ErVis' Blog

In week 8 we used to study about what is a database and what is a DBMS?

According to my research and my information I list down the basic details about Database and DBMS.

As we know databases are designed to offer an organized mechanism for storing, managing and retrieving information. They do so through the use of the tables. If you’re familiar with spreadsheets like Microsoft Excel, you’re probably already accustomed to storing data in tabular form. It’s not much of a stretch to make the leap from spreadsheets to databases. Let’s take a look.

Database Tables

Just like Excel tables, database tables consist of columns and rows. Each column contains a different type of the thing that is attributing and each row corresponds to a single of record. For example, imagine that we were building a database table that contained names and telephone numbers. We’d probably set up columns named “FirstName”, “LastName” and “TelephoneNumber.” Then we’d simply start adding rows underneath those columns that contained the data we’re planning to store. 

If we were building a table of contact information for our business that has 50 employees, we’d wind up with a table that contains 50 rows.

Databases and Spreadsheets

At this point, you’re probably asking yourself an obvious question – if a database is so much like a spreadsheet, why can’t I just use a spreadsheet? Databases are actually much more powerful than spreadsheets in the way you’re able to manipulate data. Here are just a few of the actions that you can perform on a database that would be difficult if not impossible to perform on a spreadsheet:

·         Retrieve all records that match certain criteria

·         Update records in bulk

·         Cross-reference records in different tables

·         Perform complex aggregate calculations

You can correlate information from multiple tables in a database by creating foreign key relationships between the tables.

A DBMS has many uses:

- it enables users to access and manipulate the database.
- it provides a building block in constructing data processing systems for applications requiring database access – MIS or systems for accounting, production and inventory control or customer support.
- it helps the DBA perform certain managerial duties.

The name ‘database management system’ was chosen recognizing that different names are in use and different types of systems exist. Substantial generalization is assumed in any DBMS of interest without using ‘generalized.’ ‘Data is preferred over ‘information’ for the various reasons cited.

Functions of a Database Management System:
- Database Definition
- Database creation (storing data in a defined database)
- Retrieval (query and reporting)
- Update(Changing the contents of the database)
- Programming User Facilities for system development)
- Database revision and restructuring
- Database integrity control
- Performance Monitoring

Overview of Relationships in Database Management:

In a database environment, the main components, or players are database users, a database administrator, applications programs, and the DBMS. People can access the database directly using a DBMS, or they can write a program (or have a programmer write one for them, or use a previously written program) in cases requiring special or more complex processing. The DBA establishes and periodically revises the database to meet the needs of the users. The DBA establishes integrity controls.

The users and the DBA communicate formally and informally about system use and database access, and about the regulations and standards in force. Application programs and the DBMS are processes executed by machine. While accessing and controlling the database, the DBMS has three distinct interfaces – with users, with the DBA and with programs. Database users access the database directly using the facilities of the database management system or through a program written by themselves. The database administrator establishes the database and the controls on people and programs using the database.

The Database Administrator must be a manager, rather than a technician – seeking to meet the needs of people who use data. Since many users may share the same data resources, the DBA must be repared to mediate conflicting needs and objectives, sometimes imposing a compromise solution. Functions of Database Administration are as follows:

- Define, acquire and retire data according to the user needs.
- Provide tools to access and update the data and produce reports.
- Inform and assist users in planning and using data resources and database management tools.
- Maintain database integrity by protecting its existence, maintaining its quality and controlling access to private data.
- Monitor operations for efficient performance and integrity threats.

The central idea behind managing data resources is getting a handle on organizational data resources which support operations and management decisions. Proper management of data also promotes the use of data. Solving the problem of data management entails both the administrative and technical factors: creating an effective organizational structure and appointing a responsible authority called the Database Administrator and using computer based facilities along with associated operating personnel and procedures.