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All changes to database schema have to take into account the upgrade process. While we do not plan on supporting upgrades between each and every minor schema revision, we have to ensure that upgrades between all released version of software are supported.
Upgrading the schema for a new feature
Submit all schema changes as an SQL code snippet (patch) located in the /neoconf/etc/database directory. Register a new patch in the database.xml file (in the same directory).
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As a developer of a new feature, your job is done!
Upgrading the schema to prepare for a new release
Before a release when database schema is decalred stable, a project commiter makes a decision to migrate the contents of the patches to the /neoconf/etc/database/schema.sql script.
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So project commiter manually integrates all the patches into the schema file, then updates the declared schema version but leaves the patches as they are!. They are used as is, for customers upgrading from any previous release, that is not installing a new system.
Notes for preparing schema for new release
Because this steps involves some manual steps, following these steps will remove much of the chance for user error.
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RequiredDatabaseVersion= Put N Here |
Remove the oldest release
We've decided (see here) to only carry over three releases worth of patches. As you freeze the schema for a new release, remove the patches the oldest release. This includes the versionOLDEST string and the patch node entries from database.xml, as well as the actual patch files.