Databases And Data Warehouses

Databases and Data Warehouses

1. How are data represented?

Data are raw materials used to produce information.

It is any facts, text, and other multimedia objects that we are interested in capturing and storing.

Information is data that have been processed in such a way that it can increase the knowledge of the person who uses it.

Data Representation

a) Field Ð'- The smallest unit of data that has meaning to humans.

b) Record Ð'- Collection of fields that contain information concerning specific thing or event.

c) File - A collection of records.

d) Database Ð'- A group of related files

2. What is business intelligence and its role?

Business intelligence is knowledge about your customers, your competitors, your partners, your competitive environment, and your internal operations that gives you the ability to make effective, important, and strategic business decisions.

IT tools help process information to create business intelligence according to:

a) OLTP Ð'- gathering of input information, processing that information and updating existing information to reflect the gathered and processed information. Databases and DBMS support OLTP. (Operational database)

b) OLAP Ð'- manipulation of information to support decision making. Data warehouses and data mining tools support OLAP.

3. How are transactions recorded and processed.

Transaction Ð'- A record of an event.

Processing Ð'- Procedures to store, retrieve, and manipulate records of events.

Traditional file processing system:

1. Two files

Ð'* Master file Ð'- relatively static data is stored

Ð'* Transaction file Ð'- information relevant to the most recent transaction is stored.

2. Batch processing

Ð'* Data grouped together and processed at some point after original transactions occurred.

Ð'* Data written on paper/off-line, and captured electronically later ; records assessed in sequential order.

OLTP:

1. Data captured directly/online and processed immediately.

2. Real-time processing: a form of computing in which the transactions are processed as they occur and data updates immediately.

4. List and describe key characteristics of relational database

Relational database model uses a series of logically related two-dimensional tables or files to store information in the form of a database.

Key characteristics:

a) Collection of information Ð'- Composed of many files or tables of information that are related to each other.

b) Contain logical structures Ð'- You care only about the logical information and not about how it's physically stored or where it's physically located.

c) Have logical ties among the information Ð'- All the files in a database are related in that some primary keys of certain files appear as foreign keys in others.

d) Possess built-in integrity constraints Ð'- When creating data dictionary for a database, you can specify rules by which the information must be entered.

5. Role of database management system (DBMS) in creating and using databases.

DBMS helps you specify the logical organization for databases and access and use the information within a database.It is software that controls the capture, storage and access to data in a database.

6. Define the 5 software components of a DBMS.

DBMS engine

Ð'* Accepts logical requests from the various other DBMS subsystems, converts them into their physical equivalent, and actually accesses the database and data dictionary as they exist on a storage device.

Ð'* Separate