Should You Use '*' When Creating Database Views?

Using '*'' to Construct Views: Potential Pitfalls and Considerations

In database design, it is often recommended to avoid using '*' to build views. This practice can lead to several problems.

One primary issue arises when dealing with tables that have fields with duplicate names. In the example provided, if both table1 and table2 have a field named "field1", selecting all fields with * will result in ambiguity, as the view will not specify which "field1" to retrieve. This can lead to unexpected results or even errors.

Another potential problem arises when the underlying tables change. If additional columns are added to either table1 or table2, the view will continue to be valid, even though the data it returns may no longer be meaningful. This can break applications that rely on the view, as they may fail to anticipate the changes in the underlying tables.

Conversely, some database vendors may allow views to automatically adapt to changes in the underlying tables, ensuring that the data they return remains consistent. However, this behavior is not guaranteed and should not be relied upon.

In conclusion, while using '*' to build views can be convenient, it should be avoided due to the potential for ambiguity, unexpected results, and lack of flexibility. Explicitly specifying the fields to be included in a view provides more control, clarity, and safeguards against potential issues.

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