The main difference between data redundancy and data inconsistency is that data redundancy is a condition that occurs when the same piece of data exists in multiple places in the database whereas data inconsistency is a condition that occurs when the same data exists in different formats in multiple tables.

A database is a collection of data. DBMS (Database Management System) is a software that helps to manage databases. Introduced around the year 1960, it can handle a large collection of data. Moreover, it helps to create, retrieve, update and delete data easily. DBMS allows multiple users to access data simultaneously and provides security to the data. Data redundancy and data inconsistency are two terms related to DBMS.

Key Areas Covered

1. What is Data Redundancy
      – Definition, Functionality
2. What is Data Inconsistency
     – Definition, Functionality
3. What is the Difference Between Data Redundancy and Data Inconsistency
     – Comparison of Key Differences

Key Terms

Data Inconsistency, Data Redundancy

What is Data Redundancy

Data redundancy refers to the same data located in multiple places in the database. It clusters the database with unneeded information. It also makes data retrieving less efficient. Furthermore, data redundancy consumes more resources in the database. Over time, data redundancy makes database corruption, causing the data to be unusable.

For example, assume a table in the school database. It has a table called student as follows.

The student 1 and 2 are learning from teacher P, and student 3 and 4 are learning from teacher Q. Here, the teacher_id and teacher_name repeats twice. Instead, the teacher_id and teacher name can be stored into a separate table. New student table and the teacher table are as follows.

The solution is to data redundancy is normalization. It reduces data redundancy and makes data more meaningful.

What is Data Inconsistency

Data inconsistency refers to a situation of keeping the same data in different formats in two different tables or a situation where it requires to match the data between tables. However, this can cause one table in the database to have the correct value and the remaining tables to be different. It can also cause unreliable and meaningless information. Moreover, it is difficult to reduce data inconsistency.

For instance, assume a hospital database.  Changing the address of one patient can affect many other tables. Only one record will have correct data while the others will have false data. Hence, this is data inconsistency. It causes the hospital management to check multiple records to obtain the correct patient address. It happens because the same data residing in multiple places are not updated. Using adequate constraints within the database is a solution to prevent data inconsistency.

Relationship Between Data Redundancy and Data Inconsistency

• Data redundancy can cause data inconsistency.

Difference Between Data Redundancy and Data Inconsistency

Definition

Data redundancy is a condition that occurs within a database or data storage technology in which, you can find the same piece of data in two or more separate places. Whereas, data inconsistency is a condition that occurs between tables when we keep similar data in different formats in two different tables, or when matching of data between tables is a must. These definitions, thus, explain the main difference between data redundancy and data inconsistency.

Prevention

Prevention is the other main difference between data redundancy and data inconsistency. Normalization helps to minimize data redundancy. However, using constraints on the database helps to prevent data inconsistency.

Conclusion

In general, data redundancy and data inconsistency are two terms related to DBMS. The main difference between data redundancy and data inconsistency is that data redundancy is a condition that occurs when the same piece of data exists in multiple places in the database whereas data inconsistency is a condition that occurs when the same data exists in different formats in multiple tables.

Reference:

1. “What Is Data Redundancy?” Reference, IAC Publishing, Available here.
2. “What Is the Definition of Data Inconsistency?” Reference, IAC Publishing, Available here.

Image Courtesy:

1. “1954920” (CC0) via Pixabay

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