How to create a new database table using InstallSchema in Magento 2.

Here we will learn, How to create a database table by InstallSchema in Magento 2. In Magento 2.3.x and later versions, magento also provided the functionality to create a new table using Declarative Schema.

To know more about this, you can check our another blog for Create Tables in Magento 2.

We start by defining the app/code/Webkul/CreateTable/Setup/InstallSchema.php

<?php
namespace Webkul\CreateTable\Setup;

use Magento\Framework\Setup\InstallSchemaInterface;
use Magento\Framework\Setup\ModuleContextInterface;
use Magento\Framework\Setup\SchemaSetupInterface;
use Magento\Framework\DB\Ddl\Table;

class InstallSchema implements InstallSchemaInterface
{
    /**
     * Installs DB schema for a module
     *
     * @param SchemaSetupInterface $setup
     * @param ModuleContextInterface $context
     * @return void
     */
    public function install(SchemaSetupInterface $setup, ModuleContextInterface $context)
    {
        $installer = $setup;

        $installer->startSetup();

        $table = $installer->getConnection()
            ->newTable($installer->getTable('my_database_table'))
            ->addColumn(
                'entity_id',
                Table::TYPE_INTEGER,
                null,
                ['identity' => true, 'nullable' => false, 'primary' => true],
                'ID'
            )
            ->addColumn(
                'user_name',
                Table::TYPE_TEXT,
                null,
                ['nullable' => false, 'default' => ''],
                'User Name'
            )
            ->addColumn(
                'email',
                Table::TYPE_TEXT,
                null,
                ['nullable' => false, 'default' => ''],
                'User Email'
            )
            ->addColumn(
                'value',
                Table::TYPE_DECIMAL,
                '12,4',
                [],
                'Value'
            )
            ->setComment('About Your Table');
        $installer->getConnection()->createTable($table);

        $installer->endSetup();
    }
}

The install method is all that is required in above code. Within this method, we would add any relevant code we might have to create the tables and columns we need.

The addColumn method is the used to create column. It takes five parameters,
from column name, data type, column length, array of additional options,
and description.
Accepted column data types are:
TYPE_BOOLEAN, TYPE_SMALLINT, TYPE_INTEGER, TYPE_BIGINT, TYPE_FLOAT, TYPE_NUMERIC, TYPE_DECIMAL, TYPE_DATE, TYPE_TIMESTAMP, TYPE_DATETIME, TYPE_TEXT, TYPE_BLOB, TYPE_VARBINARY

Note: The module’s module.xml file must have setup_version to create database table using InstallSchema. To know steps to create module in Magento 2,  you can check our another blog for Create Hello World Module in Magento 2.

Now Open the Terminal/cmd and from the Magento’s root directory run the below command
php bin/magento setup:upgrade