Essay on Info Systems

Submitted By FDAfoodbanker
Words: 519
Pages: 3

1. Write the definitions for the following terms
a. Table- 2 by 2 Matrix where you store all your data.
b. Record- is a row of data in a table, one sales event.
c. Row- one instant in a table is a prim.
d. Primary key- some data elements that is customized in a row. Like SSN.
e. Foreign key- a data element in a related table that is from a “foreign” table.
f. Compound primary key- are two or more primary keys are combined together makes a ‘compound’ key.
g. Query- is a function that seeks out questions posted in the database.
h. Entity- is an event or characteristic of something that a database will contain.
I. Attribute- are “characteristics” of an entity that contain more or more “relationships”.Ex. ( John Doe (Entity), Home and phone number, Home address (Attributes).
2. What are the categories or types of entities you would normally identify in your database design? Types of entities in a basic database are Employees, Customers, Inventories, Suppliers. Most databases are having organized tables that will individualize each entity with specific data.
3. What is a one-to-many relationship? The first entity is related to just one instance of the second entity. The first entity is related to many instances of the second entity, but each instance of the second entity is related to only one instance of the first.
4. What do you do in your database design if there is a many-to-many relationship between two entities?
Most D.M.S. only support one-to-many relationships so it’s necessary to implement relationship through cross-reference tables. Many to many relationships are cardinal references to the relationship between two entities. For example by adding two foreign keys with similar characteristics the primary key will become the many-to-many-relationship.
5. What are the 6 database design rules in your own words?
` 1) You will not need to table to categorize the business. A single database can represent the entire business. 2) Show the differences between entities in the business description. Distinguish between things and Events like products and revenue. 3) Describe…