BusinessObjects Board

Linking Universe

building semantic layer
#1

Hi Gurus :slight_smile: ,
I had a new requirement, where i am having three different database , there i have to generate reports using that three database.can i generating three seperate universe on connecting to that three database or is it possible to generate a single universe on linking the three universe else can i link the three universe on the report level so that i can generate the report .wht is the possible way of doing this.looking for your suggestions

Rajasekar :india: (BOB member since 2004-07-16)

#2

If you are really talking of 3 different databases(and not 3 instances of a database), then it is not possible with a single Universe. It is possible doing at the report level.

Create three different Universes pointing to these databases.
Create 3 dataproviders in your report using these Universes and link them at the report level appropriately.

While doing this it is advisable to have minimum calculations at the report to acheive good performance.

Hope this helps…

Ashokkumar (BOB member since 2004-05-20)

#3

Hi Ashok,
Thanks for your help.Actually i am doing the report as u said .i

had another doubt on linking the universe.Whether we can link the

universe with the same connection or can i link the three universe with

different connection(I am confused with this concept).Looking for your

reply.

Rajasekar :india: (BOB member since 2004-07-16)

#4

You might want to experiment a bit with this before you decide that this is the solution.

The report level joins sounds like a good idea, but unless your databases are very much in sync on the dimensions you want to link it is not.

IÂ’ve tried this linking only two universes and had problems like:

  • The behavior of functions like runningsum() etc. becomes unpredictable if you have blanks for one of the dimensions
  • It is difficult (some times impossible) to create inner joins
  • WeÂ’ve had big problems when we updated one of the universes. Usually BusinessObjects crashes with and unhandled exception when you refresh the data in it. So far weÂ’ve been able to workaround the problem by manually opening all data providers (updating the SQL) before we refreshed the report.

So my conclusion is that this feature can only be used in an ad-hoc situation for a single report. As a general solution you have to merge the data at database level.

Tom Bjerre (BOB member since 2003-09-15)

#5

Hi Tom,
Thanks ya i got the solutions finally from your reply.can u tell me , it is advisible to link the universe.How many universe can be linked in one time.Then if i have to link the universe whether it should be in secured connection or shared one.

Rajasekar :india: (BOB member since 2004-07-16)

#6

A universe uses one and only one connection. If you link universeB (using connectionB) into universe A, it will use the connectionA only. Stated another way, only the definitions (tables, joins, objects) of the “source” universe are used. The connection is ignored.

Dwayne Hoffpauir :us: (BOB member since 2002-09-19)

#7

Hi Dwayne ,
Thanks for the reply.Actually I need to know one thing, when we are linking the universe whether it should be in secured connection or shared connection.

Rajasekar :india: (BOB member since 2004-07-16)

#8

Secured Connection… Reason for linking your Kernel Universe should be exported atleast once to the repository… Now if you want to Export any Universe to the Repository then the Universe Connection should be Secured… Hope you get the info…

Sridharan :india: (BOB member since 2002-11-08)

#9

Hi Sri,
I am using bo6.1,I created two universe one is with oracle and the other one is with sql server.i exported the two universe to the universe domain.Then i tried to link the two universe but it throwing link error saying that “This universe has not been exported yet please export it and import it”, but i exported that universe previously.I am very much confused with this concept.if i link two universe it should have secured connection and it should be in single connection(oracle or sql).Kindly let me know the suggestions.

Rajasekar :india: (BOB member since 2004-07-16)

#10

Yes the connection has to be Secured and you are trying to connect Oracle and SQL Server… It doesn’t work that way… A Linked Universe uses only one connection that of the Parent Universe which can be either Oracle or SQL Server… So in your case Objects belonging to the other DB are bound to fail…

Also check this thread

Sridharan :india: (BOB member since 2002-11-08)

#11

Hi,
I created a new universe using the sql database and already has a universe developed by connecting to sql.Now i tried to make a link bet’n this two universe , eventhough it is giving me the same error

.looking for the suggestions.

Rajasekar :india: (BOB member since 2004-07-16)

#12

Presuming it is Oracle you’re talking about, we also user database links to link to databases into one single universe if you need small amounts of data from another database. I don’t know if your databases are far apart but if they are close it could be a good option.
To be able to use database links some work has to be done :roll_eyes: :

  • the DBA has to create the actual database link;
  • you have to edit your STORA7EN.TXT file and add a new strategy;
  • in Designer set your Strategies (File-Parameters) for Tables to your new strategy;
  • add the table(s) you need from the external database and set the strategies to “Built-in”.

Disadvantage is that if you use explain plans you can’t see what is happening over the database link (black box), only what is in your own database.

HenkK

HenkK :netherlands: (BOB member since 2004-03-02)

#13

I am using sql database.

Rajasekar :india: (BOB member since 2004-07-16)

#14

Linked universes cannot combine two different databases. Only one SQL program will be written by BusinessObjects for any query from the universe, and one SQL program cannot span Oracle + SQL Server at the same time. So your project is not going to work.

In any case, the process of linking goes like this:

  1. Build Universe A
  2. Export Universe A
  3. Build Universe B
  4. From within Universe B, click the Link option
  5. Browse your hard drive, and find the copy of Universe A that has been exported, and select it. Note that all linked universe must exist in the same repository, it’s not enough just to have exported it. It has to be in the same repository that you logged in to.

Note that universe “A” does not have to be exported prior to linking, only universe “B”. Also, if you have multiple copies of “B”, you must select the one that has been exported. If you find Universe “B” in the standard universe folder, it has not been exported. You have to go into the folder named after the domain that contains the linked universe.

Dave Rathbun :us: (BOB member since 2002-06-06)

#15

Hi Gurus,
Thanks a lot for all of your replies, finally i achieved. :smiley:

Rajasekar :india: (BOB member since 2004-07-16)