Common Collections in several Databases

Hi, Within all of our databases we have common collections such as users, facilities etc. I was wondering if it is possible to have these linked across the databases, so amending the values in one (such as deleting a user) would amend it for access in all the databases. The problems stems from accessing the data in XQuery, where you can only access collections within the current database. Managing the data across several databases leaves too much room for human error if its done manually, but doing multiple queries on separate databases significantly affect performance Does anyone have ideas on how to combat this problem? Thanks Ryan Puddephatt

This sounds similar to “how do I maintain a list of valid users in a network?”. 2 possible solutions (depending on how you access the data). 1. have a central list of users that is queried to verify access rights 2. ensure that the valid list of users is updated simultaneously across the DBs

Mark, This is not actually what I’m looking for, I have collections within several databases that I want to make common via replication or linking, how easy is this to do? or is it even possible? Thanks Ryan

Looking at the documentation under “Replication Guide” it looks like replication may only be done at the DB level rather than collection level.

Mark, I’ve looked through the “Replication Guide” and this relates to the replication of a database in the case of the master failing, which is also not what I require. As I have said I have data that is common to all my databases, but if I amend that data in one database it will not be updated in all the other databases, this creates a major opportunity for inconsistent data. It also means that if I have 2GB worth of common data copied across 10 databases I then have 20GB of data. I thought, memory considerations aside, I could create a process that would take the data from a master and update that across all the databases, but this is not only a hack, but overwrites amended on that database. Is there anyway to link collections Thanks

I’m afraid that it is not currently possible to achieve a simple solution. Is it not possible to store the common data in a separate database and run 2 separate queries? You might be able to do this in the scope of global transactions if need be.

Thats a shame because relational databases allow links of collections/tables. Is this something that will be considered for a future release?

I was trying to avoid the two query scenario, to save on time and resources, but this is certainly a work around. Is there a way to query two databases in one query? Perhaps with a tamino specific function?

How do I go about doing this? Thanks for your help Ryan

From this reply it appears that you can’t query over multiple databases: For global transactions it depends on the programming language that you are using and the environment that you are working in. You will need to be using Tamino 4.4. COM+ was supported with the ActiveX + .NET APIs. I think that the Java API provides support for XA transactions. Note that you would typically only require global transactions for updates across DBs. For reads it may not be essential in a typical business environment unless you are supporting something like high volume customer activities.

Hi, This post is very informative, however I would like some specific information. If someone can help me then please send me a private message. Best Regards,