What is Sybase's 'timestamp' Datatype and How Does it Really Work?

Unveiling the Enigma of Sybase's 'Timestamp' Datatype

Sybase's "timestamp" datatype has sparked curiosity among developers. Despite its potential misconception, let's delve into its true nature and explore its functionality.

Definition and Attributes

"Timestamp" is essentially a varbinary(8) null datatype in Sybase, meaning it stores 8 bytes of arbitrary data.

Temporal Disconnect

Contrary to its name, the timestamp datatype does not directly correlate to time or date. The moniker is merely a semantic carryover from other database systems.

Immutability and Updates

Unique to the timestamp datatype is its automatic update upon row insertion or modification. However, there are two variations: TIMESTAMP, which updates on both insert and update, and CURRENT TIMESTAMP, which only updates on insert.

Purpose and Significance

Sybase's timestamp datatype primarily serves a role in optimistic concurrency control mechanisms. It provides a means to determine if a row has been modified since a transaction began, ensuring data integrity in a multi-user environment.

Alternatives and Considerations

While the timestamp datatype can serve its purpose in concurrency control, it is worth considering alternatives such as the datetime datatype, which explicitly represents temporal values and allows for direct comparison and manipulation.

Conclusion

Sybase's "timestamp" datatype, though deceiving in its name, proves to be a useful tool for implementing optimistic concurrency control mechanisms. It offers immutability and automatic updates to help ensure data integrity in multi-user systems. However, it is important to note its limitations and consider suitable alternatives when necessary.

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