1- Based on your understanding of specialization and generalization constraints,

1- Based on your understanding of specialization and generalization constraints, use your own words to define and discuss the two primary constraints: Disjointness Constraint and Completeness Constraint.2- Show the schema mapping of the following Payment EER schema diagram, using Option 8A: Multiple relations-Superclass and subclasses. 3-SQL constraints are used to specify
rules for the data in a table. From what has been studied, what is the benefit
of using constraints in DB. Also, explain three common SQL constraints.4- sing the relational algebra operations, write the following queries on the COMPANY relational database schema shown in the figure below.
Retrieve the address of employees in department 2 who work less than 5 hours per week on the ‘ProductX’ project.
Retrieve the names and salary of employees who work on every project.