Summary of Relational Database
1. Relational databases underlie most modern integrated AISs.
a. They are the most popular type of database used for transaction processing.
b. In this chapter, we’ll define the concept of a database.
2. Database systems were developed to address the problems associated with the proliferation of master files.
a. For years, each time a new information need arose, companies created new files and programs.
b. The result: a significant increase in the number of master files.
3. A database is a set of inter-related, centrally coordinated files.
4. A database management system (DBMS) serves as the interface between the database and the various application programs.
5. Database technology provides the following benefits to organizations:
a. Data integration
b. Data sharing
c. Reporting flexibility
d. Minimal data redundancy and inconsistencies
e. Data independence
f. Central management of data
g. Cross-functional analysis
6. The DBMS handles the link between the physical and logical views of the data.
a. Allows the user to access, query, and update data without reference to how or where it is physically stored.
b. The user only needs to define the logical data requirements.
7. Schemas
a. A schema describes the logical structure of a database.
b. There are three levels of schema.
i. Conceptual level ii. External level iii. Internal level
8. Changing a database
a. The set of commands used to change the database is known as data manipulation language (DML). DML is used for maintaining the data including:
i. Updating data ii. Inserting data iii. Deleting portions of the database
9. A DBMS is characterized by the type of logical data model on which it is based.
a. A data model is an abstract representation of the contents of a database.
b. Most new DBMSs are called relational databases because they use the relational model developed by E.F. Codd in 1970.
10. The relational data