Remembering Web-Server Programming in Apache
Before the World Wide Web appeared, client/server network programming was a drag. Application developers had to develop the communications protocol, write the low-level network code to reliably transmit and receive messages, create a user interface at the client side of the connection, and write a server to listen for incoming requests, service them properly, and [...]
Declarative and Procedural Integrity: Violation Responses
Violation Responses When defining the database schema, you must not only determine how a given integrity constraint might most effectively be implemented, you must also decide what action the database engine should take if the constraint is violated. In most cases, of course, the database will simply reject the offending command, posting an error in [...]
Implementing Data Integrity
In this blog post, we’ll look at a few of the issues involved in creating the physical model of the problem space: the database schema. Moving from one level to another is primarily a change in terminology—relations become tables and attributes become fields—except for issues of data integrity. These never map quite as cleanly as [...]
Using Software to Save Time in Doing Business
Time is money, business gurus would say. Unwise use of time would have unfavorable financial consequences. It could mean loss of profit. It could mean loss of new business opportunities. By all means, strategic ways of using time would have a long positive impact on business operation. I am saying this because I still find [...]
What is Database Integrity
Database Integrity The most general form of integrity constraint is the database constraint. Database constraints reference more than one relation: “A Customer is not allowed to have a status of ‘Preferred’ unless he or she has made a purchase in the last 12 months.” The majority of database constraints take this form. It’s always a [...]