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Oracle deadlocks: the what and the how
Everyone knows what a deadlock is: a situation in which two or more competing processes are waiting for the other to finish, and thus neither ever does. The purpose of this post is to help people understanding the deadlock a little better with a view to enable them to fix the problem when they find [...]
When NOT to normalise the database
When talking of Database Normalisation, textbooks often talk of BCNF, fifth and higher normal forms. However, in practice (in large software/ERPs) I have rarely noticed normalisation beyond Third Normal form. In fact, there is a certain degree of redundancy that is desirable. While doing database design, I believe there are two critical aspects that should [...]
Generating sequential numbers in a database
You are creating an application that allows organisations to manage employees. One of the tasks that it has to do is generate an employee ID when a new employee is being entered. One way of doing this is through this query: SELECT max(empl_id)+1 FROM employee; However, this query presents a problem in a multiuser environment: [...]
Performance tuning SQL queries in Oracle
Video tutorial showing how to optimise your SQL queries for maximum performance. Talks about indexes, statistics, hints and optimiser plans.
