Business Rules and Data Models Essay

designed for flexibility, and would typically include many more attributes, even if some of them are blank for many of

* Per the text, when databases are developed, they are modeled around business rules, so they accurately support a business function or operation.

What is the probability that a randomly selected order will require more than six days?

Hierarchical database have data in a tree like structure with a parent to child relationship (one-to-many). The parent could have many children but the children have only one parent. All the attributes of the data is in a list under one entity type.

Same Domain Values: Data within a column adheres to a single domain. For instance a geneder column will have values for gender but no other.

Identity - Characteristics and interests that somebody recognises as belonging uniquely to them and makes up their individual personality for life.

(TCO 7) What is the name for a unique key that is constructed from multiple columns?

An attribute is an arrangement that defines the property of an object, folder, or file. Attributes should more correctly be considered metadata because it is the settings of the specified object, folder or file.

The purpose of a primary key, and the appropriate selection and assignment of a field as primary key.

Write an unambiguous definition for each attribute. Then, redraw PE Figure 7-1 by placing the six (and additional) entities in this case on the diagram along with their associated attributes.

Database, it is a place use to store lots of data. It can be seen as a filing cabinet. And database management system (DBMS) is software that specificity designs for managing the data in database such as create, update or delete them. General is including security, retrieval and backup features. User also allows using the data to create a report or share data with multi-user.

Entities: Entities are objects that are located in a data base. Entities allow you to store data objects in the systems data base. These are set out in a table form in the data base. Primary keys, foreign keys, referential integrity and data redundancy are all part of entities.

there are attributes that apply to some but not all instances of an entity type.

| (TCO A) Projects have specific attributes. Which of the following is not an attribute?

(1) Every time attribute A appears, it is matched with the same value of attribute B, but not the same value of attribute C. Therefore, it is true that: