What are the Unique Benefits of Keys in DBMS?

According to a Salesforce report, “Almost 80% of Indian business leaders believe that data is critical for decision-making.” But are businesses able to use data efficiently? The majority of businesses struggle to manage and leverage data efficiently because of unstructured data formats and inaccurate data. Database Management Systems (DBMS) help in efficient data organization, storage, and management of data. You can access data records from the database by adding its unique key. Let’s understand the different types of keys in DBMS and how to use them.

How do Different Types of Keys in DBMS Help in Data Retrieval?

While database management systems are great for storing and organizing data, it can be difficult to manually search for data records in the system. Keys in DBMS are attributes (columns) that help locate or identify any unique record in the database. The following are different types of keys in DBMS and their use cases:

1. Primary Key

The primary key refers to a unique column or set of columns in a database. It helps identify all the data entries within different rows in the table. There is only one primary key in a table. 

 Consider the following example. You want to create an employee record. You start by creating a table in your database with the employee number (EMP_NUM), employee name (EMP_NAM), and address (EMP_ADD). To find the employee details through the employee number, the primary key will be EMP_NUM. Now, if you want to retrieve any data, such as the employee name or address, you can use the primary key to go to that column and search specific rows to collect data.

2. Candidate Key

A candidate key in DBMS is a column or a set of columns that helps to identify a tuple (row) in a table. There are multiple candidate keys in a table, of which only one primary key is selected. Considering the above example, (EMP_NUM), (EMP_ADD), and (EMP_NAM) are all candidate keys.

3. Super Key

A super key in DBMS comprises one or more keys (including the primary key) to uniquely identify records in a table. For example, a super key can be (EMP_NUM + EMP_NAM).

4. Foreign Key

Foreign keys are unique keys in DBMS that define the relationship between two tables. You can understand it as the column in one table pointing to the primary key or another table that helps link different tables. Taking the same example as above, if we create another table with an employee number, performance rating, and task completion percentage, the employee number will be considered the foreign key. It will link the first table (with employee name and address data) to the second table. So, you can check the employee’s name and address, their performance rating, and task completion percentage in one go.

5. Composite Key

A composite key in DBMS comprises two or more columns or attributes to uniquely identify rows. For example, (EMP_NAM) and (EMP_ADD) will be considered composite keys. 

6. Alternate Key

Alternate keys in DBMS are all keys other than primary keys. These types of keys are called secondary keys.

7. Unique Key 

A unique key in DBMS refers to a column or set of columns that uniquely identifies each row in a column and prevents duplicate data values in a table. 

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What is the Significance of Primary Keys in Database Management?

Primary keys in DBMS are unique keys that help identify each entry in a table. They also ensure that each table has unique data and prevent data redundancy. 

How are Foreign Keys Different From Other Types of Keys in DBMS?

The main difference between foreign keys and other keys in DBMS is their ability to establish links or relationships between two tables by referring to the primary key of the second table. However, other keys are used to only uniquely identify each record within the table. 

A foreign key can also contain duplicate values. However, the other types of keys in DBMS, such as primary key, candidate key, super key, and unique key, contain unique values. 

Can a Single Attribute be a Key in a Database Table?

Yes, a single attribute can be a key in a database table. A primary key uses a single attribute for data retrieval from a table. Even a foreign key uses a single column or attribute for establishing links between two tables. 

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What is the Importance of Maintaining Key Constraints in a Database System?

A single data error on a spreadsheet cost JP Morgan $6.2 billion. That is the massive impact faulty or inaccurate data can have on your business. Therefore, merely using data to make decisions is not enough. It is crucial for organizations to ensure data accuracy and security. However, a database management system stores millions of data records. So, how do you ensure the accuracy of each data point? Key constraints play a critical role in this. 

Key constraints are rules or limitations applied on a key or data column that ensure only a particular type of data can be stored in the database. Moreover, key constraints allow restricted operations on a data record. Hence, they ensure data accuracy and integrity. Some of the benefits of maintaining key constraints in a database management system are: 

1. Data Accuracy 

Keys in DBMS lay down guidelines or criteria for accepting the values belonging to a particular field. For example, a unique key constraint requires you to enter distinct values in specified columns. This means you can add only a certain type of data in a database system, hence preventing organizations from accidentally adding inaccurate data. Thus, it ensures excellent data quality. 

2. Data Consistency 

Foreign keys in DBMS ensure that the values in foreign key columns point to an existing record in the reference table. This helps define relationships between different tables and ensures data consistency.

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Data has huge significance for organizations. If you know how to efficiently manage and use data for the benefit of a business, you become a critical resource for any organization. However, you need to learn the latest skills, tools, and trends in data organization and data retrieval. Emeritus’ online information technology courses can help you gain practical experience and boost your career in data!

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