Database Notes

Topics: Relational model, Database, Relational database Pages: 8 (1252 words) Published: October 13, 2012
ACSG 552 – 01.
Processor Florence Appel
Advanced Database Class- Spring 2009.
Assignment #01.
Friday, January 23, 2009
Due in class on Thursday, Jan. 22.

o Chapter 2
▪ Review Questions, pp. 54-55: 2, 5, 6, 9, 18, 19 ▪ Problems, pp. 55-59: 1, 2; 12-15; 19-21; 22; 25abcde Chapter 02:
Review Questions: pp. 54-55.

#02) What is a business rule, and what is its purpose in data modeling?

The business rule is a brief, precise and ambiguous description of a policy, procedure, or principle within a specific organization business rules apply to every organization, and uses data and generates more data. Data modeling:

Relatively simple representation, usually graphical, of more complex real world date structures. Data Modeling is in effect a blueprint contaminating all the instructions to build a database that will melt all end, user requirements. Data modeling clarifies such communication by reducing the complexities database design, to more easily understand abstraction that define entities and the relations among them.

#05) What three languages were adopted by the DBTG to standardize the basic network data model, and why was such standardization important for users and designers?

-Data management language (DML).
-Data deviation language (DDL).
-SQL, data manipulation language to work the data in the data in the database. -To help establish database standards.
-Make standards specifications.
-Distinct components for databases.

#06) Describe the basic of the features of the relational data model and discuss their importance to the end user and designer?

• Automatic transformation, to create a database revolution. • Database relations work on by describing precise, set of data manipulation constructs, based on new advanced concepts. • Relational model has all the basic functions from previous versions of database, plus more functionalities now. • In addition more other functions are now available, in the new relational model to implement. • Such as:

• Ability to hide complexities.
• Manage physical details.
• Use collection of tables related to each other, and link them effectively. • The end user can manipulate and query the data in a way that seems, intuitive, and logical. • Importance to the end, user and designer.

#09) Why is an object said to have greater semantic content then an entity?

OODM is said to be a semantic data model because semantic indicates OODM reflects a very different way to define and use entities, an object is described and represented by its factual content. Unlike entity, an object includes information about relationships between the facts within the object. Includes information about its relationship and objects, objects give greater meaning.

#18) What is the logical independence?

Change to the internal model without altering anything in the conceptual model, you then have logical independence.

#19) What is physical independence?

Change the physical model without affecting the internal model then you have physical independence.

Chapter 02:
Problems, pp. 55-59: 1, 2; 12-15; 19-21; 22; 25abcde.

#1) Write the business rule(s) that govern the relationship between AGENT and CUSTOMER.

Match customer to Sales Agent. Through Customer data stored in table and Sales representative stored in another in customer table. Agent code matches agent code, in agent table. Tables are independent of one another, and then can related to be relational.

#2) Given the business rule(s) you wrote in Problems 1, create the basic Crow’s Foot ERD?


#12) Using the Hierarchical representation representation show in frame P@.12, answer a, b, and c:

a. Identity the segment types:
Painter & painting segments.

b. Identify the component’s that one equivalent to the file system fields: Painter number....
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