Derive new fields from existing fields

Fields in a logical file can be derived from fields in the 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
  Using the CONCAT keyword, you can combine two or more fields from a physical file record format to make one field in a logical file record format.
• Substring fields
  You can use the SST keyword to specify which fields (character, hexadecimal, or zoned decimal) are in a substring. You can also use substring with a packed field in a physical file by specifying S (zoned decimal) as the data type in the logical file.
• Renamed fields
  You can name a field in a logical file differently than in a physical file using the RENAME keyword. You might want to rename a field in a logical file because the program was written using a different field name or because the original field name does not conform to the naming restrictions of your high-level language.
• Translated fields
  You can specify a translation table for a field using the TRNTBL keyword. When you read a logical file record and a translation table was specified for one or more fields in the logical file, the system translates the data from the field value in the physical file to the value determined by the translation table.