Operation Manual

Understanding Databases
Linking tables
25
492 Crystal Reports User’s Guide
Extended descriptions of chart columns
The performance charts use the following columns:
• Linking or Subreport
Are you creating a report from linked databases or are you inserting a
subreport and binding it to the data in your primary report?
• Selection Formula
Does your primary report include a record selection formula that sets
range limits on the key (indexed) field in Table A?
• Index A
Is Table A on the field you are going to use indexed to match up the records?
• Index B
Is Table B on the field you are going to use indexed to match up the records?
• Reads A
How many records does the program have to read out of Table A to find
the two records it is looking for?
• For each A reads in B
How many records does the program have to read in Table B to find the
200 records it is looking for?
• Total Records Read
What is the total number of records the program has to process to
complete the task?
PC Data
Linking/
Subreport
Selection
Formula
Index A Index B Reads A For each A
reads in B
Total Records
Read
Linking No Yes or No Yes 26 100
(26*100)
2600
Linking Yes No Yes 26 100
(26*100)
2600
Linking Yes Yes Yes 2 100 (2*100) 200
Subreport No No No 26 2600
(26*2600)
67,600
Subreport No Yes No 2 2600
(26*2600)
67,600
Subreport No Yes Yes 26 100
(26*100)
2600