What disadvantage is associated with lossless join and dependency preserving decomposition?

The main disadvantage associated with lossless join and dependency preserving decomposition in database normalization is the potential increase in complexity and redundancy.

1. Increased Complexity: The process of decomposing a relation into multiple relations can make the database schema more complex. It can also make queries more complex, as they may need to access multiple relations instead of a single one.

2. Potential Redundancy: While the goal of normalization is to reduce redundancy, improper or excessive decomposition can actually introduce redundancy. This can occur if the decomposed relations share common attributes.

3. Performance Issues: Decomposition can lead to performance issues. This is because joining multiple relations is often more computationally expensive than accessing a single relation.

4. Update Anomalies: If the decomposition is not dependency preserving, it can lead to update anomalies. This means that changes to the data in one relation may require changes to data in other relations to maintain consistency.

5. Loss of Information: If the decomposition is not lossless, it can lead to loss of information. This means that it may not be possible to reconstruct the original relation from the decomposed relations.