you need to turn your attention to the business requirements. A typical business requirement might be that all employees are at least 16 years of age. Regardless of the selected RDBMS, business requirements are ultimately enforced by implementing database constraints on tables and columns. These constraints include:

• A NOT NULL constraint 
• A unique constraint 
• A primary key constraint 
• A foreign key constraint 
• A check constraint 

Database designers implement some and/or all of the above database constraints to meet the business requirements established during the analysis phase of the Database Life Cycle.

In your initial post, provide two examples of new business requirements and the database constraints that could be implemented to enforce them. Describe in detail the role of the constraints and provide the SQL statements required to create them in the database. Explain the advantages and disadvantages of implementing database constraints as well as any potential performance issues your database constraints may cause.