What are the advantages and disadvantages of using a synthetic key in a database?

A synthetic key is an artificial unique identifier for a record in a database, usually an integer auto-increment ID that does not carry business meaning.

Advantages:

• Ensures uniqueness and simplifies indexing.
• Facilitates relationships between tables (e.g., foreign keys).
• Independent of changes in business logic or data.

Disadvantages:

• Does not reflect real data, which can complicate debugging.
• Requires an additional field in the table.
• Sometimes can lead to redundancy if a natural key already exists and is unique.

Ultimately, synthetic keys are convenient for technical implementation and scalability, but it is important to evaluate the necessity of their use in the context of a specific task.