About database and database management

What’s a database and database management? What is the career scope of a database professional?

A simple database consists of one or more table/s with each table consisting of rows and columns that define the data columns or at sometimes also referred as database attributes. For a telephone book, the table columns define data columns such as name, phone number and it may have nonmandatory attributes as address, city, and state, while a table row, or record, contains data for each contact entry in the phone book.

A database management system helps to manage data successfully and allow users to perform multiple responsibilities with ease. A database software management system, stores, organizes and manages a sizable amount details within a single software application. Make use of this system increases the efficiency of the business and reduces overall costs.

With no database management system, tasks have to be done manually and will take more time. Information can be categorized and structured to suit the needs of the company or organization. Organisations have secured database management system, where every user of the system gets verified for authenticity and as per defined authorization rules is given access to the database management system.

For example, a company’s account department uses the database to manage financial records, distribute legal and processed information to employees and create updated financial reports, creating a smoother and more organized working environment.

Lets us discuss the following listed aspects of Database Management system
• Historical Evolution from flat file to database management systems.
• Purpose and goals of a database management system.
• Three models of database management systems, viz., Hierarchical, Network, and Relational
• The relational data model including normalization, SQL with suitable examples.

A Relational database has multiple tables and defined the relationship between the data attributes. Records and data attributes from each table are queried to extract meaningful data.

Bonus Information: Major components in a database environment are data it self, the hardware, the software, the people, and the techniques to manage data. Data records are facts collected from various data sources. The hardware is the physical devices in the environment of the database systems. In most of the cases Hardware Systems and network, database management systems, and business applications make up the entire software and hardware business system environment. Men and women working in this environment can be titled as (but not limited to) System administrator, Database administrator, programmers and system architects, end users, etc..

If you look to build your career just around the database environment you can look for job titles as Database Administrator, Database Architect, Database Programmer; the career growth depends on your competency about the subject.

Evolution of database and database management system with time.

Historical Evolution from flat file to database management systems. Purpose and goals of a database management system. Three models of database management systems, viz., Hierarchical, Network, and Relational. Following list is about how database management system/s have evolved with time.

• 1965 – 1980 Hierarchical / Network Models: VAX DBMS
• 1980 – 1990 Relational Model: IBM DB2, Oracle, Sybase, Informix
• 1990s Object-Oriented DBMS: ObjectStore, Versant
• The late 90s:
  • Object-Relational Databases >> Informix Universal Server, Oracle Universal Server
  • Data Warehousing >> Teradata + many

Wonder why such evolution took place? Let me list down some reasons for the same. Most of the reasons are related to how business changed over the years. Increasing demand for meaningful data by the business to support customers and take strategic business decisions.

• Complex objects and relationships
• Multiple data types
  • Numbers, text, images, audio, and video
• Multiple dimensions of Information
  • Structural, low-level, high-level (metadata)
• Real-time demand and response to high volume data for the business processes.
• User expectations on the rise
  • Better interfaces / visualizations
  • Going beyond raw data to meaningful information
    • Knowledge discovery and data mining
      • Data Extraction, cleaning, mining, etc..

Future of database and Database management Systems will further see changes as we see a lot of technology advancement.

What is Database Model? And explain a well-known model.

A simplified abstraction of real-world event or condition is termed as a model. The database model is a collection of logical constructs used to describe the structure of a database. Structure of a database includes the data types, relationships, and constraints that should hold on the data. A data model is useful for a number of reasons.

• It helps to understand the relationships among different components in a system design.
• It shows the user more clearly how a system will function; Users are very concerned about data and information, they want to know if there will be adequate data available to perform their job.

Database models are classified into two types Conceptual Data Models (Focuses on What) and Implementation Data Models (Focuses on How)

The most common type of data model is the Entity-Relationship Model, also at times referred as ER-Model. Some of the industry other know database models are Hierarchical Model, Network Model, Relational Model, Object Oriented Model.

ER Model

This model is for a user to follow and serves as an excellent communication vehicle, the diagrammatic representation of an ER Model is an ER Diagram. ER Diagram consists of Objects (Entities) and relationships.

Example, look at the diagram above. A customer purchases a product. The two entities here are “Customer” and “Product”; The relationship is “Purchases”. In the above ER Diagram entities are represented by rectangles and a relationship by a diamond.
Alternatively, the above diagram can also be as follows.

Entities also have attributes, which are the fields we should include in a file record. A product has a product number, size, description, price, cost, and so on.

Advantages and Disadvantage of ER Model.

Advantage: Exceptional conceptual simplicity, Visual representation, Effective communication tool Disadvantage: Limited constraint representation, Limited relationship representation.