The chapters in this part include information on processing database files in your programs. This includes information on planning how the file will be used in the program or job and improving the performance of your program. Descriptions of the file processing parameters and run-time options that you can specify for more efficient file processing are included in this section.
Another topic covered in this part is sharing database files across jobs so that they can be accessed by many users at the same time. Locks on files, records, or members that can prevent them from being shared across jobs are also discussed.
Using the Open Query File (OPNQRYF) command and the Open Database File (OPNDBF) command to open database file members in a program is discussed. Examples, performance considerations, and guidelines to follow when writing a high-level language program are also included. Also, typical errors that can occur are discussed.
Finally, basic database file operations are discussed. This discussion includes setting a position in the database file, and reading, updating, adding, and deleting records in a database file. A description of several ways to read database records is also included. Information on updating discusses how to change an existing database record in a logical or physical file. Information on adding a new record to a physical database member using the write operation is included. This section also includes ways you can close a database file when your program completes processing a database file member, disconnecting your program from the file. Messages to monitor when handling database file errors in a program are also discussed.