Subreports - slow

rbuser

I have a report with 10 subreports...I think thats the reason why my report
runs slow. Is it possible to make things run any faster? The queries behind
each of the sub reports are fairy simple, they take on average about 2 secs
to run, although my reports takes arounds 45 seconds. Its a normal
Master/Detail report with no fanct formatting either...any ideas?

Cheers
Shanil.

nardmoseley

There are two approaches to linking queries - see the article below. The
second approach, RB DataPipeline linking will result in faster performance -
try that.

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Tech Tip: Linking SQL Queries for Master/Detail Data
------------------------------------------------------

The following example shows two options for linking SQL queries to create a
master/detail relationship.

In this example, we are using Delphi's DBDemos data to create a
Customer/Order relationship. Thus we wish to link the Orders detail to the
Customer master.

I. Delphi Query Linking
------------------------

a. Set the detail TQuery.DataSource property to point to the master
query's TDataSource component.

b. In the SQL "Where" clause for the detail query use a ':' followed by
the linking field name from the master:

example
select *
from orders
where orders.CustNo = :CustNo

Now each time the master record position changes, the detail query will
automatically be refreshed with the correct result set.


II. RB DataPipeline Linking
-----------------------------

a. Set the detail DataPipeline.MasterDataPipeline to point to the master
DataPipeline.

b. Use the detail DataPipeline.MasterFieldLinks property to define the
linking relationship

c. In the SQL for the detail, retrieve all records and sort them by the
linking master field:

select *
from Orders
order by CustNo


Notes:

1. Using RB DataPipeline, each query is executed only a single time - thus
performance is much faster.

2. RB Professional and Enterprise Editions include a visual Data environment
for creating SQL queries, defining linking relationships, and creating
Ask-At-Runtime parameters. Using the RB tools you could create the above
linked queries in about 10 seconds.


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Nard Moseley
Digital Metaphors
http://www.digital-metaphors.com