How do I replace JDatabase on Joomla 4 or 6?

JDatabase is a Joomla 3 global class. Joomla 4 still has an alias. Joomla 5 needs the Behaviour – Backward Compatibility plugin. Native Joomla 6 does not load that alias — you get Class "JDatabase" not found. Use Joomla\Database\DatabaseDriver. Add a use statement for Joomla\Database\DatabaseDriver. Replace every JDatabase with the short class name from that use line. Disable Behaviour – Backward Compatibility on a Joomla 5 staging site. If it fatals, this class is still in the code.

What error does JDatabase throw after a Joomla upgrade?

Class "JDatabase" not found. Class 'JDatabase' not found. Failed to open stream: JDatabase

Why does JDatabase class name break after migrating from Joomla 3?

JDatabase is a Joomla 3 global class. Joomla 4 still has an alias. Joomla 5 needs the Behaviour – Backward Compatibility plugin. Native Joomla 6 does not load that alias — you get Class "JDatabase" not found. People notice: white screen after disabling compatibility plugin, class not found on Joomla 6, works on Joomla 5 until I turn off backward compatibility.

JDATABASE-CLASS-001

JDatabase

JDatabase class name

JDatabase is a Joomla 3 global class. Joomla 4 still has an alias. Joomla 5 needs the Behaviour – Backward Compatibility plugin. Native Joomla 6 does not load that alias — you get Class "JDatabase" not found.

JDatabase → Joomla\Database\DatabaseDriver

Dies at Joomla 5 → 6J3: Works nativelyJ4: Alias (old name still resolves)J6: Removed — fatalBC plugin: covers the class nameMechanical renameDatabase API

What you will see

Class "JDatabase" not found
Class 'JDatabase' not found
Failed to open stream: JDatabase

Symptoms people search

white screen after disabling compatibility plugin · class not found on Joomla 6 · works on Joomla 5 until I turn off backward compatibility

Replace this code

Swap JDatabase for Joomla\Database\DatabaseDriver.

Joomla 3

Remove or stop calling this

JDatabase::getInstance();
// or new JDatabase()

Joomla 4 / 6

Use this instead

use Joomla\Database\DatabaseDriver;

// Call the namespaced class. Do not keep the J prefix.

How to fix it

1Add a use statement for Joomla\Database\DatabaseDriver.
2Replace every JDatabase with the short class name from that use line.
3Disable Behaviour – Backward Compatibility on a Joomla 5 staging site. If it fatals, this class is still in the code.

Also known as

JDatabase · Joomla\Database\DatabaseDriver · class alias · J prefix

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JDatabase

What you will see

Symptoms people search

Replace this code

How to fix it

Also known as

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