What Is the Process Chain?

The process chain is a description of how information is processed from the time you request data through a Lawson application until the point when the information is returned to you.

The chain begins when you start a Lawson application. The program sends a message to ladb, which then determines the kind of database for each of the tables used by that program. If ladb encounters any IBM DB2 table, ladb starts a process to manage the information requests from that program.

When you ask the application program to process information, the program sends a message, known as a database call, to the database driver. The database call consists of some or all of the following:

• Identification and security information.

• The database command (FIND, STORE, DELETE, and so on).

• The product line and table to use.

• Key columns to find the data.

• Data to insert or update.

• Needed columns.

• The preferred index.

The database driver builds a SQL statement to send the database call to the IBM DB2 database server. This server processes the call by checking the appropriate database tables and then sending your data (or an error message if something goes wrong) back through the database driver to your application program.