What is meant by database management?

Database management allows people to store, retrieve, and organize data from a computer. Database management defines the data operations, storage, and security practices of the database administrators throughout the data life cycle. Database management involves supporting, designing, and implementing the stored data to maximize its value.

What is database management software?

The database management software allows the user to design a personalized database to meet the user's analytics and reporting needs. It is mostly used to store, manipulate, and manage the data in the database environment. The database design supports creating, maintaining, and implementing the organization-wide DBMS. Using Structured Query Language(SQL) queries, the DBMS package allows the user to perform operations like creating, storing, and updating data. Some popular DBMS softwares are Oracle RDBMS, Informix, SQLite, etc.

What is database management system?

The full form of DBMS is a Database Management System. It is a software system that uses the standard method of retrieving, cataloging, and running queries on the data. DBMS manages data and allows the users to control the data by creating, updating, deleting, and reading. Database management system delivers security and also ensures data integrity.

Example: Oracle, Microsoft Access, MySQL, Microsoft Access, PostgreSQL, SQL server, and FoxPro

Different tasks of Database management system

DBMS allows the user to execute the following task,

• Data definition is used for modification, removal, and creation of definition that defines the organization of data in the database.
• Data updation is used in inserting, modifying, and deleting the original data in the database.
• Data retrieval is used in retrieving some data from the database and the retrieved data is used by the application for certain purposes.
• User administration is used to register and monitor the user, manage data integrity, enforce data security, monitor the performance, and recover the information (which is manipulated by unexpected failure).

Database models

What is meant by database model?

The logical design and structure of the database are defined by the database model. The other name for the database model is data schema. It defines how to store, update, and access the data in the database management system.

Types of database models

The various types of database models are,

Hierarchical model

The first DBMS model is the hierarchical model. It is a database model which assembles the data in a tree-like structure with one root node and expands the tree by adding the child node. This database model has a one-to-many relationship among the data. The hierarchy will start from the root node and expand the tree by inserting the child node into the parent node.

Advantages

• Fast in data traversal.
• Maintains data integrity.

Disadvantages

• Does not support complex relationships.
• If the parent node is deleted then the child node gets deleted automatically.

Network model

A network model is an extension of the hierarchical model. The network model was the most popular one before the relational model. The difference between the hierarchical and network model is, the record can have more than one parent (many-to-many relationships). The network model replaces the hierarchical tree with a graph.

Advantages

• Faster access of data.
• When there is a change in the parent node then it will affect the child node.

Disadvantages

• Quite complex to create changes (such as deletion, insertion, and updation).
• The system becomes complex when it handles multiple relationships.

Relational model

The most widely used model is the relational model. The data can be maintained in a two-dimensional table. The data is stored using columns and rows. The basic structure of a relational model is a table, where the table is known as a relation. The relational model is stored in fixed structures and controlled using Structured Query Language(SQL).

Advantages

• Compared to the hierarchical model, this is quite simple.
• Structural independence can be achieved using the relational model.

Disadvantages

• Requires a powerful hardware computer.
• The poor database development can slow down the database (when it extends).

Entity-relationship model

The short form of ER model is an entity-relationship model. It is a high-level data model diagram. The problems can be described in pictorial form and make it simple to understand for both the stakeholders and developers. The three components of ER model are,

• Entity: Entity can represent a concept, place, or person. Example: The entities of a school management system are department, students, teachers, course, etc
• Attributes: The real-world property of an entity is called attributes. Example: The property of the entity teacher is id, name, salary, gender, age, etc.
• Relationship: Relationship defines how the attributes are related. Example: Teacher and department (teacher working for the department).

Advantages

• Widely used model by the database designer to communicate their ideas.
• Easy to convert to any kind of database model.

Disadvantages

• Some data can be hidden or lost.
• No industry standards in developing the ER models (notation usage will differ from one developer to other).

Characteristics of DBMS

• A digital repository is used to manage and store the data.
• Provides a logical and clear view of the process which manipulates the data.
• The complex relationship can be reduced using a database management system.
• The database management system provides data security.
• The DBMS can be viewed from different viewpoints based on the user requirement.

Pros of DBMS

• Backup: DBMS provides backup and recovery subsystem which create automatic data backup from the software and hardware failure and restores the information if required.            
• Maintenance: The maintenance of DBMS is quite easy due to the centralized nature of the database system.
• Data sharing: In DBMS, only authorized users of the organization can exchange the information among the users.
• Data redundancy: DBMS can simply control the data redundancy, because it stores all kinds of data in one database file and that recorded data is placed in the database.
• Reduced time: DBMS reduces both the development and maintenance time.
• User interface: DBMS provides various user interfaces like application program interface, graphical user interface, etc.

Cons of DBMS

• Software and hardware cost: DBMS requires a larger memory size and data processor with maximum speed to run DBMS software.
• Complexity: Additional requirements and complexities are created using the database system.
• Impact of failure: Failure highly impacts the database, because the organization stores the data in single database. If the database is damaged due to database corruption or electic failure then the data might be lost forever.
• Size: DBMS occupies large space on the disk and also huge amount of memory to run effectively.

Context and Applications

This topic is important for postgraduate and undergraduate courses, particularly for,

• Bachelors in Computer Science.  
• Bachelors in Computer Application. 
• Masters in Computer Application. 

Practice Problems

Question 1: The most widely used database model is ____.

1. Hierarchical model
2. Relational model
3. ER model
4. Network model

Answer: Option b is correct.

Explanation: Relational model is the most used database model where the data is organized in the two-dimensional table. The relationship in the table can be maintained by storing a common field.

Question 2: Select the function of DBMS.

1. Storing data
2. Providing multi-users access control
3. Data Integrity
4. All of the above

Answer: Option d is correct.

Explanation: The purpose of creating DBMS is to store the data. The data stored in the database management system can be can accessed by multiple users (if the access is provided). The data stored will be accurate and complete hence providing data integrity.

Question 3: Select the popular database management software.

1. IBM DB2
2. Oracle RDBMS
3. OrientDB
4. All the above

Answer: Option d is correct.

Explanation: The given three options (IBM DB2, Oracle RDBMS, and OrientDB) are the popular database management software. Among the three the most used is Oracle.

Question 4: What is DBMS?

1. Collection of queries
2. High-level language
3. Programming language
4. System to store, modify and retrieve data

Answer: Option d is correct.

Explanation: DBMS is a storehouse where the authorized user can create a database to store, modify, or retrieve the organized data in the table. It can be modified or retrieved by users who have access to DBMS. The database management defines the data operations, storage, and security practices of the database administrators throughout the data life cycle.

Question 5: Select the three components of ER model.

1. Entity, attribute, and relationship
2. Insert, update, and delete
3. Define, retrieve, and update
4. None of the above

Answer: Option a is correct.

Explanation: The three components of ER model are, Entity can represent person, place, or a concept. Attributes are the real-world property of an entity and relationship defines how the attributes are related.