CS409 Handouts Complete

CS409- Introduction to Database Administration

Lesson 1: Defining data, information & database

What is Data and Information?

Data are the raw bits and pieces of information with no context.

Anything which is not necessarily meaningful to human being.

Raw facts/Un-processed information.

Data are the raw bits and pieces of information with no context. If I told you, “45, 32, 41, 75,” you would not have learned anything.

The numbers 10, 22, and 119 are data someone can think these are lengths and other may think room numbers. Similarly, 1.5, 2.5, 31.5, MAY represent lengths of some iron rods.

Data can be quantitative or qualitative. Quantitative data is numeric, the result of a measurement, count, or some other mathematical calculation. Qualitative data is descriptive. “Dark Brown” the color of hair, is an example of qualitative data. A number can be qualitative too: if I tell you my favorite number is 5, that is qualitative data because it is descriptive, not the result of a measurement or mathematical calculation.

Information

Data Processed to reveal its meaning Information is meaningful In today’s world, accurate, relevant, and timely information is the key to good decision making good decision making is key to survival in today’s competitive and global environment By itself, data is not that useful. To be useful, it needs to be given context.

Returning to the example above, if I told you that “45, 32, 41, 75” are the numbers of students that had registered for upcoming classes, that would be information. By adding the context – that the numbers represent the count of students registering for specific classes – I have converted data into information.

Once we have put our data into context, aggregated and analyzed it, we can use it to make decisions for our organization. We can say that this consumption of information produces knowledge. This knowledge can be used to make decisions, set policies, and even spark innovation.

The final step up the information ladder is the step from knowledge to wisdom. We can say that someone has wisdom when they can combine their knowledge and experience to produce a deeper understanding of a topic. It often takes many years to develop wisdom on a particular topic and requires patience.

What is database?

A database is a collection of related data. By data, we mean known facts that can be recorded and that have implicit meaning. For example, consider the names, telephone numbers, and addresses of the people you know. You may have recorded this data in an indexed address book or you may have stored it on a hard drive, using a personal computer and software such as Microsoft Access or Excel. This collection of related data with an implicit meaning is a database.

Lesson 2: Introduction to DBMS & its environment for DBA

What is DBMS and its examples?

Database Management System (DBMS) is a software for storing and retrieving users’ data while considering appropriate security measures. It consists of a group of programs which manipulate the database. The DBMS accepts the request for data from an application and instructs the operating system to provide the specific data. In large systems, a DBMS helps users and other third-party software to store and retrieve data.

DBMS allows users to create their own databases as per their requirement. The term “DBMS” includes the user of the database and other application programs. It provides an interface between the data and the software application.

Example of DBMS

Oracle IBM DB2 Ingress Teradata MS SQL Server MS Access MySQL

2- Tier Database Architecture

In two-tier, the application logic is either buried inside the User Interface on the client or within the database on the server (or both). With two-tier client/server architectures, the user system interface is usually located in the user’s desktop environment and the database management services are usually in a server that is a more powerful machine that services many clients.

3- Tier Database Architecture

In three-tier, the application logic or process lives in the middle-tier, it is separated from the data and the user interface. Three-tier systems are more scalable, robust and flexible. In addition, they can integrate data from multiple sources. In the three-tier architecture, a middle tier was added between the user system interface client environment and the database management server environment. There are a variety of ways of implementing this middle tier, such as transaction processing monitors, message servers, or application servers.

Forms

Forms are used for entering, modifying, and viewing records. You likely have had to fill out forms on many occasions, like when visiting a doctor's office, applying for a job, or registering for school. The reason forms are used so often is that they're an easy way to guide people toward entering data correctly. When you enter information into a form in Access, the data goes exactly where the database designer wants it to go in one or more related tables.

Forms make entering data easier. Working with extensive tables can be confusing, and when you have connected tables, you might need to work with more than one at a time to enter a set of data. However, with forms it's possible to enter data into multiple tables at once, all in one place. Database designers can even set restrictions on individual form components to ensure all of the needed data is entered in the correct format. All in all, forms help keep data consistent and organized, which is essential for an accurate and powerful database.

Reports

Reports offer you the ability to present your data in print. If you've ever received a computer printout of a class schedule or a printed invoice of a purchase, you've seen a database report. Reports are useful because they allow you to present components of your database in an easy-to-read format. You can even customize a report's appearance to make it visually appealing. Access offers you the ability to create a report from any table or query.

Queries

Queries are a way of searching for and compiling data from one or more tables. Running a query is like asking a detailed question of your database. When you build a query in Access, you are defining specific search conditions to find exactly the data you want.

Queries are far more powerful than the simple searches you might carry out within a table. While a search would be able to help you find the name of one customer at your business, you could run a query to find the name and phone number of every customer who's made a purchase within the past week. A well-designed query can give information you might not be able to find just by looking through the data in your tables.

DBMS Languages

A Software Package that enables users to define, create, maintain, and control access to the database. Data Definition Language (DDL) Data Manipulation Language (DML) Control access (DCL):