Cardinality Problem

building semantic layer
1

Hai,
I manually created a simple join between two tables in the universe and did detect cardinality. I get this message as unknown cardinality. Why do I get that message.

Thank You.
Radhika

Listserv Archives (BOB member since 2002-06-25)

2

I’ve had similar problems and BO actually tries to modify my cardinalities when I detect them. Tech Support told me that ‘detect cardinality’ is unreliable. Just follow your data model and don’t even do the detection.

Hai,
I manually created a simple join between two tables in the universe and did detect cardinality. I get this message as unknown cardinality. Why do I get that message.

Thank You.
Radhika

Listserv Archives (BOB member since 2002-06-25)

3

Radhika wrote…
I manually created a simple join between two tables in the universe and did detect cardinality. I get this message as unknown cardinality.
Why do I get that message.

Business Objects detects cardinality based on the columns joining the tables and the actual data in the tables. I’ll explain in an example, it may make more sense.
If you have two tables with a 1:M relationship, such as CUSTOMERS and ORDERS, however there just so happens to be one customer record and one order record for that customer. BO will detect a 1:1 relationship but the relationship really is 1:M. So what you need to do is override BO’s automatic detection of the cardinality.
This is how you do that:

  1. Go to Join Properties for the join in question 2) Manually specify the cardinality between the two tables 3) Uncheck the box that says Detect Cardinality. This will ensure that BO will not detect the cardinality for that join.
    That’s it!

Listserv Archives (BOB member since 2002-06-25)

4

It could be that the columns that you have connected these 2 tables by are incorrect. When you detect cardinality, BO reads some rows from the table and tries to figure out the cardinality. If the columns are incorrect, then you get ‘Unknown Cardinality’ message.

Javed Maqsood
Context Integration

Radhika Mandava wrote:

Hai,
I manually created a simple join between two tables in the universe and did detect cardinality. I get this message as unknown cardinality. Why do I get that message.

Thank You.
Radhika

Listserv Archives (BOB member since 2002-06-25)