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dotnet ado.net : Connected vs disconnected application
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> I want to populate a ComboBox from a table. I know how to do this only for > disconnected applications. Is it possible to use a connected application > to populate a ComboBox? Yes -- Here is how -- http://codebetter.com/blogs/sahil.malik/archive/2004/12/11/36078.aspx [quoted text, click to view] > If I can use any method, which one should I use? How should I decide which > one to preffer among them two? Here are my thoughts about connnected vs. disconnected. (SqlDataAdapter is disconnected and SqlCommand/SqlDataReaders are connected). http://codebetter.com/blogs/sahil.malik/archive/2005/01/28/48711.aspx HTH :-) - Sahil Malik http://codebetter.com/blogs/sahil.malik/ [quoted text, click to view] "Nicolae Fieraru" <nospam@please.com> wrote in message news:uwm9m$0BFHA.3588@TK2MSFTNGP11.phx.gbl... > Hi All, > > I read in a book that a program can connect to a database using two > different types of connections to a database. In case the program can > maintain a direct connection, classes such as OleDbConnection, > OleDbCommand and OleDbDataReader can be used. > The other option is to create a disconnected application, using an > OleDbDataSet. > and an OleDbDataAdapter. > > I want to populate a ComboBox from a table. I know how to do this only for > disconnected applications. Is it possible to use a connected application > to populate a ComboBox? If I can use any method, which one should I use? > How should I decide which one to preffer among them two? > > Regards, > Nicolae >
Nicolae,
With ADONET when you get data or write data there is forever a connection. When you are reading data, than the connection is there (when you do it well) as long as the datareader is reading (which is as well used in the fill from a dataset). Of course can you populate with the datareader a Combobox using the items.add in. However the combobox itself is disconnected. The contrapart is OleDB what is a connected situation. In OleDB is a recordset used which is constantly keeping connection with the Database. A concept that looks nice however has a lot of problems had to be overcome. Therefore the new direction is choosen, the dataset (not to mix up with the recordset because it holds relations and datatables where the last you can compare as disconnected recordsets). A simple example why disconnected, think on a PDA. I hope this gives some idea's Cor
Hi Nicolae,
A .NET Framework data provider is used for connecting to a database,=20 executing commands, and retrieving results. Those results are either = processed=20 directly, or placed in an ADO.NET DataSet in order to be exposed to the = user=20 in an ad-hoc manner, combined with data from multiple sources, or = remoted between=20 tiers. You can use the Data Reader to populate your Combo Box..A data reader = reads a forward-only,=20 read-only stream of data from a data source.So, incase you don't want = any manipulation in the data and=20 have to read all at once, you should go for Data Reader as it is more = economical in terms of load on your application. The DataSet object is central to supporting disconnected, distributed = data scenarios with ADO.NET.=20 The DataSet is a memory-resident representation of data that provides a = consistent relational programming=20 model regardless of the data source. It can be used with multiple and = differing data sources, used with XML=20 data, or used to manage data local to the application. The DataSet = represents a complete set of data including=20 related tables, constraints, and relationships among the tables. An ADO.NET DataSet contains a collection of zero or more tables = represented by DataTable objects.=20 The DataTableCollection contains all the DataTable objects in a DataSet. So,in cases you want a light weight connection or data from more than = one table,DataSet is the option for you. HTH Mona [quoted text, click to view] "Nicolae Fieraru" <nospam@please.com> wrote in message =
news:uwm9m$0BFHA.3588@TK2MSFTNGP11.phx.gbl... > Hi All, >=20 > I read in a book that a program can connect to a database using two=20 > different types of connections to a database. In case the program can=20 > maintain a direct connection, classes such as OleDbConnection, = OleDbCommand=20 > and OleDbDataReader can be used. > The other option is to create a disconnected application, using an=20 > OleDbDataSet. > and an OleDbDataAdapter. >=20 > I want to populate a ComboBox from a table. I know how to do this only = for=20 > disconnected applications. Is it possible to use a connected = application to=20 > populate a ComboBox? If I can use any method, which one should I use? = How=20 > should I decide which one to preffer among them two? >=20 > Regards, > Nicolae=20 >=20
Hi All,
I read in a book that a program can connect to a database using two different types of connections to a database. In case the program can maintain a direct connection, classes such as OleDbConnection, OleDbCommand and OleDbDataReader can be used. The other option is to create a disconnected application, using an OleDbDataSet. and an OleDbDataAdapter. I want to populate a ComboBox from a table. I know how to do this only for disconnected applications. Is it possible to use a connected application to populate a ComboBox? If I can use any method, which one should I use? How should I decide which one to preffer among them two? Regards, Nicolae
Thank you Sahil, I read your blog. I consider the information presented in
there to be useful. I also had a look at the code with the datareader and I found a few good ideas in there. Regards, Nicolae
Thank you Mona, you described very well the advantages of using a =
DataSet.=20 I managed to fill in the combobox using a datareader as well, but now = I've got another problem.=20 I will post another question. Regards, Nicolae [quoted text, click to view] "Mona" <Mona@discussions.microsoft.com> wrote in message = Hi Nicolae,news:u0iNom3BFHA.3824@TK2MSFTNGP10.phx.gbl... A .NET Framework data provider is used for connecting to a database,=20 executing commands, and retrieving results. Those results are either = processed=20 directly, or placed in an ADO.NET DataSet in order to be exposed to = the user=20 in an ad-hoc manner, combined with data from multiple sources, or = remoted between=20 tiers. You can use the Data Reader to populate your Combo Box..A data reader = reads a forward-only,=20 read-only stream of data from a data source.So, incase you don't want = any manipulation in the data and=20 have to read all at once, you should go for Data Reader as it is more = economical in terms of load on your application. The DataSet object is central to supporting disconnected, distributed = data scenarios with ADO.NET.=20 The DataSet is a memory-resident representation of data that provides = a consistent relational programming=20 model regardless of the data source. It can be used with multiple and = differing data sources, used with XML=20 data, or used to manage data local to the application. The DataSet = represents a complete set of data including=20 related tables, constraints, and relationships among the tables. An ADO.NET DataSet contains a collection of zero or more tables = represented by DataTable objects.=20 The DataTableCollection contains all the DataTable objects in a = DataSet. So,in cases you want a light weight connection or data from more than = one table,DataSet is the option for you. HTH Mona [quoted text, click to view] "Nicolae Fieraru" <nospam@please.com> wrote in message =
news:uwm9m$0BFHA.3588@TK2MSFTNGP11.phx.gbl... > Hi All, >=20 > I read in a book that a program can connect to a database using two=20 > different types of connections to a database. In case the program = can=20 > maintain a direct connection, classes such as OleDbConnection, = OleDbCommand=20 > and OleDbDataReader can be used. > The other option is to create a disconnected application, using an=20 > OleDbDataSet. > and an OleDbDataAdapter. >=20 > I want to populate a ComboBox from a table. I know how to do this = only for=20 > disconnected applications. Is it possible to use a connected = application to=20 > populate a ComboBox? If I can use any method, which one should I = use? How=20 > should I decide which one to preffer among them two? >=20 > Regards, > Nicolae=20 >=20
[quoted text, click to view] "Cor Ligthert" <notmyfirstname@planet.nl> wrote in message news:uwXJDh3BFHA.3644@TK2MSFTNGP15.phx.gbl... > Of course can you populate with the datareader a Combobox using the > items.add in. Hi Cor. I figured it out in the meantime and this the way I've done it. [quoted text, click to view] > For me it is ok if the combobox is disconnected.> However the combobox itself is disconnected. > [quoted text, click to view] > I hope this gives some ideas > > Cor Thanks for your reply, Nicolae
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