[hibernate-issues] [Hibernate-JIRA] Commented: (HHH-6054) Support for discriminator-based multi-tenancy

[Jason Clawson (JIRA)]

    [ http://opensource.atlassian.com/projects/hibernate/browse/HHH-6054?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=44530#comment-44530 ] 

Jason Clawson commented on HHH-6054:
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To Damien's point... We have multitenency support in hibernate implemented using hibernate filters.  We are able to model the exact multitenent requirements Damien has described.  Some of our user permission discriminated data is based on a recursive oracle CONNECT BY query against a graph.

The only problem with our solution is that EntityManager.find(id) bypasses the filter because hibernate filters do not get applied to find() operations.  I asked about this on the mailing list and got the reply: "I am not going to change the way/places that filters are applied.  They work exactly as intended" and then referred me to version 4.1 that would feature "discriminator-based multi-tenency".  The multitency solution described here will not work for me, nor Damien and is too simple of a view on what multi-tenency means.

This is what multi-tenency means to me:
1) Separate 1 customer's data from another
2) Allow some users to see 1 or more customer's data.  They might be super admins that can see all customers, they might be sales people who can see a subset of customers.  They might have a network of hierarchical tenents as Damien described.
3) within a customer, restrict the data that a specific user can see based on their permissions.  This permissions query in my world is a complicated recursive query
4) be able to disable filters (allow all data) for a specific set of queries depending on need

Our solution using filters solves all of the above cases.  We have had to override EntityManager.find to do a query instead of the simple find operation in order to get the filter to activate.

Having a domain object protected by the customer filter is as easy as extending the CustomerDomainObject class.  Likewise, being protected by the user permissions filter is as easy as extending UserProtectedDomainObject.  The filters are additive and bound programmatically at startup.

> Support for discriminator-based multi-tenancy
> ---------------------------------------------
>
>                 Key: HHH-6054
>                 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-6054
>             Project: Hibernate Core
>          Issue Type: New Feature
>          Components: core
>            Reporter: Steve Ebersole
>              Labels: multi-tenancy
>             Fix For: 4.1.0
>
>
> Follow up on HHH-5697 to add support for discriminator based set ups.
> Considerations:
> # What is the design of this in the metadata?  
> ## At minimum we need to know the column to use for discrimination.
> ## Personally believe this should not be a attribute/property based.  Should just name a column to use.
> # We really should discover up front whether a {{SessionFactory}} contains any tenant data and require tenant identifier to be set in these cases.  
> ## Explicit.  The user passes us something saying that the {{SessionFactory}} involves multi tenancy
> ## Implied.  Checking the connection provider (based on current split there) can indicate schema-based multi-tenancy.  Checking all entities can imply the same for discriminator-based
> ## May need a way to allow user to tell us which approach to use.  That might be the explicit option.
> # Insert statements need to be altered to include the tenant identifier
> # All selects need to be altered to add predicate condition based on tenant identifier.  
> ## Allow switch to say whether this is done as a literal versus done as a JDBC parameter.  This has been requested couple of times in regards filters as well to deal with database partitions and database query optimizers that need the partition value to be a literal.
> All persistence context and second level cache related keys are already handled in the first phase.

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