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DBMS Tutorial For Beginners: Everything You Need To Know

Before we begin exploring Database Management Systems (DBMS) in this DBMS tutorial, it is necessary to have a firm grasp of databases. 

Assume you work for a multinational firm with around a few thousand workers spread worldwide. Each employee will be assigned a unique employee ID, a job function, a manager, a ‘hire’ and ‘termination of agreement’ date, and a specific compensation amount. Since it isn’t feasible to create tables, categorise data, and write a thousand items on a piece of paper, databases were created in the 1960s.

Let us proceed with this DBMS tutorial so that you can grasp the basic concepts quickly.

What is a Database Management System(DBMS)?

Perhaps you have heard of MongoDB, Cassandra, OracleSQL, or MySQL. These are only a few of the many DBMS available. These programs enable you to save data, retrieve it, and conduct searches against databases.

A database is a digital representation of the ‘single long piece of paper’. It may be segmented, associated with another database, sorted according to various factors, and even compared to one another. 

Consider the following scenario: you want to analyse the salaries of individuals with the same job position and years of work experience. The only significant distinction is that they operate in different nations. You can accomplish this analysis using the DBMS or Database Management System. 

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Types of Database Management Systems

Database Management Systems can be classified into two types:

  • Relational Database Management Systems: A relational database is a data store that organises data into connected tables, as the name implies. Structured Query Language (SQL) lies at the heart of these systems since it is used to interface with and administer these databases, giving rise to their second moniker — SQL databases. 

In relational databases, data is stored in rows (records) and columns (attributes) that follow a specified model(a.k.a schema), ensuring that data is organised logically. Generally, there is one value for each property in each record, creating evident relationships between distinct data points.

  • Non-Relational Management Systems: A non-relational database is not tabular. It employs a variety of data models for saving, organizing, and obtaining information. They are referred to as NoSQL databases because they are not restricted to a table structure. 

They enable the storage of unstructured material such as texts, images, and various other file types. However, unlike in a relational database, data is not necessarily organised into rows and columns, as it would be in a flat-file system.

What are Keys in DBMS?

Keys are used to uniquely identify individual records or rows of data in the table. They also aid in the establishment and identification of links between table rows.

Different Types of Keys:

  • Primary Key: This key is used to identify a single instance of an object. Each schema has only one primary key. This key can be a value or a string that is not repeated more than once in the entire table. For example, an employee ID is the Primary Key for salary table or schema of employees. The employee ID is unique, and no two employees will have the same employee ID.
  • Foreign Key: Foreign keys are columns in a table used to refer to another table’s Primary key. A foreign key may also serve as the Primary key for another table.
  • Composite Key: When a Primary key has many attributes(more than one), it is referred to as a Composite key.
  • Candidate Key: Except the primary key, all other properties are considered candidate keys.
  • Super Key: A super key is a collection of attributes used to identify a tuple uniquely.

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Basic SQL commands for Managing Databases

SQL commands are a set of guidelines. It is used to exchange information with databases. Aside from that, it is also used to conduct certain activities, procedures, and data searches.

The most used SQL commands are explained below:

  • Data Definition Language(DDL): The DDL is used to create or edit database objects or the database’s structure, or to put it another way, to ‘define’ the objects or structure of the database.
  • CREATE: In the database, the command ‘CREATE’ creates new tables.
  • ALTER: The command ‘ALTER’ is used to add new columns or attributes to a table, or to modify the values of already-existing ones.
  • TRUNCATE: The command ‘TRUNCATE’ is used to remove all of the rows from a table and cleanse the available space in the particular schema you are working with.
  • DROP: The ’DROP’ command is used to remove or ‘DROP’ the structure and records that have been stored in the schema.
  • Data Manipulation Language(DML): The DML is used to modify databases per the user’s wishes by performing queries in the database. These are the most often used commands while dealing with databases. Data may be changed by adding or removing values from the database and altering values already present in the database.
    • INSERT: This command is used to enter or ‘INSERT’ data into a row of a table or schema.
    • UPDATE: This command is used to ‘UPDATE’ the column value of a table or schema.
    • DELETE: This command removes or ‘DELETE’ rows from a table. The DELETE command can be combined with the ‘WHERE’ command to delete more than one row.
  • Data Control Language(DCL): The DCL determines how users may access information stored in a database. For example, if a database has 50 users working on it, the Database Administrator may give or revoke access to certain areas of the database to the engineers.
    • GRANT: Access rights provide user access to a database using the ‘GRANT’ command.
    • REVOKE: It is basically the opposite of the ‘GRANT’ command. It removes a user’s permissions from one or more schemas or tables.
  • Transaction Control Language(TCL): The TCL is used to ensure that the database remains consistent and to handle the transactions that are initiated by commands of the Data Manipulation Language(DML).
    • COMMIT: This command is used to save the current state of a database after the required queries have been executed.
    • ROLLBACK: This command is used to return to the point of all unsaved changes in the schema.
    • SAVEPOINT: This command is used to roll back to a certain point in time without having to roll back the whole transaction in its entirety.

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Conclusion

The need for highly skilled data-oriented employees is increasing with the proliferation of technological advancements in business. Because of the increased demand, the rivalry is becoming fiercer. Data scientists and analysts with a solid foundation in data science are in high demand by both large and small firms. They must stay updated with the data management systems on the market.

This database tutorial is just the beginning of your learning journey. With upGrad’s Master of Science in Data Science, you can deep dive into the world of data science. The course is offered in partnership with IIIT-B and Liverpool John Moore’s University, one of India’s leading research institutes. 

Students get the opportunity to connect with professionals in the field and gain knowledge and skills in cutting-edge technology and industry trends by participating in hands-on learning activities and sessions with their teachers.

What are the eligibility criteria for the Master of Data Science Program from upGrad?

A bachelor's degree with a minimum grade point average of at least 50 percent is required for admission. This course may be taken by anybody, regardless of their level of coding experience.

What is DBMS?

A database management system (or DBMS) is a computerised data storage system.

How many specialisations does upGrad’s Master of Data Science Program offer?

The program offers six specialisations in total.

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