Timestamp vs. Datetime in SQL Server
In SQL Server, both timestamp and datetime are data types designed to store date and time information. However, there are critical differences between the two:
Timestamp: Synonym for Rowversion
Contrary to the assumption that timestamps store date and time, a timestamp in SQL Server is a synonym for rowversion. This means that it's automatically generated and guaranteed to be unique for each record in a table. Its primary purpose is for concurrency control and to track row changes.
Datetime: Stores Actual Date and Time
Datetime, on the other hand, is a true date and time data type. It allows users to store the specific date and time, including seconds and microseconds. It can be client-specified during insert or update operations, meaning the value is provided by the application using the database.
Key Differences Summary:
Feature | Timestamp | Datetime |
---|---|---|
Primary Purpose | Concurrency control and uniqueness | Storing specific date and time |
Generation | Automatically generated as rowversion | Can be specified by the client |
Uniqueness | Guaranteed to be unique | Not guaranteed to be unique |
Data Type | Synonym for rowversion | True date and time data type |
Therefore, while both timestamp and datetime can be used to store date time information, their primary function and implementation differ significantly. Timestamps provide unique identifiers for record versions, while datetimes offer flexibility in storing and managing precise date and time values.
The above is the detailed content of What\'s the Difference Between Timestamp and Datetime in SQL Server?. For more information, please follow other related articles on the PHP Chinese website!