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Datasets - use 1 or many?I'm learning when it comes to Datasets. Should I just have a single dataset
to handle my entire application data or should I use multiple - a dataset for each function or form within my application? Is the data actually written from and queried to the dataset only when needed per a table adapter? It looks like the table adapters .fill method is only invoked when required, so I assume a single dataset would suffice. Is this right? Thanks, Ryan The Fill method is only invoked when you invoke it - so it is up to you to
only do it at the right times. There is no one right answer, but given very few details as to the nature of your app, I would say a safe thing to do is to have 1 for each form. Once a form is closed, you don't want something in your application holding on to that data or still keeping it around. Each form should be able to deal with its own data, and shouldn't need to know about data that belongs to other forms. Show quoteHide quote "Ryan" <Tyveil@newsgroups.nospam> wrote in message news:eTyeUr%23jGHA.1208@TK2MSFTNGP02.phx.gbl... > I'm learning when it comes to Datasets. Should I just have a single > dataset to handle my entire application data or should I use multiple - a > dataset for each function or form within my application? Is the data > actually written from and queried to the dataset only when needed per a > table adapter? It looks like the table adapters .fill method is only > invoked when required, so I assume a single dataset would suffice. Is > this right? > > Thanks, > Ryan > Thanks. This is actually the way I started setting up my project (one
dataset per form). Since each form should need access to at most 4-5 tables and I didn't want to include all 20+ tables in a single dataset. Ryan Show quoteHide quote "Marina Levit [MVP]" <someone@nospam.com> wrote in message news:%23GqGN5%23jGHA.456@TK2MSFTNGP05.phx.gbl... > The Fill method is only invoked when you invoke it - so it is up to you to > only do it at the right times. > > There is no one right answer, but given very few details as to the nature > of your app, I would say a safe thing to do is to have 1 for each form. > Once a form is closed, you don't want something in your application > holding on to that data or still keeping it around. Each form should be > able to deal with its own data, and shouldn't need to know about data that > belongs to other forms. > > "Ryan" <Tyveil@newsgroups.nospam> wrote in message > news:eTyeUr%23jGHA.1208@TK2MSFTNGP02.phx.gbl... >> I'm learning when it comes to Datasets. Should I just have a single >> dataset to handle my entire application data or should I use multiple - a >> dataset for each function or form within my application? Is the data >> actually written from and queried to the dataset only when needed per a >> table adapter? It looks like the table adapters .fill method is only >> invoked when required, so I assume a single dataset would suffice. Is >> this right? >> >> Thanks, >> Ryan >> > > Hi Ryan,
In addition, I suggest you put all relational tables in a DataSet. There is no requirement for using how many DataSets on a form. It's just for your convenience, which makes the developer clear of relations between tables. HTH. Kevin Yu Microsoft Online Community Support ============================================================================ ========================== When responding to posts, please "Reply to Group" via your newsreader so that others may learn and benefit from your issue. ============================================================================ ========================== (This posting is provided "AS IS", with no warranties, and confers no rights.) Kevin and Marina,
I had not seen that you both had answered already while replying. Probably something in my eyes. :-) Others I had written "in addition".So by this. Cor Show quoteHide quote "Kevin Yu [MSFT]" <v-k***@online.microsoft.com> schreef in bericht news:%2335ZNWCkGHA.764@TK2MSFTNGXA01.phx.gbl... > Hi Ryan, > > In addition, I suggest you put all relational tables in a DataSet. There > is > no requirement for using how many DataSets on a form. It's just for your > convenience, which makes the developer clear of relations between tables. > HTH. > > Kevin Yu > Microsoft Online Community Support > > ============================================================================ > ========================== > When responding to posts, please "Reply to Group" via your newsreader so > that others may learn and benefit from your issue. > ============================================================================ > ========================== > > (This posting is provided "AS IS", with no warranties, and confers no > rights.) > Just to give you all an example of one of my forms and an idea of what type
of dataset I need: I have an application form which displays an application sent in by a person (applying for a position on a public board). The form needs to display information from all of the following relational tables: The Person table containing contact information for that person. The Application table containing general information about the application (when and how it was submitted) The Application_mm_Board table which contains a record for each board this application is being submitted for. The Board table which is needed for the name of each board the applicant is applying for. The Application_mm_Question table which contains a record for each question asked on this application The ApplicationQuestion table which stores the questions themselves. The ApplicationAnswer table which stores the applicants answers to each question. The User table which shows who submitted this application if it was input manually by a user. As you can see a even a single dataset for this one form becomes rather large. Do you think I should split it up even further for different functions on the form? Maybe a different dataset for separate datagridviews on the form? Thanks, Ryan Show quoteHide quote "Cor Ligthert [MVP]" <notmyfirstn***@planet.nl> wrote in message news:uvlSaMEkGHA.4040@TK2MSFTNGP05.phx.gbl... > Kevin and Marina, > > I had not seen that you both had answered already while replying. > > Probably something in my eyes. > > :-) > > Others I had written "in addition". > > So by this. > > Cor > > "Kevin Yu [MSFT]" <v-k***@online.microsoft.com> schreef in bericht > news:%2335ZNWCkGHA.764@TK2MSFTNGXA01.phx.gbl... >> Hi Ryan, >> >> In addition, I suggest you put all relational tables in a DataSet. There >> is >> no requirement for using how many DataSets on a form. It's just for your >> convenience, which makes the developer clear of relations between tables. >> HTH. >> >> Kevin Yu >> Microsoft Online Community Support >> >> ============================================================================ >> ========================== >> When responding to posts, please "Reply to Group" via your newsreader so >> that others may learn and benefit from your issue. >> ============================================================================ >> ========================== >> >> (This posting is provided "AS IS", with no warranties, and confers no >> rights.) >> > > Ryan,
I would create datasets containing the main table (have a look at paging so that you can limit them in lenght) and supporting tables. Probably do you in most cases only need the name from the user, so loading that with all its data is a waste of time. I assume that the user table contains probably only the extra data not in the person data. Probably do you need that data nowhere except there where you modify that and to logon, so it can probably only contains forever only one row that you have selected with a where clause (I don't know if you do it already however try to use uniqueindentifiers which are Guids). Probably is a lot related round a user, than try to get only the data from that user with a where clause in your dataset. (In my idea does a datasets not reflect your organisation as a database does. A dataset is for me reflecting the way your data is used) Just my thoughts, Cor Show quoteHide quote "Ryan" <Tyveil@newsgroups.nospam> schreef in bericht news:u0UcI8HkGHA.3484@TK2MSFTNGP03.phx.gbl... > Just to give you all an example of one of my forms and an idea of what > type of dataset I need: > > I have an application form which displays an application sent in by a > person (applying for a position on a public board). The form needs to > display information from all of the following relational tables: > > The Person table containing contact information for that person. > The Application table containing general information about the application > (when and how it was submitted) > The Application_mm_Board table which contains a record for each board this > application is being submitted for. > The Board table which is needed for the name of each board the applicant > is applying for. > The Application_mm_Question table which contains a record for each > question asked on this application > The ApplicationQuestion table which stores the questions themselves. > The ApplicationAnswer table which stores the applicants answers to each > question. > The User table which shows who submitted this application if it was input > manually by a user. > > As you can see a even a single dataset for this one form becomes rather > large. Do you think I should split it up even further for different > functions on the form? Maybe a different dataset for separate > datagridviews on the form? > > Thanks, > Ryan > > "Cor Ligthert [MVP]" <notmyfirstn***@planet.nl> wrote in message > news:uvlSaMEkGHA.4040@TK2MSFTNGP05.phx.gbl... >> Kevin and Marina, >> >> I had not seen that you both had answered already while replying. >> >> Probably something in my eyes. >> >> :-) >> >> Others I had written "in addition". >> >> So by this. >> >> Cor >> >> "Kevin Yu [MSFT]" <v-k***@online.microsoft.com> schreef in bericht >> news:%2335ZNWCkGHA.764@TK2MSFTNGXA01.phx.gbl... >>> Hi Ryan, >>> >>> In addition, I suggest you put all relational tables in a DataSet. There >>> is >>> no requirement for using how many DataSets on a form. It's just for your >>> convenience, which makes the developer clear of relations between >>> tables. >>> HTH. >>> >>> Kevin Yu >>> Microsoft Online Community Support >>> >>> ============================================================================ >>> ========================== >>> When responding to posts, please "Reply to Group" via your newsreader so >>> that others may learn and benefit from your issue. >>> ============================================================================ >>> ========================== >>> >>> (This posting is provided "AS IS", with no warranties, and confers no >>> rights.) >>> >> >> > > Yea actually the User table is only needed as a lookup table to find the
User name (users are backend users of the application, not applicants which are stored in the person table). So would you suggest putting lookup tables in datasets by themselves (for drop-down boxes usually)? Since lookup tables usually only need one or two fields from a table. Ryan Show quoteHide quote "Cor Ligthert [MVP]" <notmyfirstn***@planet.nl> wrote in message news:OT4DYOIkGHA.4508@TK2MSFTNGP05.phx.gbl... > Ryan, > > I would create datasets containing the main table (have a look at paging > so that you can limit them in lenght) and supporting tables. Probably do > you in most cases only need the name from the user, so loading that with > all its data is a waste of time. I assume that the user table contains > probably only the extra data not in the person data. Probably do you need > that data nowhere except there where you modify that and to logon, so it > can probably only contains forever only one row that you have selected > with a where clause (I don't know if you do it already however try to use > uniqueindentifiers which are Guids). > > Probably is a lot related round a user, than try to get only the data from > that user with a where clause in your dataset. > > (In my idea does a datasets not reflect your organisation as a database > does. A dataset is for me reflecting the way your data is used) > > Just my thoughts, > > Cor > > "Ryan" <Tyveil@newsgroups.nospam> schreef in bericht > news:u0UcI8HkGHA.3484@TK2MSFTNGP03.phx.gbl... >> Just to give you all an example of one of my forms and an idea of what >> type of dataset I need: >> >> I have an application form which displays an application sent in by a >> person (applying for a position on a public board). The form needs to >> display information from all of the following relational tables: >> >> The Person table containing contact information for that person. >> The Application table containing general information about the >> application (when and how it was submitted) >> The Application_mm_Board table which contains a record for each board >> this application is being submitted for. >> The Board table which is needed for the name of each board the applicant >> is applying for. >> The Application_mm_Question table which contains a record for each >> question asked on this application >> The ApplicationQuestion table which stores the questions themselves. >> The ApplicationAnswer table which stores the applicants answers to each >> question. >> The User table which shows who submitted this application if it was input >> manually by a user. >> >> As you can see a even a single dataset for this one form becomes rather >> large. Do you think I should split it up even further for different >> functions on the form? Maybe a different dataset for separate >> datagridviews on the form? >> >> Thanks, >> Ryan >> >> "Cor Ligthert [MVP]" <notmyfirstn***@planet.nl> wrote in message >> news:uvlSaMEkGHA.4040@TK2MSFTNGP05.phx.gbl... >>> Kevin and Marina, >>> >>> I had not seen that you both had answered already while replying. >>> >>> Probably something in my eyes. >>> >>> :-) >>> >>> Others I had written "in addition". >>> >>> So by this. >>> >>> Cor >>> >>> "Kevin Yu [MSFT]" <v-k***@online.microsoft.com> schreef in bericht >>> news:%2335ZNWCkGHA.764@TK2MSFTNGXA01.phx.gbl... >>>> Hi Ryan, >>>> >>>> In addition, I suggest you put all relational tables in a DataSet. >>>> There is >>>> no requirement for using how many DataSets on a form. It's just for >>>> your >>>> convenience, which makes the developer clear of relations between >>>> tables. >>>> HTH. >>>> >>>> Kevin Yu >>>> Microsoft Online Community Support >>>> >>>> ============================================================================ >>>> ========================== >>>> When responding to posts, please "Reply to Group" via your newsreader >>>> so >>>> that others may learn and benefit from your issue. >>>> ============================================================================ >>>> ========================== >>>> >>>> (This posting is provided "AS IS", with no warranties, and confers no >>>> rights.) >>>> >>> >>> >> >> > > Yes
And if they change and you have too the complete information in a where table, than change that table too and don't update it. Cor Show quoteHide quote "Ryan" <Tyveil@newsgroups.nospam> schreef in bericht news:OGw2OXIkGHA.1208@TK2MSFTNGP02.phx.gbl... > Yea actually the User table is only needed as a lookup table to find the > User name (users are backend users of the application, not applicants > which are stored in the person table). So would you suggest putting > lookup tables in datasets by themselves (for drop-down boxes usually)? > Since lookup tables usually only need one or two fields from a table. > > Ryan > > "Cor Ligthert [MVP]" <notmyfirstn***@planet.nl> wrote in message > news:OT4DYOIkGHA.4508@TK2MSFTNGP05.phx.gbl... >> Ryan, >> >> I would create datasets containing the main table (have a look at paging >> so that you can limit them in lenght) and supporting tables. Probably do >> you in most cases only need the name from the user, so loading that with >> all its data is a waste of time. I assume that the user table contains >> probably only the extra data not in the person data. Probably do you need >> that data nowhere except there where you modify that and to logon, so it >> can probably only contains forever only one row that you have selected >> with a where clause (I don't know if you do it already however try to use >> uniqueindentifiers which are Guids). >> >> Probably is a lot related round a user, than try to get only the data >> from that user with a where clause in your dataset. >> >> (In my idea does a datasets not reflect your organisation as a database >> does. A dataset is for me reflecting the way your data is used) >> >> Just my thoughts, >> >> Cor >> >> "Ryan" <Tyveil@newsgroups.nospam> schreef in bericht >> news:u0UcI8HkGHA.3484@TK2MSFTNGP03.phx.gbl... >>> Just to give you all an example of one of my forms and an idea of what >>> type of dataset I need: >>> >>> I have an application form which displays an application sent in by a >>> person (applying for a position on a public board). The form needs to >>> display information from all of the following relational tables: >>> >>> The Person table containing contact information for that person. >>> The Application table containing general information about the >>> application (when and how it was submitted) >>> The Application_mm_Board table which contains a record for each board >>> this application is being submitted for. >>> The Board table which is needed for the name of each board the applicant >>> is applying for. >>> The Application_mm_Question table which contains a record for each >>> question asked on this application >>> The ApplicationQuestion table which stores the questions themselves. >>> The ApplicationAnswer table which stores the applicants answers to each >>> question. >>> The User table which shows who submitted this application if it was >>> input manually by a user. >>> >>> As you can see a even a single dataset for this one form becomes rather >>> large. Do you think I should split it up even further for different >>> functions on the form? Maybe a different dataset for separate >>> datagridviews on the form? >>> >>> Thanks, >>> Ryan >>> >>> "Cor Ligthert [MVP]" <notmyfirstn***@planet.nl> wrote in message >>> news:uvlSaMEkGHA.4040@TK2MSFTNGP05.phx.gbl... >>>> Kevin and Marina, >>>> >>>> I had not seen that you both had answered already while replying. >>>> >>>> Probably something in my eyes. >>>> >>>> :-) >>>> >>>> Others I had written "in addition". >>>> >>>> So by this. >>>> >>>> Cor >>>> >>>> "Kevin Yu [MSFT]" <v-k***@online.microsoft.com> schreef in bericht >>>> news:%2335ZNWCkGHA.764@TK2MSFTNGXA01.phx.gbl... >>>>> Hi Ryan, >>>>> >>>>> In addition, I suggest you put all relational tables in a DataSet. >>>>> There is >>>>> no requirement for using how many DataSets on a form. It's just for >>>>> your >>>>> convenience, which makes the developer clear of relations between >>>>> tables. >>>>> HTH. >>>>> >>>>> Kevin Yu >>>>> Microsoft Online Community Support >>>>> >>>>> ============================================================================ >>>>> ========================== >>>>> When responding to posts, please "Reply to Group" via your newsreader >>>>> so >>>>> that others may learn and benefit from your issue. >>>>> ============================================================================ >>>>> ========================== >>>>> >>>>> (This posting is provided "AS IS", with no warranties, and confers no >>>>> rights.) >>>>> >>>> >>>> >>> >>> >> >> > > Ryan,
One single dataset will probably be very inefficient. Where you cut it is up to you. Version 2005 goes back to the datatable (the equivalent of the recordset) approach. Although that is for external reasons always wrapped inside a dataset. I hope this gives an idea, do you want to know more specific things, than reply Cor Show quoteHide quote "Ryan" <Tyveil@newsgroups.nospam> schreef in bericht news:eTyeUr%23jGHA.1208@TK2MSFTNGP02.phx.gbl... > I'm learning when it comes to Datasets. Should I just have a single > dataset to handle my entire application data or should I use multiple - a > dataset for each function or form within my application? Is the data > actually written from and queried to the dataset only when needed per a > table adapter? It looks like the table adapters .fill method is only > invoked when required, so I assume a single dataset would suffice. Is > this right? > > Thanks, > Ryan > 
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