Chap 9 Review questions
1. Explain the main differences between a file processing system and a database system.
A database coordinates the physical and logical access to the data; a file-processing system only coordinates physical access to the data.
A DBMS reduces the amount of data duplication.
A DBMS is designed to coordinate and permit multiple users to access data at the same time. A file processing system is much more restrictive in simultaneous data access.
2. What is a DBMS? Briefly describe the components of a DBMS.
A database consists of linked tables that form an overall data structure. A database
management system (DBMS) is a collection of tools, features, and ...view middle of the document...
Common fields can be used to link entities in various types of relationships.
4. What are entity-relationship diagrams and how are they used? What symbol is used to represent an entity in an ERD? What symbol is used for a relationship? What is cardinality, and what symbols do you use in the crow’s foot notation method?
An entity-relationship diagram (ERD) is a graphic representation of all system entities and the relationships among them. The ERD is based on entities and data stores in DFDs prepared during the systems analysis phase. The relationship between two entities also is referred to as cardinality. A common form of cardinality notation is called crow’s foot notation, which uses various symbols to describe the characteristics of the relationship. The three basic relationships represented in an ERD are one-to-one (1:1), one-to-many (1: M), and many-to-many (M: N).In a M: N relationship, the two entities are linked by an associative entity.
5. What are data warehousing and data mining? Are the terms related?
A data warehouse is an integrated collection of data that can include seemingly unrelated information, no matter where it is stored in the company. Because it can link various information systems and databases, a data warehouse provides an enterprise-wide view to support management analysis and decision making.
Data mining software looks for meaningful data patterns and relationships.
For example, data mining software could help a consumer products firm identify potential customers based on their prior purchases.
Personally I don’t think that those terms are related.
6. What is the criterion for a table design to be in first normal form? How do you convert an unnormalized design to 1NF?
A table is in first normal form...