Difference between Centralized Database and Distributed Database

1. Centralized Database: 

A centralized database is basically a type of database that is stored, located as well as maintained at a single location only. This type of database is modified and managed from that location itself. This location is thus mainly any database system or a centralized computer system. The centralized location is accessed via an internet connection (LAN, WAN, etc). This centralized database is mainly used by institutions or organizations. 

Advantages:

• Since all data is stored at a single location only thus it is easier to access and coordinate data.
• The centralized database has very minimal data redundancy since all data is stored in a single place.
• It is cheaper in comparison to all other databases available.

Disadvantages:

• The data traffic in the case of a centralized database is more.
• If any kind of system failure occurs in the centralized system then the entire data will be destroyed.

2. Distributed Database: 

A distributed database is basically a type of database which consists of multiple databases that are connected with each other and are spread across different physical locations. The data that is stored in various physical locations can thus be managed independently of other physical locations. The communication between databases at different physical locations is thus done by a computer network. 

Advantages:

• This database can be easily expanded as data is already spread across different physical locations.
• The distributed database can easily be accessed from different networks.
• This database is more secure in comparison to a centralized database.

Disadvantages:

• This database is very costly and is difficult to maintain because of its complexity.
• In this database, it is difficult to provide a uniform view to users since it is spread across different physical locations.

Difference between Centralized database and Distributed database: 

S.NO.	Basis of Comparison	Centralized database	Distributed database
1.	Definition	It is a database that is stored, located as well as maintained at a single location only.	It is a database that consists of multiple databases which are connected with each other and are spread across different physical locations.
2.	Access time	The data access time in the case of multiple users is more in a centralized database.	The data access time in the case of multiple users is less in a distributed database.
3.	Management of data	The management, modification, and backup of this database are easier as the entire data is present at the same location.	The management, modification, and backup of this database are very difficult as it is spread across different physical locations.
4.	View	This database provides a uniform and complete view to the user.	Since it is spread across different locations thus it is difficult to provide a uniform view to the user.
5.	Data Consistency	This database has more data consistency in comparison to distributed database.	This database may have some data replications thus data consistency is less.
6.	Failure	The users cannot access the database in case of database failure occurs.	In a distributed database, if one database fails users have access to other databases.
7.	Cost	A centralized database is less costly.	This database is very expensive.
8.	Maintenance	Ease of maintenance because the whole of the data and information is available at a single location and thus, easy to reach and access.	It is difficult to maintain because of the distribution of data and information at varied places. So, there is a need to check for data redundancy issues and how to maintain data consistency.
9.	Efficient	A centralized database is less efficient as data finding becomes quite complex because of the storing of data and information at a particular place.	A distributed database is more efficient than a centralized database because of the splitting up of data at several places which makes data finding simple and less time-consuming.
10.	Response Speed	The response speed is more in comparison to a distributed database.	The response speed is less in comparison to a centralized database.
11.	Advantages	Integrity of data Security Easy access to all information Data is easily portable	High performance because of the division of workload. High availability because of the readiness of available nodes to do work. Independent nodes and better control over resources
12.	Disadvantages	Data searching takes time In case of failure of a centralized server, the whole database will be lost. If multiple users try to access the data at the same time then it may create issues.	It is quite large and complex so difficult to use and maintain. Difficult to provide security Issue of data integrity Increase in storage and infrastructure requirements Handling failures is a quite difficult task
13.	Examples	A desktop or server CPU A mainframe computer.	Apache Ignite Apache Cassandra Apache HBase Amazon SimpleDB Clusterpoint FoundationDB.