Class Exercise:  Relational Model Concepts

When answering the questions below refer to these relation definitions for a simple
    database schema:
    DEPARTMENT(deptno, dname, location, budget); 
    EMPLOYEE(empno, ename, job, manager, hiredate, salary, deptno);

1.  Identify the major components of the relational model.



2.  In a relational database, what is represented by the database structure 
    called a table (or relation)?

          

3.  What is represented by a column in a table. Describe the characteristics of 
    a table column.  



4.  What is represented by a table row?



5.  What is meant by the term domain of values? Domains may be defined in 
    physical and logical terms; distinguish between the two definitions.



6.  Identify and describe the different types of keys associated with these
    tables?
      


7.  Nominate candidate keys for these relations. Choose and define primary keys.
    What are the alternate keys? Show how to place not null and unique 
    constraints on the alternate keys.





8.  How are relationships represented and the relations linked in a relational 
    database? 



9.  Name, describe, and give examples for three kinds of database relationships.





10.  What is a foreign key? Define foreign keys for this database.





11. What is a database schema?