EDUCBA

EDUCBA

MENUMENU
  • Free Tutorials
  • Free Courses
  • Certification Courses
  • 600+ Courses All in One Bundle
  • Login
Home Software Development Software Development Tutorials MariaDB Tutorial MariaDB alter table
Secondary Sidebar
MariaDB Tutorial
  • MariaDB
    • MariaDB Versions
    • MariaDB? list users
    • MariaDB Commands
    • MariaDB odbc
    • MariaDB Workbench
    • MariaDB for windows
    • MariaDB Server
    • MariaDB? Data Types
    • MariaDB? boolean
    • MariaDB phpMyAdmin
    • MariaDB Mysqldump
    • MariaDB Java Connector
    • MariaDB insert
    • MariaDB UPDATE
    • MariaDB? rename column
    • MariaDB AUTO_INCREMENT
    • MariaDB Timezone
    • MariaDB GROUP_CONCAT
    • MariaDB wait_timeout
    • MariaDB MaxScale
    • MariaDB? with
    • MariaDB GUI
    • MariaDB? create?table
    • MariaDB? SHOW TABLES
    • MariaDB alter table
    • MariaDB List Tables
    • MariaDB JSON Functions
    • MariaDB Foreign Key
    • MariaDB? trigger
    • MariaDB Grant All Privileges
    • MariaDB Select Database
    • MariaDB? create database
    • MariaDB Delete Database
    • MariaDB Join
    • MariaDB JSON
    • MariaDB? show databases
    • MariaDB List Databases
    • MariaDB Functions
    • MariaDB? TIMESTAMP
    • MariaDB create user
    • MariaDB add user
    • MariaDB Max Connections
    • MariaDB show users
    • MariaDB Delete User
    • MariaDB? change user password
    • MariaDB? change root password
    • MariaDB reset root password
    • MariaDB IF
    • MariaDB bind-address
    • MariaDB Transaction
    • MariaDB Cluster
    • MariaDB Logs
    • MariaDB Encryption
    • MariaDB? backup
    • MariaDB Replication
    • MariaDB max_allowed_packet
    • MariaDB? performance tuning
    • MariaDB export database
    • MariaDB? import SQL

MariaDB alter table

MariaDB alter table

Introduction to MariaDB alters table.

MariaDB provides alter table functionality to the user, in which we can change the structure of existing tables. For example, we can add columns into the specified table or delete a column from the table, create or delete indexes; we can change the datatype of the existing column, rename column name, and we can also change the storage engine of the table. If we use another connection for the alter command, if the metadata lock is active, then the alter statement will wait until the lock is released. When we need to add a unique index on a column that specified duplicate values, then alter command shows an error message, and statement execution will be stopped. The alter command is also used to rename the table name.

Syntax:

Start Your Free Software Development Course

Web development, programming languages, Software testing & others

alter table table_name add new colm name column structure or definition [before colm name | after colm name];

Explanation:

  • In the above syntax, we used the alter table command to add a new column name into the table.
  • In this syntax, table name means specified table name and add the keyword used to add a new column into the specified table with column definition or structure that means null or not null etc.
  • Here before column name and after column name is an optional part of this syntax, and it is used to indicate where in the table we need to create the column.

How to alter the table in MariaDB?

  • Basically, alter table command comes under the data definition language.
  • In MariaDB, alter table statements are useful to change the structure of tables, or we can change the definition of columns. Altering tables in the column is a big task, or we can say this is not very difficult; but some database developers are not familiar with the alter command, but with the help of alter command syntax, we can easily perform different operations.
  • We can use different clauses to alter table statements.

Examples of MariaDB alter table.

Given below are the examples of MariaDB alter table:

First, we need a table to perform different operations of the alter table command, so by using the following statement, we can create a table.

Code:

create table stud1(
stud_id int auto_increment,
stud_name varchar(255) not null,
address varchar(255) not null,
primary key (stud_id));

Explanation:

  • In the above example, we created a table name as a stud1 with different attributes. The stud1 table has a 3 column as shown in the above statement.
  • The stud_id is an integer column with auto_increment property, so MariaDB will automatically increment a sequential number when we insert a new row into the table. In addition, the stud_id column is a primary key specified by using the primary key constraint as shown at the end of the statement, and the primary key constraint is useful to identify unique rows in the table.
  • stud_name is a variable-length character with a maximum size of the character. The stud_name has a not-null constraint that means we cannot insert null values into this column.
  • The address is a variable-length character with a maximum size of the character, and it also has a not-null constraint.

Output:

MariaDB alter table 1

After that, we insert some records into the stud1 table by using insert into statement. The final definition of the stud1 table is shown in the below snapshot.

Code:

select * from stud1;

All in One Software Development Bundle(600+ Courses, 50+ projects)
Python TutorialC SharpJavaJavaScript
C Plus PlusSoftware TestingSQLKali Linux
Price
View Courses
600+ Online Courses | 50+ projects | 3000+ Hours | Verifiable Certificates | Lifetime Access
4.6 (86,198 ratings)

Output:

MariaDB alter table 2

Example #1

Change Column.

Suppose we need to modify the stud_id column definition, in which we modify the data type of the stud_id column by using the following statement.

Code:

ALTER TABLE stud1 MODIFY stud_id BIGINT UNSIGNED AUTO_INCREMENT;

Explanation:

  • In the above example, we use the alter table command to modify the data type of the stud_id column, here we add a new data type BIGINT UNSIGNED instead of INT data type as shown in the above statement.
  • The final output of the above query we illustrate by using the following snapshot.

Output:

MariaDB alter table 3

Example #2

Change Column.

In this type of example, we can change the column as follows.

Code:

ALTER TABLE stud1 ALTER address SET DEFAULT 'Mumbai';

Explanation:

  • In the above example, we alter the address column; in this example, we set the default value of the address column as Mumbai, as shown in the above statement.
  • The final output of the above query we illustrate by using the following snapshot.

Output:

Change Column

Example #3

Rename column of Table.

In this type of example, we can change the table’s column name by using the alter table command as follows.

Code:

ALTER TABLE stud1 RENAME column stud_id TO roll_no;

Explanation:

  • In the above example, we use the rename column command to change the column name as in this example; we changed the column name of stud_id to roll_no by using the alter table command with rename column clause as shown in the above statement.
  • The final output of the above query we illustrate by using the following snapshot.

Code:

select * from stud1;

Output:

MariaDB alter table 5

In the above screenshot, we can see the updated column name.

Example #4

Drop by default clause.

Code:

ALTER TABLE stud1 ALTER address DROP DEFAULT

Explanation:

  • In the above example, we use the alter table command to drop the default value column. In this example, we drop the default value of the address column as shown above example.
  • The final output of the above query we illustrate by using the following snapshot.

Output:

Drop by default clause

Example #5

Rename Table Name.

We can also change the table name by using the following statement.

Code:

ALTER TABLE stud1 RENAME TO college_stud;

Explanation:

  • In the above example, we change the table name by using rename keyword here; we change table name stud1 to college_stud as shown in the above statement.
  • The final output of the above query we illustrate by using the following snapshot.

Output:

Rename

In this way, similarly, we can perform add primary key, drop primary key, add foreign key, drop foreign key, add an index, drop index etc.

Recommended Articles

This is a guide to MariaDB alter table. Here we discuss the introduction, how to alter table in MariaDB? and examples, respectively. You may also have a look at the following articles to learn more –

  1. MariaDB Foreign Key
  2. MariaDB Commands
  3. MariaDB UPDATE
  4. Database Management Software
Popular Course in this category
SQL Training Program (7 Courses, 8+ Projects)
  7 Online Courses |  8 Hands-on Projects |  73+ Hours |  Verifiable Certificate of Completion
4.5
Price

View Course
0 Shares
Share
Tweet
Share
Primary Sidebar
Footer
About Us
  • Blog
  • Who is EDUCBA?
  • Sign Up
  • Live Classes
  • Corporate Training
  • Certificate from Top Institutions
  • Contact Us
  • Verifiable Certificate
  • Reviews
  • Terms and Conditions
  • Privacy Policy
  •  
Apps
  • iPhone & iPad
  • Android
Resources
  • Free Courses
  • Java Tutorials
  • Python Tutorials
  • All Tutorials
Certification Courses
  • All Courses
  • Software Development Course - All in One Bundle
  • Become a Python Developer
  • Java Course
  • Become a Selenium Automation Tester
  • Become an IoT Developer
  • ASP.NET Course
  • VB.NET Course
  • PHP Course

ISO 10004:2018 & ISO 9001:2015 Certified

© 2022 - EDUCBA. ALL RIGHTS RESERVED. THE CERTIFICATION NAMES ARE THE TRADEMARKS OF THEIR RESPECTIVE OWNERS.

EDUCBA
Free Software Development Course

C# Programming, Conditional Constructs, Loops, Arrays, OOPS Concept

*Please provide your correct email id. Login details for this Free course will be emailed to you

By signing up, you agree to our Terms of Use and Privacy Policy.

EDUCBA Login

Forgot Password?

By signing up, you agree to our Terms of Use and Privacy Policy.

EDUCBA
Free Software Development Course

Web development, programming languages, Software testing & others

*Please provide your correct email id. Login details for this Free course will be emailed to you

By signing up, you agree to our Terms of Use and Privacy Policy.

EDUCBA

*Please provide your correct email id. Login details for this Free course will be emailed to you

By signing up, you agree to our Terms of Use and Privacy Policy.

Let’s Get Started

By signing up, you agree to our Terms of Use and Privacy Policy.

This website or its third-party tools use cookies, which are necessary to its functioning and required to achieve the purposes illustrated in the cookie policy. By closing this banner, scrolling this page, clicking a link or continuing to browse otherwise, you agree to our Privacy Policy

Loading . . .
Quiz
Question:

Answer:

Quiz Result
Total QuestionsCorrect AnswersWrong AnswersPercentage

Explore 1000+ varieties of Mock tests View more