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What Are Locks?- Locking and Latching-2
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…
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Optimistic Locking Using a Checksum – Locking and Latching
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…
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What Are Locks?- Locking and Latching-1
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…
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Optimistic Locking – Locking and Latching
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…
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Pessimistic Locking – Locking and Latching
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…