[OAK-597] Uniqueness validator instead of unique index

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Won't Fix
• Component/s: core, query
• Assignee: Unassigned
• Reporter: Thomas Mueller
• Created: 30/Jan/13 13:15
• Updated: 10/Mar/15 15:56
• Resolved: 10/Mar/15 15:56

Description

We currently have a few unique indexes that ensure only one node may exist for a given node type / property name / property value combination (for example the jcr:uuid needs to be unique).

While this works, I see some problems with this approach:

• Indexes might be removed by an admin or they might not be available due to misconfiguration.

• It (slightly) complicates the index implementation.

• The index needs to do something that is not obvious (the index has to act like a constraint / validator). Updating an index can fail for different reasons that have a different meaning: updating the index might fail due to duplicate key (which is not recoverable), and it might fail due to a conflict (which is recoverable).

Instead of using unique indexes, I propose to use a validator instead. The validator can internally run a query to check if such a value already exists.

Issue Links

• is related to: OAK-270 Enforce uniqueness of jcr:uuid