Definition for SQL

Structured query language (SQL) is a programming language for storing and processing information in a relational database. A relational database stores information in tabular form, with rows and columns representing different data attributes and the various relationships between the data values. You can use SQL statements to store, update, remove, search, and retrieve information from the database. You can also use SQL to maintain and optimize database performance.

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In this article,we are going to discuss how to create a table in a database,insert the values in the table.First start the mariadb server,follow the steps in the article if mariadb is not installed in your system.Refer the Installation guide for mariadb is below link.

https://opendiaryofgowthamg.wordpress.com/2024/02/14/installation-mariadb/

After opening the terminal,we need to know the databases presented in mariadb.So that,use..,

SHOW DATABASES;

It will show the available databases.Next we need to create a database and switch into that new database.Using Capital letters for keywords is a good practice in SQL.

CREATE DATABASE database_name;
USE database_name;

Now,we created a database and switched into it.We need to create a table for this database.

CREATE TABLE table_name (Sno int(3),Name varchar (30),Mobile No int (13));

We created a new table with three columns.
Sno has Integer datatype and it can stores upto 3 integer values (i.e up-to 999).
Name has varchar datatype and it stores up-to 30 Characters.
Mobile No has Integer datatype and stores up-to 13 integer value

DESC table_name;

This command allow us to view the description of that table.Practice is the database name which i was created and testing is the name i given to this table.We will discuss about NULL,Key,Default,Extra are in the later sessions.

This is how we create a simple basic table.Let’s see hoe to insert values to this table.

INSERT INTO table_name values (1,"person_1",1231231231);
INSERT INTO table_name values (2,"person_2",97979797),(3,"person_3",34343434),(4,'person_4',456789123);

First line shows,inserting only a single row data to the table.Whereas,second one shows multi data insertion to the table.We can use either Double Quote (” “) or Single Quote (‘ ‘) to the Character datatype.

Let’s see how to view this table entirely or only a specific column.

SELECT * FROM table_name;
SELECT column_name FROM table_name;

The first image shows the full table contents.
Second image shows only a particular column named “books”.

EXIT;

Exit from mariadb.

We will discuss how to edit,update the table in next article.

That’s it..!

Definition for SQL

Structured query language (SQL) is a programming language for storing and processing information in a relational database. A relational database stores information in tabular form, with rows and columns representing different data attributes and the various relationships between the data values. You can use SQL statements to store, update, remove, search, and retrieve information from the database. You can also use SQL to maintain and optimize database performance.

---

In this article,we are going to discuss how to create a table in a database,insert the values in the table.First start the mariadb server,follow the steps in the article if mariadb is not installed in your system.Refer the Installation guide for mariadb is below link.

https://opendiaryofgowthamg.wordpress.com/2024/02/14/installation-mariadb/

After opening the terminal,we need to know the databases presented in mariadb.So that,use..,

SHOW DATABASES;

It will show the available databases.Next we need to create a database and switch into that new database.Using Capital letters for keywords is a good practice in SQL.

CREATE DATABASE database_name;
USE database_name;

Now,we created a database and switched into it.We need to create a table for this database.

CREATE TABLE table_name (Sno int(3),Name varchar (30),Mobile No int (13));

We created a new table with three columns.
Sno has Integer datatype and it can stores upto 3 integer values (i.e up-to 999).
Name has varchar datatype and it stores up-to 30 Characters.
Mobile No has Integer datatype and stores up-to 13 integer value

DESC table_name;

This command allow us to view the description of that table.Practice is the database name which i was created and testing is the name i given to this table.We will discuss about NULL,Key,Default,Extra are in the later sessions.

This is how we create a simple basic table.Let’s see hoe to insert values to this table.

INSERT INTO table_name values (1,"person_1",1231231231);
INSERT INTO table_name values (2,"person_2",97979797),(3,"person_3",34343434),(4,'person_4',456789123);

First line shows,inserting only a single row data to the table.Whereas,second one shows multi data insertion to the table.We can use either Double Quote (” “) or Single Quote (‘ ‘) to the Character datatype.

Let’s see how to view this table entirely or only a specific column.

SELECT * FROM table_name;
SELECT column_name FROM table_name;

The first image shows the full table contents.
Second image shows only a particular column named “books”.

EXIT;

Exit from mariadb.

We will discuss how to edit,update the table in next article.

That’s it..!

Let’s know the installation of mariadb in debian.

sudo apt update
sudo apt install mariadb-server mariadb-client

First of all,we need to update the package manager and then type the install command.

Here we are going to install two packages i.e.., for server side and client side.You can skip the “mariadb-client” if you don’t need.

sudo systemctl status mariadb.service

Using this command,we can check the status of mariadb.Refer the image.

Now,we successfully done with the installation.After this we need to set a password to the root user.Because,by default the root user doesn’t have any password.So,we need to use this command..,

sudo mysql_secure_installation

Simply,press enter and then press ‘N’ next press ‘Y’ for further steps.

Also,you can create a new user.Let’s see how to create a new user.

CREATE USER 'your_username'@'localhost' IDENTIFIED BY 'your_password';

GRANT ALL PRIVILEGES ON *.* TO 'your_username'@'localhost' WITH GRANT OPTION;

FLUSH PRIVILEGES;

User has been created.

Let’s enter into mariadb.

mariadb -u your_username -p

NOTE: Don’t pass “@localhost” here.Simply pass username only.

Now,enter the created password.

If the output displayed like this,you were done…

SHOW DATABASES;

Here,we can see the databases.

We can discuss it later on MySQL topics.

EXIT;

Exit from mariadb.

sudo nano /etc/mysql/mariadb.conf.d/50-server.cnf

Getting this configuration file,we can change some configuration.

NOTE :

After configure,we must restart the mariadb.

sudo systemctl start mariadb.service
sudo systemctl stop mariadb.service
sudo systemctl enable mariadb.service
sudo systemctl disable mariadb.service
sudo systemctl restart mariadb.service

We can use these commands as per our convenience like we discussed in Apache installation.

That’s it..!

Let’s know the installation of mariadb in debian.

sudo apt update
sudo apt install mariadb-server mariadb-client

First of all,we need to update the package manager and then type the install command.

Here we are going to install two packages i.e.., for server side and client side.You can skip the “mariadb-client” if you don’t need.

sudo systemctl status mariadb.service

Using this command,we can check the status of mariadb.Refer the image.

Now,we successfully done with the installation.After this we need to set a password to the root user.Because,by default the root user doesn’t have any password.So,we need to use this command..,

sudo mysql_secure_installation

Simply,press enter and then press ‘N’ next press ‘Y’ for further steps.

Also,you can create a new user.Let’s see how to create a new user.

CREATE USER 'your_username'@'localhost' IDENTIFIED BY 'your_password';

GRANT ALL PRIVILEGES ON *.* TO 'your_username'@'localhost' WITH GRANT OPTION;

FLUSH PRIVILEGES;

User has been created.

Let’s enter into mariadb.

mariadb -u your_username -p

NOTE: Don’t pass “@localhost” here.Simply pass username only.

Now,enter the created password.

If the output displayed like this,you were done…

SHOW DATABASES;

Here,we can see the databases.

We can discuss it later on MySQL topics.

EXIT;

Exit from mariadb.

sudo nano /etc/mysql/mariadb.conf.d/50-server.cnf

Getting this configuration file,we can change some configuration.

NOTE :

After configure,we must restart the mariadb.

sudo systemctl start mariadb.service
sudo systemctl stop mariadb.service
sudo systemctl enable mariadb.service
sudo systemctl disable mariadb.service
sudo systemctl restart mariadb.service

We can use these commands as per our convenience like we discussed in Apache installation.

That’s it..!