Wat is the difference between rollup and scan?

Showing Answers 1 - 7 of 7 Answers

madhu

  • Aug 17th, 2006
 

by using rollup we cant generate cumulative summary records for that we will be using scan.

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murali

  • Aug 30th, 2006
 

By using rollup we can generate aggregate values like sum ,count?..etc where as by using scan we can generate cumulative summaries of records. In rollup the finalize function is applied to a group of records where as in scan it is applied to every record.

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Faiz

  • Sep 5th, 2006
 

Rollup is used to aggregate data .

Scan is for successive total and is used to  produce summary(cumulative) of data.

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mukund

  • Dec 15th, 2006
 

guys,

Rollup:

 1)generally rollup is used for aggregation purposes such as sum,avg,count,min,max etc.

2)It can process grouped or ungrouped records.while processing ungrouped records it maximises the performance by keeping the intermediate results in main memory

3)It has more control over record selection,grouping and aggregation than aggregate component.

4)it is a multistage component

Scan:

1)scan is used to produce cumulative summary of records such as year-to-date totals for groups of input records

2)it is a multistage component

A multistage component is a componet which transforms the input records in 5 levels,such as input selection,temporary initialization,processing ,output selection,and finalize.for each level it is treated as a transform and a dml is written for each stage.

  hey ,not but the least we can have "SCAN WITH ROLLUP" component to cater the needs of both scan and rollup.

yuppy,

Mukund

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By using rollup we can generate aggregate values like sum ,count…..etc
here no of input records is not equal to output records.
 
where as by using scan we can generate cumulative
summaries of records. In rollup the finalize function is applied to a group of records where as in scan it is applied to every record. here no of input records is equal to output records.

you can use scan as a join also.

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aaa

  • Dec 21st, 2013
 

Could you explain with the help on example

Roll up: Scan:
Aggregate Summary Cumulative Summary
The Finalize function is called at end of each group The Finalize function is called at end of each record
Generates one record for each group Generates record for each record in a group

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