Conceptual Questions
1.What is a relational database management system (RDBMS)?
RDBMS is a DBMS designed specifically for relational databases.
2.What is SQL?
QL is a domain-specific idiom used in programming and designed for maintaining data held in a relational database management system.
3.What is an ER model?
An entity-relationship model details a interrelated things of interest in a specific domain of knowledge. A primary  ER model is composed of entity types and specifies relationships that can exist among entities.
4.Define the following terms: One-to-one relationship, one-to-many relationship, and many-to-many relationship.
Is a type of cardinality that comes to the relationship between two entities 1 and 2 in which one element of A may only be linking from one element of 2.
5.What is the purpose of a primary key? Why should it be unique?
To implement a relationship among 2 tables in a relational database. Unique key constraints are used to ensure that data is not cloned in 2 rows in the database.