field. Only a collection_fld_spec can name an SDF as its data source.

You specify SDFs by using the SDF parameter. You can enter a value for the SDF parameter either by using the file specification string, or by using a FILLER field that is mapped to a data field containing one or more file specification strings.