Thursday, May 22, 2008

What is a Chasm Trap

Posted by sapbotopics

What is a Chasm Trap

Simply put: A chasm occurs when a series of joins crosses a many >- one -<>

A >- B -<>

If I were to write a query that spanned all three of those tables the data from table A and C would be duplicated and measure values would be inflated. The inflation factor can be determined by counting the number of rows from the left that match a particular key and multiplying by the number of rows on the right....... for more details

Read more »

What is a Chasm Trap

Posted by sapbotopics

What is a Chasm Trap

Simply put: A chasm occurs when a series of joins crosses a many >- one -<>

A >- B -<>

If I were to write a query that spanned all three of those tables the data from table A and C would be duplicated and measure values would be inflated. The inflation factor can be determined by counting the number of rows from the left that match a particular key and multiplying by the number of rows on the right....... for more details

Read more »

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