Interested to Buy Any Domain ? << Click Here >> for more details...
Aliases and Contexts Which once will give the better
performence when resolve the loops?
- 3 Answers
- 8710 Views
- HCL, I also Faced
- E-Mail Answers
Answer Posted / narender reddy
Join path: a join path is a series of joins that a query can use to access data in the tables linked by the joints. Join path problems can arise from the limited way that lookup and fact tables are related in a relational data base. The three major join problems that you encounter when designing a schematic are the following:
1. Loops
2. Chasm traps
3. Fan traps
Queries can return incorrect results due to the limitations in tha way that joins are performed in relational databases.
Loops: joins between tables form a continues path
Solved by: shortcut join(3 tables), aliases( more than 3 tables with one fact table), context( more than 3tables with more than one fact table),
Chasm traps: many to one joins from two fact tables converge on a single lookup table. This type of join convergence can lead to a join path problem called as a chasm trap.
Solved by: context, creating multiple SQL statements for each measure, creating multiple universes( webi only),
Fan traps: a one to many join links a table which is in turn linked by a one to many join. This type of serial many to one joins can lead to a join path problem called a fan trap.
Solved by: alias, using multiple SQL statements for each measure, creating the context using the alias.
Aliases: An alias is a table that is a exact duplicate of the original table, with a different name. The data in the table is exactly the same as the original table. Using aliases resolve loops and fan traps.
Context: context is a collection of joins which provide a valid query path for user to generate SQL. Using contexts we can resolve loops and chasm traps and assisting in some solutions of fan traps.
-------- when we use alias to resolve the loop we are using extra duplicate table, if we have more tables in schema it will decrease the performance so alias always decrease the performance compair to context.
| Is This Answer Correct ? | 4 Yes | 0 No |
Post New Answer View All Answers
How can we do load testing for webi reports? (Example if I have have to test one webi report for concurrent users refreshing report at one time)?
What are the steps to do to use alerts in bo?
Did you face any problems while creating reports? Name? Solutions?
IN THE REPORT I WANNA APPLY HYPERLINK FOR A CELL IN THE COLUMN/ROW HOW TO ACHIEVE THIS? EG: YEAR COLUMN : 2001,2002,2003,2004 I WANNA APPLY FOR 2001 ONLY
What is the difference between business requirement document and use case document.
What are all difference between business objects 6.5 and xi r2?
Can we Save (save as) WEBI Doc as DESKI?
Explain when we use aggregate awareness function in designer?
Explain in detail about type 2(scd),
Are data mart and dwh normalized or denormalized? Do both of them exist in the same tier?
How we drill up week to month?
Is there any tool that can compare two unvs / two rpts , built using bo 5.1 / bo 6.5?
Hi I'm using data federator.I would like to know if it allows select statment in where clause.For example: SELECT Employee, company, orgunit FROM TAB_BIG WHERE employee IN (Select TAB_SMALL.employee FROM TAB_SMALL WHERE flag = X ) bye
1)I have createcd a dashboard on Bex query. How to refresh the Dashboard without hitting the bex query? 2)What is Event based scheduling in BO? 3) How to display the BO webi report title using a function? 4) For eg in my webi report iam having a person name like Jhon Peter Adam. But i need to get only the middle name of the person like Peter. What function is used in Webi to get this?
Hi friends,
I am trying to create OLAP connection in IDT. I am getting
error "error code:405 METHOD NOT ALLOWED"
I am using "http:
