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I have a database in which there are companies, sites, and accounts servicing the sites. Most of the time there is one account per site but it may be the case that one account covers many sites. There is a sites table and an accounts table. Is there a way to join these guys without the use of an intermediate table holding id's from each table?
Sorry if this is obvious but I am used to financial modeling not database development.
Mark
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mjackson11 wrote:
Is there a way to join these guys without the use of an intermediate table holding id's from each table?
No, you must use an intermediate table if you want to keep the data model normalised. Even in database systems that permit Many-to-Many joins directly it is implemented with an intermediate table under the covers.
If you are willing to denormalise the datamodel you could implement it without the intermediate table if there were a limited number of possibles joins, say an Account can cover a maximum of 3 sites. You have three site foreign key references on Account that are nullable (just in case there are not exactly 3 sites) and vice versa. This will, however, become much more difficult to maintain than the intermediate table solution.
Is there any particular reason why you don't want to use an intermediate table?
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>Is there any particular reason why you don't want to use an intermediate table?
I'm lazy  . No reason really, it will just take a couple days to add the table and make sure the data is converted, then audited.
We have sites/account combinations that would require 15 links so I will put in a sites-account table.
Thx for the info. I found your blog article very helpful.
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We are developing a VB.NET database application, using windows forms and Microsoft Access.
The application requires dynamic reports, where the users change data on the forms, if a report is being shown it will automatically update.
To do this we are using the .NET crystal report viewer, which loads a crystal report that we set it's data source at runtime using a dataset. If the user changes data on the data collection form, we update the dataset and refresh the reports data source.
The problem we are getting it's with the memory overhead. When we first show the form containing the crystal viewer control, an additional 20Mb of memory is allocated. Every time the report is then refreshed with the updated dataset, 1-2Mb is added to the memory each time. If we close the report viewer form, none of the memory is ever recovered. If the report is displayed again, the memory keeps increasing with every refresh.
Is there a way to release the memory used by the crystal viewer, or is this a know issue. If it is an issue does anyone have any better alternative to crystal reports?
Any advise would be appreciated.
Jason
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I am getting the same problem, any suggestions would be very much appreciated.
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We had a similar problem a while ago with crystal 8.5. From the research we did we found the following (to the best of my understanding). It seems when you open the report it loads all the data into an array in memory. You initially get a very large increase in the resources used (about a meg for the viewer object and other objects if you use charts etc and the rest for the data for the first report, This in your case is about 18 meg). When you close the form the viewer object is destroyed but the array is not(you should see a small drop in allocated memory). The next time you run a report it again creates the viewer object adding a few more meg. The data is loaded into the already existing array. If the data is more than before the array will grow. If it is less it all fits into the existing array and NO changes are made to the size. The array is destroyed when you close your application.
As our application was running on a terminal server we found out about the problem very quickly (clients server died if several people ran reports). With crystal the problem is made all the worst by the fact it will load ALL the data into the array then work on any critera you have set, so it may load 3 linked tables in their entirety yet only display 2% of the records if that all that fits the selection criterea.
Rather than upgrade and risk running into the same issues we just switched to Active Reports by DataDynamics which are XML layout based and have a tiny memory footprint.
So, sorry to say but i think if you want to use crystal you are stuck with this.
Jon
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Thanks for your reply. I am not tied into sticking with crystal reports, but after looking on DataDynamics website, it would cost us $10k for a site license of active reports.
DO you know of any cheaper alternatives?
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Sorry but no. There are only 2 of us developing here and one of the things we really wanted to do was give the end users the ability to alter the reports. The crystal report designer component licence is more restrictive and would result in us having to substantially increase to cost of our software. The DataDynamics one is royalty free so for us it was actually a far cheaper option than crystal anyway.
Jon
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 hello i am a beginer. i want to program on a PDA to identify chinese medicine. i need to setup a database to store all the info about chinese medicine. how to store both text and pictures inside and can i use chinese characters?
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tudou wrote:
can i use chinese characters
I would have thought so.
tudou wrote:
how to store both text and pictures inside
If you don't know how to store text, then you need to buy a basic book on databases, or read the help that came with your database.
Christian Graus - Microsoft MVP - C++
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Hello,
I'm programming an application for a multi user environment, so multiple users will work with different applications on the same database tables.
Now, here's my problem.
Lets say user A en user B start the application, and there local dataset is filled. Let's say user A changes row 1, automatically the application will save this in the application and in the database. But now user B doesn't have this latest info yet.
How do i solve this?
Nowadays it's working like this, each minute the application is getting the latest info from the database, and the datagrid is redrawn with the new latest info.
but i would like to compare the current dataset for changes with the new dataset from the database. Is there an easy way to do this?
thx
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There's nothing you can do about what is shown on one clients screen while another is changing it, unless you lock records so only one person can have them at a time. I'd lock only when you get to a point of editing, and then users will find out someone beat them to it if they try to edit something that someone else has grabbed. The 1 minute refresh is basically a race condition, and a drain on your database server resources.
Christian Graus - Microsoft MVP - C++
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I have created one site and want to upload it .but i do not now how to restore the database to the server.if i can do this only by using enteprize manager .if yes i do not now how to enter the server!for example i can copy the web pages of the site in the www.root ,i can copy the database to the wwwroot too.but can not restore it.The problem is i do not now how to access to the programs(such as enteprize manager)in the server?
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Anonymous wrote:
i can copy the database to the wwwroot too.but can not restore it
I answered a very similar question a few hours ago. You can find it on this forum here[^]
Anonymous wrote:
The problem is i do not now how to access to the programs(such as enteprize manager)in the server?
If you need to access programs in general on the server then you can use Remote Desktop Connection (assuming the administrator of the server permits in-bound connections and your account has permission to be accessed remotely in this way), it is in your Start --> All Programs --> Accessories --> Communications menu.
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I am trying to create a deployment project for my windows app using the MSDE deployment toolkit so my database and SQL will be automatically configured on client machines. The only information i have to work with is an article at http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnmsde/html/msdedepl.asp[^]
I was wondering if anyone could help me out with the code and or sql statements for actually creating the database, tables, login info, etc. I dont know that much about SQL or SQL statements. I have written a complete app using a SQL database and it works great i just need help with my deployment using the MSDE toolkit because that looks like the best way to go for ease of installation. If anyone has any input, code, just any kind of help with this, i would greatly appreciate it. Thank you.
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Can I create a table for a *.mdb file with a sql statement (crate table{}) in asp.Thanks for your help from now
enigma
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i've developed an application that uses ADO.NET.
If want to distribuite it do i need to save in the user installation diretory some dll or other files?
Thanks
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how is it possible to distribuite an application about 500 kb to force the final user to install all the .NET framework.
It is a very bad nonsense!!!!
Is there someone more serious can answer?
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Sasuko wrote:
how is it possible to distribuite an application about 500 kb to force the final user to install all the .NET framework.
Easy, if they don't install the .NET framework the application doesn't work. So if they want it to work they must download the .NET Framework.
Sasuko wrote:
It is a very bad nonsense!!!!
23Mb these days is not a lot for a download. Most JVMs are of a similar size.
Sasuko wrote:
Is there someone more serious can answer?
My answer was was serious. I suggest you just didn't like it and don't want to accept it.
Remember that the .NET Framework only has to be installed once for all .NET applications on the machine so if they already have it then they don't need to download it again.
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as colin replied, there is no nonsense in installing the framework if your program was coded in a .NET language.
do you only know what you do when you compile and when you execute a .NET language ?
if you didn't want so much task to do for your customer, you had to do it in MFC or Win32 or VB6 for example...
TOXCCT >>> GEII power
[toxcct][VisualCalc]
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so the user need to install the framework .NET also if he has windows XP or just for the others older WINDOWS 32 OS?
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no, of course he does need to install something that is already installed...
in fact, you will have to test into your installer if the framework already exist, and if not, propose to install it...
TOXCCT >>> GEII power
[toxcct][VisualCalc]
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so Windows XP user have got by default .NET on their pc?
How can i test in my installer?
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Sasuko wrote:
so Windows XP user have got by default .NET on their pc?
No, Currently only Windows Sever 2003 ships with the .NET Framework.
Sasuko wrote:
How can i test in my installer?
If I remember correctly, if you built your installer using a setup project in Visual Studio then it tests for you because it is set with the details of the components required.
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