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Issue 8.3

COLUMN

Database Concurrency Strategies

Issue: 8.3 (March/April 2010)
Author Bio: Paul Lefebvre has been using REALbasic for 8 years and is the owner of LogicalVue Software, RBDevZone and a founding member of the Association of REALbasic Professionals.
Article Description: No description available.
Article Length (in bytes): 5,679
Starting Page Number: 53
Article Number: 8314
Related Link(s): None

Excerpt of article text...

If you are building multi-user database applications using REAL Studio, then you need to be aware of how to manage concurrency. There are two common ways that concurrency is managed and both have strengths and weaknesses. They are Pessimistic Concurrency Control and Optimistic Concurrency Control.

Pessimistic Concurrency Control

Pessimistic concurrency control is a very rigid way to manage database changes. Generally speaking, when a user requests to change some information in the database (usually a row), you set a database lock on the row. This lock prevents other users from being able to change the row. If another user tries to lock the rock, they will get an error. Once the first users commits their changes, the lock is released so that others may request it.

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