How many Main Tables can I have? Is there a limit?

[Former Member]

I have this question burined in another post but will bring it out into it's own post now...

I know that 7.1 allows me to have MULTIPLE main tables. But - how many is too many in a repository? Can I have 20 main tables? Has anyone out there had that many Main tables in the same Repository?

[Former Member · Accepted solution]

Thanks for your input. Actuallly - what I have are some Mapping Tables that need to be maintained and then fed into BW...

The info is currently handled in Spreadsheets - not a viable long term solution. The data does not exist in any ERP system.

Rather than put these tables into ERP boxes we want to put them into MDM - then set up folks to be able to maintain then using Data Manager and then have them syndicated into BW.

I think I need to make them all seperate Main Tables because they really do not have any fields or information in common.

This is part of a pilot project for our company. We will also be working on a more standard project - deploying later - for Materials. I would expect there to only have One Main table with some Look up tables - more of a standard use of MDM.

So - the question is still - has anyone worked with a Repository with 5, 10 15, 20 or more Main Tables?

[Former Member · Accepted solution]

Hi Beth,

The primary purpose of having multiple main tables is two master objects which are linked.

For example if the business wants to have both Vendor & material information in the same repository then we need to have multiple main table to give the link. If there is no link & the data is only used for reporting, it can be entered in a seperate repository.

Regards,

Pramod

[Former Member · Accepted solution]

Hi Beth,

If you are using MDM 5.5, we can have any number of seperate Repsoitories (Main table) & lookup tables associated with it. If using MDM 7.1, can use related Main tables in one Repsoitory & lookup tables associated with it.

In your case do not have Main tables related with each other, but if you have reference data (look up) tables related to all these Main tables, then can use 1 Repository with all different Main tables & with same reference data associated with all these Main tables data.

Had used 7 main tables in single repository (Maximum) in my previous project.

Regards,

MSR

[Former Member · Accepted solution]

One of my repositories is up to 7 Main tables (yes - all related subject areas). Each is chunky, between 30K and 200K rows.

Would've loved to use Tuples - if only there was a way to enforce uniqueness.

No ill effects that I can see...in general stability, Win32 UIs or API. (we're on HP-UX 11.31 w/ Oracle 10G).

Server side memory usage is up (as expected), but client side memory usage is much lower than I'd expected. Other repositories that contain more lookup tables use more desktop memory.

...Dee

[Former Member]

I am not hearing an official limit - but it is obvious that others have done this up to at least 7 tables without too many problems!

Our tables are not very large - longest has 30K entries - but most are under 1000 lines.

Thanks!

[Former Member]

Hi Beth,

As far as i know you can have many main tables.

Points that should be considered:

1. Is that a specific requirement to have 2 main tables in the same repository (there might be scenarios where a company maintains 2 masters one is a stabdard & other is customised based on the needs but both have same primary identifier).

2. As Michel mentioned downtime is also a concern if you bring many main tables in a single repository.

3. As th enumber of records will be more there will be performance related issues.

Regards,

Pramod

[michael_theis]

Hi Beth,

I'm not aware of any restriction by MDM. Nevertheless you should always consider the impacts of your data model.

MDM is a in memory tool, which means that all records of all main tables are loaded into the Server's memory. The more main tables you create, the more records you will obviously have in your repository and the more harware memory you'll need.

A second thought you should spend some time on is: do I need multiple main tables in my repository? In general, a main table should be used for an object that can live on its own, e.g. like a Vendor or Material. If an object needs another object to provide valuable information, it shouldn't be in a main table. An example is an address: although you might consider an address as a object, the address always needs a Vendor main object - otherwise you'd have only some street and city information without any valueable content. Next question is: do my objects relate with each other? Surely you could put Vendors and Materials into a single repository. But if you do not use any lookup from the Material to the Vendor object (or vice versa), you could use two repositories as well.

Additionally you should consider the downtime of a repository. What happens if your repository is unloaded? How many users and business cases will be affected? How long does it take to load a huge repository compared to several smaller ones?

Best regards

Michael