Deriving new fields from existing fields

 

Fields in a logical file can be derived from fields in a physical file on which the logical file is based or from fields in the same logical file.

For example, you can concatenate, using the CONCAT keyword, two or more fields from a physical file to make them appear as one field in the logical file. Likewise, you can divide one field in the physical file to make it appear as multiple fields in the logical file with the SST keyword.

• Concatenated fields
  You can use the Concatenate (CONCAT) DDS keyword to combine two or more fields from a physical file record format into one field in a logical file record format.

• Substring fields
  You can use the Substring (SST) DDS keyword to specify which fields (character, hexadecimal, or zoned decimal) are in a substring.

• Renamed fields
  You can use the Rename (RENAME) DDS keyword to name a field in a logical file differently than in a physical file.

• Translated fields
  You can use the Translation Table (TRNTBL) DDS keyword to specify a translation table for a field in a logical file.

 

Parent topic:

Describing logical file record formats