Oracle Certification Exam – Page 3 – Orace Locking and Latching

TX (Transaction) Locks- Locking and Latching-3

However, before we can say that we have a good understanding of how the row locking in Oracle works, we must look at one last…

It was during a benchmark that I discovered just how wrong I was. In the early days of these databases, it was common for the…

This is a simple implementation that involves adding a single column to each database table you wish to protect from lost updates. This column is…

Exactly the same issue affected concurrent updates (since an UPDATE was really a DELETE followed by an INSERT in SQL Server). Perhaps this is why…

This is very similar to the previous version column method, but it uses the base data itself to compute a “virtual” version column. I’ll quote…

Locks are mechanisms used to regulate concurrent access to a shared resource. Note how I used the term “shared resource” and not “database row.” It…

Before we discuss the various types of locks that Oracle uses, it is useful to look at some locking issues, many of which arise from…

The second method, referred to as optimistic locking, defers all locking up to the point right before the update is performed. In other words, we…

The pessimistic locking method would be put into action the instant before a user modifies a value on the screen. For example, a row lock…