Solved

Two TZQuery'ies connected via MasterSource

Posted on 2012-03-21
9
1,024 Views
Last Modified: 2012-03-21
Hello Experts!

I have to TZQuery components.

They are providing data from two Master- Detail tables.

It looks like this:

1.

select * from table1 where index = 1;

2.

select * from table2;

These two TZQuery are connected together via MasterSource, MasterFields, LinkedFields and IndexFieldNames.

It works fine but slowly.

I wonder if I could make it work faster...?

Maybe I should avoid queries like:

select * from table2?

What is the best practice to realize this master- detail connection?

Thank you

panJames
0
Comment
Question by:panJames
  • 7
  • 2
9 Comments
 
LVL 36

Expert Comment

by:Geert Gruwez
ID: 37746930
to provide tuning solution, you'll need to indicate what database you are using
in general:
minimize your column list (only select columns you really want)
minimize your rows returned (do you actually read more than 25 lines ?)

for master-detail you can usually combine in 1 query

select
  m.column1 master_col1,
  m.column2 master_col2,
  m.column3 master_col3,
  d.column1 detail_col1,
  d.column2 detail_col2
from table1 m
  left join table2 d on m.mastercolumn = d.mastercolumn
where m.index = 1;

displaying the data in the detail view can be done by applying a filter on the data in memory
0
 
LVL 36

Expert Comment

by:Geert Gruwez
ID: 37746938
when tuning a problem the basics should be checked too:
network > amount of data to copy
local pc > cpu load, memory,
database type > local, server, load
query > optimal execution path ?
0
 
LVL 36

Expert Comment

by:Geert Gruwez
ID: 37746941
delphi is all about code
if you don't supply code, it's mainly guessing where your problem is
0
 

Author Comment

by:panJames
ID: 37746999
"minimize your rows returned (do you actually read more than 25 lines ?)"

how do you make your query return only lets say maximum 25 lines?

Thank you

panJames
0
Highfive + Dolby Voice = No More Audio Complaints!

Poor audio quality is one of the top reasons people don’t use video conferencing. Get the crispest, clearest audio powered by Dolby Voice in every meeting. Highfive and Dolby Voice deliver the best video conferencing and audio experience for every meeting and every room.

 
LVL 36

Expert Comment

by:Geert Gruwez
ID: 37747003
database type ?
0
 
LVL 36

Expert Comment

by:Geert Gruwez
ID: 37747027
mysql
select columns from table LIMIT 1, 25

oracle
select columns from table where rownum <= 25
> doesn't have a offset

in the properties of some query components you can find this:
FethAll: boolean; (default false)
FetchCount: 25; (default)

some grids like devexpress know this and can call FetchNext to get all data
0
 
LVL 36

Expert Comment

by:Geert Gruwez
ID: 37747072
Zeos lib components don't have this functionality
you'll have to use other components or do it with sql
0
 

Author Comment

by:panJames
ID: 37747079
Firebird
0
 
LVL 36

Accepted Solution

by:
Geert Gruwez earned 500 total points
ID: 37747115
0

Featured Post

How to run any project with ease

Manage projects of all sizes how you want. Great for personal to-do lists, project milestones, team priorities and launch plans.
- Combine task lists, docs, spreadsheets, and chat in one
- View and edit from mobile/offline
- Cut down on emails

Join & Write a Comment

Entering time in Microsoft Access can be difficult. An input mask often bothers users more than helping them and won't catch all typing errors. This article shows how to create a textbox for 24-hour time input with full validation politely catching …
Shadow IT is coming out of the shadows as more businesses are choosing cloud-based applications. It is now a multi-cloud world for most organizations. Simultaneously, most businesses have yet to consolidate with one cloud provider or define an offic…
Video by: Steve
Using examples as well as descriptions, step through each of the common simple join types, explaining differences in syntax, differences in expected outputs and showing how the queries run along with the actual outputs based upon a simple set of dem…
Polish reports in Access so they look terrific. Take yourself to another level. Equations, Back Color, Alternate Back Color. Write easy VBA Code. Tighten space to use less pages. Launch report from a menu, considering criteria only when it is filled…

706 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

19 Experts available now in Live!

Get 1:1 Help Now