Magento 2 Implement Declarative Schema in Custom Module.
In this post, I’ll explain to you how to Implement Declarative Schema in the Custom Module.
To implement declarative schema in a custom module you need to create db_schema.xml file inside /Vendor/Modulename/etc and write the following code.
saveCopyzoom_out_map<?xml version="1.0"?>
<!--
/**
* Copyright © Magento, Inc. All rights reserved.
* See COPYING.txt for license details.
*/
-->
<schema xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Setup/Declaration/Schema/etc/schema.xsd">
<table name="vendor_tablename" resource="default" engine="innodb" comment="Vendor Modulename">
<column xsi:type="smallint" name="id" padding="6" unsigned="false" nullable="false" identity="true" comment="ID"/>
<column xsi:type="varchar" name="author_name" nullable="false" length="25" comment="Name"/>
<column xsi:type="varchar" name="email" nullable="false" length="25" comment="Email"/>
<column xsi:type="varchar" name="description" nullable="false" length="255" comment="Descrition"/>
<constraint xsi:type="primary" referenceId="PRIMARY">
<column name="id"/>
</constraint>
</table>
</schema>
Use for create and set table names.
<table> .. </table>
Use for create and set columns of the table.
<column> .. </column>
Use for set constraint as like primary key, foreign key, unique key, etc.
<constraint> .. </constraint>
Before running the upgrade command you need to add your schema to db_whitelist_schema.json file by running the following command:
php bin/magento setup:db-declaration:generate-whitelist --module-name=Vendor_Modulename
Now, there are db_whitelist_schema.json file will be created in /Vendor/Modulename/etc folder. Now, run
php bin/magento s:up
Now the table will be created inside the database.
In case if you want to rename a column, you will need to do few code changes in below line your db_schema.xml at appropriate column.
<column xsi:type="varchar" name="customer_email" onCreate="migrateDataFrom(email)" on_update="false" nullable="false" default="" comment="Customer Email"/>
Here, name="customer_email" is a new column name and onCreate="migrateDataFrom(email)" email is old column name.
Also, if you want to drop table, then you can either remove entire table node from an XML file or you can set a disabled attribute to true as like below line in your db_schema.xml
<table name="Vendor_Modulename" resource="default" engine="innodb" comment="Vendor Modulename" disabled="true">
..
</table>
That’s it.
I hope this post helped you to find what you were looking for. Bookmark it for your future reference. Do comment below if you have any other questions on that.
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