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Database Management Systems6 min read

Database Models

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DBMS Database model defines the logical design of data in a Database Management System. A model also describes the relationships between different types of data. In this tutorial we will study about E-R Model, Network Model, Relational Model and Hierarchical Model.

DBMS Database Models

In this article, we will learn about various types of databases. We will discuss its characteristics, advantages, disadvantages also.

Types of Databases in DBMS

There are various types of databases to store a variety of data. We will discuss 10 types of databases.

  • Centralized databases
  • Distributed Databases
  • Relational Databases
  • NoSQL Databases
  • Cloud Databases
  • Object-oriented Databases
  • Hierarchical Databases
  • Network Databases
  • Personal databases
  • Operational Databases

We will discuss each of them in detail later in this lesson.

1. Centralized Databases

It stores data in a centralized database system. The centralized database contains application procedures that help the users to access the data even from a remote location. There is no duplication of data and very little organization is required. It is less costly as compared to others and provides data consistency. It provides better data quality, which enables organizations to establish data standards but highly dependent on network connectivity. Due to its large size, it increases the response time for fetching the data. Also, entire data could vanish due to small server failure.

centralize database

2. Distributed Databases

Distributed databases are a set of connected databases that are stored on multiple systems and appear as a single database to users. In a distributed database, nodes are in different locations. Therefore, the overhead is higher. Unlike the centralized database system, distributed databases are stored in different sites and are connected via communication links. It is more reliable than centralized. Apache Cassandra, HBase, Ignite, etc are examples of distributed databases.

Distributed databases are of two types- Homogeneous and Heterogeneous. Homogenous Distributed Databases executes on the same operating system, uses the same application process, and carries the same hardware devices while Heterogeneous Distributed Databases execute on different operating systems under different application procedures, and carry different hardware devices.

Distributed Databases

3. Relational Databases

It is based on the relational data model, which stores data in the form of rows known as tuples and columns known as attributes, and together forms a table known as a relation. It uses query languages for storing, manipulating, as well as maintaining the data. In this model, all the data is stored in tabular form. So, every row is linked with another row.

Relational Database follows the ACID properties of a database where A is atomicity, C is consistency, I is integrity and D is durability. MySQL, Microsoft SQL Server, Oracle, etc are examples of Relational Databases.

Relational Databases

4. NoSQL Databases

NoSQL is also known as Not Only SQL database that is used for storing a wide range of data sets. It stores data not only in tabular form but in different ways. It is faster than SQL. The NoSQL database can easily analyze large-size unstructured data that can be stored in multiple virtual servers in the cloud.

Advantages of NoSQL database

The advantages of the NoSQL databases are given below:

  • High Availability
  • High Scalability
  • Has Big Data Capability
  • Performs Easy Replication
  • Has fast performance.

Types of NoSQL databases

There are four types of NoSQL databases which are given below:

  • Key-value: It stores every single item as a key (or attribute name) holding its value, together. Example - Riak, Redis.
  • Document-oriented: It is used to store data as JSON-like documents. The developers can store the data using the same document model format as used in the application code. Example - Couchbase MongoDB.
  • Graph: It is used for storing vast amounts of data in a graph-like structure. Example - Neo4J, Bigdata.
  • Wide-column: It is similar to the data represented in relational databases. In this, data is stored in columns instead of rows. Example - Cassandra, HBase.

Types of NoSQL databases

5. Cloud Databases

Clouds are also known as virtual environments, stores a huge amount of data either in a hybrid cloud, public or private cloud. It provides users with various cloud computing services along with cloud computing platforms.

Advantages of Cloud Databases

The advantages of the Cloud Databases are given below:

  • Has the ability to pay for storage capacity and bandwidth on a per-user basis
  • They provide scalability on-demand along with high availability.

Examples: Google Cloud SQL, Amazon Web Services, etc.

Cloud Databases

6. Object-oriented Databases

It contains data in the form of objects and classes. It uses object-oriented concept like encapsulation, inheritance, etc. This database is integrated with the programming language and has an automatic method of storage. The data and relationships are stored in a single structure known as an object. It is also known as Semantic Data Model. It contains both data member values and their operation under one roof.

Object-oriented Databases

7. Hierarchical Databases

It is based on the hierarchal model and the data is organized into a tree-like structure. It defines a parent/child relationship in such a way that it can not have too many relationships. It is the oldest data model. This database uses pointers to navigate between stored data. Data are stored as records that are connected through links. Each child record can have only one parent. On the other hand, each parent's record may contain records of multiple children.

Hierarchical Databases

8. Network Databases

This database involves complex database structures as it supports many-to-many relations. It follows the network data model and somewhat similar to the hierarchical model. It is designed with the concept of parents and children with their features and relationship. It is complicated because one record can be used as a key of the entire database. This database is mainly used on large digital computers due to its great efficiency.

Network Databases

9. Personal Databases

The personal database is simple in design and typically supports single-user database applications. They have few tables. This database involves only one computer and supports one user at a time. This database should only be used for applications that are not mission-critical. Data is collected and stored within personal computers. The data can be easily manageable, occupies less storage space as it is small in size.

Personal Databases

10. Operational Databases

These are generally designed to support high-volume transaction processing. Information related to the operations of an enterprise is stored inside this database. Data is stored with a functional and operational orientation so it has a complex structure. Its performance is low for analyzing queries. The data in the operational database is updated regularly. Operational Database allows you to simply view the archived data and modifies it in real-time.

Operational Databases

Conclusion

In this article, we discussed various types of databases available with their advantages and disadvantages. Among these, we will discuss relational databases in detail.