BorlandTalk.com Borland discussion newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  ClientDatasets question (general db question)          BorlandTalk.com Forum Index -> Delphi Databases (Multi-Tier) View previous topic :: View next topic   Author Message Pete Wason Guest Posted: Thu Jul 15, 2004 12:28 pm    Post subject: ClientDatasets question (general db question) Hiall! I'm writing a small app for a client which among other things has three datasets artists, recordings and reviews. Recordings and reviews have an integer ArtistID field, and reviews has an integer RecordingID field. I'm using dbcombolookup controls to show/pick data for Artist and Recording. The client wants to be able to sort recordings by Issue (an integer field in reviews) and by Artist, or just by Artist. I'm trying to figure out how to do this. Any help will be greatly appreciated. TIA! Pete [email]codevark (AT) netscape (DOT) net[/email] Back to top Bill Todd (TeamB) Guest Posted: Thu Jul 15, 2004 1:18 pm    Post subject: Re: ClientDatasets question (general db question) Use a SELECT statement that joins the three tables and orders by Issue. -- Bill (TeamB) (TeamB cannot respond to questions received via email) Back to top Pete Wason Guest Posted: Fri Jul 16, 2004 11:46 am    Post subject: Re: ClientDatasets question (general db question) Bill Todd (TeamB) wrote: Quote: Use a SELECT statement that joins the three tables and orders by Issue. well, list that would be great except that TClientDatasets don't deal with SQL, unless the various texts I'm reading are misleading me. If I can in fact use SQL statements with these datasets, the path is clear. Otherwise I might have to add another dataset or something... Pete Back to top Bill Todd (TeamB) Guest Posted: Fri Jul 16, 2004 2:00 pm    Post subject: Re: ClientDatasets question (general db question) The word "TClientDataSet" does not appear anywhere in your original message. What else are you not telling us about what your are trying to do? :) You cannot sort a CDS on a field that is not part of the CDS. You might be able to use and internal calculated field to get the value to sort by. -- Bill (TeamB) (TeamB cannot respond to questions received via email) Back to top Ed Guest Posted: Fri Jul 16, 2004 2:28 pm    Post subject: Re: ClientDatasets question (general db question) Bill Todd (TeamB) wrote: Quote: The word "TClientDataSet" does not appear anywhere in your original message. and what about the title ?? Back to top Pete Wason Guest Posted: Mon Jul 19, 2004 2:14 am    Post subject: Re: ClientDatasets question (general db question) Bill Todd (TeamB) wrote: Quote: The word "TClientDataSet" does not appear anywhere in your original message. What else are you not telling us about what your are trying to do? :) You cannot sort a CDS on a field that is not part of the CDS. You might be able to use and internal calculated field to get the value to sort by. Sorry, I thought the subject of "ClientDataset question" would have been enough to identify the type of component I'm using. Excuse my brevity. I've reread the D5 Developer's Guide regarding ClientDatasets, but am not seeing clearly how to do this thing. I thought about having a "filter by issue number" dropdown that would be populated with unique issue numbers from reviews, but even with that, what would my next step be? Would my problem be less thorny if there were a clear master-detail relationship here? Apparently, according to the client, no recording will ever appear in multiple issues or reviews, but I hesitate to design data relationships on this assumption. The tables look something like this: Artists ID Name etc. Recordings ID Name ArtistID Image1File Image2File Image3File Reviews ID Title RecordingID ArtistID Issue etc. Obviously, Artists <--> Recordings is a one-to-many relationship. Reviews <--> Artist+Recording is a one-to-one relationship (apparently). I suppose I could 1. use the dropdown described above 2. filter Reviews for the chosen issue number 3. iterate over Reviews and build a (possibly lengthy) filter expression made up of all the RecordingIDs 4. apply this new filter to the Recordings dataset to show only Recordings reviewed in the chosen issue. or maybe it's just too late, and there's a much simpler way of doing this that I'm not seeing right now... yawn. tfrm. Pete Back to top Bill Todd (TeamB) Guest Posted: Mon Jul 19, 2004 5:52 pm    Post subject: Re: ClientDatasets question (general db question) Quote: Sorry, I thought the subject of "ClientDataset question" would have been enough to identify the type of component I'm using. Excuse my brevity. You are right. I certainly should have seen that. Quote: I've reread the D5 Developer's Guide regarding ClientDatasets, but am not It is always a good idea to include the version of Delphi and any other software in your message when you are not using the current version. If you don't give the version everyone will assume D7 and that could lead to an inappropriate answer. Quote: seeing clearly how to do this thing. I thought about having a "filter by issue number" dropdown that would be populated with unique issue numbers from reviews, but even with that, what would my next step be? Would my problem be The two obvious ways are to use a join in your SELECT statement that includes the issue number in the result set. That way you can sort on it just as you do with other fields in the CDS. If you do this you will need to set the pfInUpdate provider flag for the issue number field object to false and write an OnGetTableName event handler for the DSP to return the name of the table to update. The only other method that occurs to me is to use an internal calculated field to get the issue number, however, I would use the join. -- Bill (TeamB) (TeamB cannot respond to questions received via email) Back to top Pete Wason Guest Posted: Mon Jul 19, 2004 7:17 pm    Post subject: Re: ClientDatasets question (general db question) Bill Todd (TeamB) wrote: Quote: Sorry, I thought the subject of "ClientDataset question" would have been enough to identify the type of component I'm using. Excuse my brevity. You are right. I certainly should have seen that. I've reread the D5 Developer's Guide regarding ClientDatasets, but am not It is always a good idea to include the version of Delphi and any other software in your message when you are not using the current version. If you don't give the version everyone will assume D7 and that could lead to an inappropriate answer. seeing clearly how to do this thing. I thought about having a "filter by issue number" dropdown that would be populated with unique issue numbers from reviews, but even with that, what would my next step be? Would my problem be The two obvious ways are to use a join in your SELECT statement that includes the issue number in the result set. That way you can sort on it just as you do with other fields in the CDS. If you do this you will need to set the pfInUpdate provider flag for the issue number field object to false and write an OnGetTableName event handler for the DSP to return the name of the table to update. The only other method that occurs to me is to use an internal calculated field to get the issue number, however, I would use the join. umm... so I *can* use SQL with CDS? I was under the impression I had to do everything with filters, ranges and the like. If I can use SQL, then the join idea is obviously easy (and easily obvious). I'm not sure where I read that I couldn't use SQL, but it stuck in my head for some reason. And I'm using D6, BTW; I just have the D5 book to work with as most of my previous work was in D5. Thanks! Pete Back to top Bill Todd (TeamB) Guest Posted: Mon Jul 19, 2004 7:36 pm    Post subject: Re: ClientDatasets question (general db question) On Mon, 19 Jul 2004 15:17:27 -0400, Pete Wason <Codevark (AT) netscape (DOT) net> wrote: Quote: umm... so I *can* use SQL with CDS? I was under the impression I had to do everything with filters, ranges and the like. If I can use SQL, then the join idea is obviously easy (and easily obvious). I'm not sure where I read that I couldn't use SQL, but it stuck in my head for some reason. And I'm using D6, BTW; I just have the D5 book to work with as most of my previous work was in D5. Sorry. I forgot that you are using the CDS as the database and are not connected to a database through a DSP. The only way I can think of to do what you want in that environment is to use an internal calculated field to get the issue number from the other CDS and sort on the internal calculated field. I have never tried that but it should work. -- Bill (TeamB) (TeamB cannot respond to questions received via email) Back to top Pete Wason Guest Posted: Tue Jul 20, 2004 9:36 pm    Post subject: Re: ClientDatasets question (general db question) Bill Todd (TeamB) wrote: Quote: On Mon, 19 Jul 2004 15:17:27 -0400, Pete Wason wrote: umm... so I *can* use SQL with CDS? I was under the impression I had to do everything with filters, ranges and the like. If I can use SQL, then the join idea is obviously easy (and easily obvious). I'm not sure where I read that I couldn't use SQL, but it stuck in my head for some reason. And I'm using D6, BTW; I just have the D5 book to work with as most of my previous work was in D5. Sorry. I forgot that you are using the CDS as the database and are not connected to a database through a DSP. The only way I can think of to do what you want in that environment is to use an internal calculated field to get the issue number from the other CDS and sort on the internal calculated field. I have never tried that but it should work. Thanks! I'll try it and report my findings to the group. ;-) Pete Back to top Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First         BorlandTalk.com Forum Index -> Delphi Databases (Multi-Tier) All times are GMT Page 1 of 1   Jump to: Select a forum C++ Builder Newsgroups----------------C++ BuilderC++ Builder (ActiveX)C++ Builder (Announcements)C++ Builder (Command Line Tools)C++ Builder DatabasesC++ Builder Databases (ADO)C++ Builder Databases (Desktop)C++ Builder Databases (InterBase Express)C++ Builder Databases (Multi-Tier)C++ Builder Databases (SQL Servers)C++ Builder (Graphics)C++ Builder (IDE)C++ Builder (Internet)C++ Builder (Internet Socket)C++ Builder (Internet Web)C++ Builder (Jobs)C++ Builder (Language)C++ Builder (Language C++)C++ Builder (Compatibility with MFC)C++ Builder (Native API)C++ Builder (Non-Technical)C++ Builder (Students)C++ Builder (Third Party Tools)C++ Builder (Upgrade)C++ Builder (VCL)C++ Builder (VCL Components Usage)C++ Builder (VCL Components Development)C++ Builder (VCL Usage)C++ Builder (WinAPI)C++ Builder Installation Delphi Newsgroups----------------Delphi (General)Delphi ActiveX Controls UsageDelphi ActiveX Controls DevelopmentDelphi As400Delphi DatabasesDelphi Databases (ADO)Delphi Databases (dbExpress)Delphi Databases (Desktop)Delphi Databases (InterBase Express)Delphi Databases (Multi-Tier)Delphi Databases (SQL Servers)Delphi DeploymentDelphi GraphicsDelphi IDEDelphi InternationalizationDelphi InternetDelphi Internet Isapi-WebBrokerDelphi Internet WebSnapDelphi Internet WinsockDelphi JobsDelphi Language BASMDelphi Language ObjectPascalDelphi Model Driven Architecture (General)Delphi Model Driven Architecture (Third Party)Delphi MultimediaDelphi Native APIDelphi Non-TechnicalDelphi ObjectPascalDelphi OLE AutomationDelphi OO designDelphi OpenToolsAPIDelphi Reporting-ChartingDelphi RTLDelphi StudentsDelphi TeamSourceDelphi Thirdparty ToolsDelphi Thirdparty Tools (General)Delphi Thirdparty Tools (IntraWeb)Delphi Thirdparty Tools (RaveReports)Delphi UpgradeDelphi VCLDelphi VCL ComponentsDelphi VCL Components UsingDelphi VCL Components WritingDelphi WebServices SOAPDelphi WinAPIDelphi XMLDelphi Installationcomp.lang.pascal.delphi.components.misccomp.lang.pascal.delphi.components.usagecomp.lang.pascal.delphi.components.writingcomp.lang.pascal.delphi.databasescomp.lang.pascal.delphi.misccomp.sources.delphi JBuilder Newsgroups----------------JBuilderJBuilder AnnouncementsJBuilder Applet IssuesJBuilder As400JBuilder CompilerJBuilder CORBA/RMIJBuilder DatabasesJBuilder DB SwingJBuilder DebuggerJBuilder DeploymentJBuilder DocumentationJBuilder EnterpriseJBuilder HandheldJBuilder IDEJBuilder JavaJBuilder JavaAPIJBuilder Java LanguageJBuilder Java SwingJBuilder Java BeansJBuilder Java Beans UsageJBuilder Java Beans DevelopmentJBuilder JBCLJBuilder JDataStoreJBuilder JobsJBuilder LinuxJBuilder MacintoshJBuilder & MobileSetJBuilder MultiLingual AppsJBuilder Non-TechnicalJBuilder OpenToolsJBuilder Servlets (JSP)JBuilder StudentsJBuilder Team DevelopmentJBuilder Thirdparty ToolsJBuilder UpgradeJBuilder Installation InterBase Newsgroups----------------InterBaseInterBase Bug DiscussionInterBase GeneralInterBase IBConsoleInterBase OpenSourceInterBase ReplicationInterBase SQLInterBase ThirdpartyInterBase Installation Miscellaneous Borland Newsgroups----------------AppCenterAppServerEnteraVisiBroker  You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum Powered by phpBB © 2001, 2006 phpBB Group SEO toolkit © 2004-2006 webmedic.