What are Patches in Magento 2?

Patches in Magento 2 are used to modify database schema or data during module installation or upgrade.

Magento introduced the patch system to replace the older Install/Upgrade scripts such as InstallSchema.php, UpgradeSchema.php, InstallData.php, and UpgradeData.php.

Patches provide a more modular and trackable way to apply database changes.

Types of Patches in Magento 2

Magento provides two main types of patches.

• Schema Patch → Used to modify database structure.
• Data Patch → Used to insert or update data in database tables.

What is a Schema Patch?

A Schema Patch is used to modify the database structure, such as creating tables, adding columns, or modifying indexes.

Schema patches implement the SchemaPatchInterface.

Example: Create a Schema Patch

Suppose we want to create a custom table in the database.

1. Create Schema Patch File

(File: app/code/VendorName/ModuleName/Setup/Patch/Schema/CreateCustomTable.php)

What is a Data Patch?

A Data Patch is used to insert or update data in the database.

Typical use cases include:

• Adding default configuration values
• Creating CMS pages or blocks
• Inserting default records
• Updating existing data

Data patches implement the DataPatchInterface.

Example: Create a Data Patch

Suppose we want to insert default data into the custom table.

1. Create Data Patch File

(File: app/code/VendorName/ModuleName/Setup/Patch/Data/AddSampleData.php)

How Magento Executes Patches

When the following command is executed:

Magento scans the Setup/Patch directory and executes patches that have not yet been applied.

Executed patches are recorded in the patch_list table in the database.

Difference Between Schema Patch and Data Patch

• Schema Patch modifies database structure.
• Data Patch inserts or updates database data.
• Schema Patch implements SchemaPatchInterface.
• Data Patch implements DataPatchInterface.

Best Practices

• Use Schema Patches only for database structure changes.
• Use Data Patches for inserting or updating data.
• Keep patches small and focused on a single change.
• Avoid modifying existing patches once deployed.