What is this article for
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This article shows you how to make DB structure or data manipulations for new CB releases, customization project releases and sharing code via VCS.
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There is a directory containing PHP files that handle any necessary upgrade steps.
That directory is in appDir/helpers/updates for core code and customizationDir/updates for customization code
Each of these files use version numbers as file names (not necessarily CB release version numbers)
The application keeps track of the highest version number that got processed successfully.
During app initialisation, the app lists the files and loads new files in the right order
On Exceptions, the upgrade procedure halts, a notice appears on the CB dashboard and upgrade scripts won't run again until the situation is rectified
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The location for customization upgrade scripts is in customizationDir/updates.
In table #__configbox_system_vars you find the last processed file in latest_customization_update_version.
On failures, the app logs errors in configbox_upgrade_errors and flags the failure in system vars key failed_update_detected (same as for core issues)
On failures, the app will not try upgrade scripts again on subsequent page loads until the situation is rectified.
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