File processing options

 

DB2 Universal Database™ for iSeries™ provides several runtime file processing options.

• Specifying the type of processing
  When you use a database file in a program, the system needs to know what type of operation you plan to use for the file. You can specify the type of processing with the OPTION parameter.

• Specifying the initial file position
  After a database file is opened, the system needs to know where it should start processing the file. You can specify the initial file position with the POSITION parameter.

• Reusing deleted records
  Sometimes you might want to reuse deleted records for your database files. In this case, you can use the REUSEDLT parameter.

• Ignoring the keyed sequence access path
  If a key field is defined for a database file, the system automatically uses the keyed sequence access path. However, sometimes you can use the ACCPTH parameter to ignore the keyed sequence access path for better performance.

• Delaying end-of-file processing
  When your program reaches the end of a database file, the system normally signals your program that there is no more data to read. If you want the system to hold your program until more data arrives in the file, use the EOFDLY parameter to delay the end-of-file processing.

• Specifying the record length
  As an option, you can specify the record length in your high-level language program.

• Ignoring record formats
  When you use a multiple-format logical file, the system assumes that you want to use all the formats defined for the file. However, if you do not want to use all the formats, you can specify which formats you want to use and ignore.

• Determining whether duplicate keys exist
  The set of keyed sequence access paths used to determine whether the key is a duplicate key differs depending on the input/output (I/O) operation that is performed. You can determine whether duplicate keys exist using the DUPKEYCHK parameter.

 

Parent topic:

Database file processing: Runtime considerations