Understanding the Distinction between Datetime and Timestamp in SQL Server

While both Datetime and Timestamp data types in SQL Server handle dates and times, they exhibit a fundamental difference.

Datetime is a data type specifically designed for storing date and time information. It supports a wide range of formats and date/time calculations. On the other hand, Timestamp is not intended to store date and time values but rather serves as a rowversion data type.

Rowversion vs. Datetime

Rowversion is a unique value automatically generated by SQL Server to track changes to a row. When a row is modified or inserted, the rowversion value associated with that row is incremented. By leveraging rowversion, SQL Server can efficiently detect and manage data changes within a database.

Timestamp is an alias for rowversion, meaning it inherits the same properties. It is primarily used in concurrency control and versioning scenarios, where it guarantees that each row has a unique identity.

Key Distinctions

• Purpose: Datetime is used for storing date and time data, while Timestamp (rowversion) is used for managing row-level concurrency.
• Generation: Datetime values can be explicitly set or derived from input data, while Timestamp values are automatically generated and incremented by SQL Server.
• Constraints: Datetime values can be constrained to ensure data integrity, whereas Timestamp values are constrained to be unique for each row within a table.

In summary, Datetime and Timestamp in SQL Server serve distinct roles. Datetime is a general-purpose data type for representing dates and times, while Timestamp (rowversion) is optimized for managing row-level concurrency and versioning.