How DataSet works?

[Mojtaba Faridzad]

Hi,

I am a newbie! I am wondering how DataSet keeps the data. I am using MySQL
as database engine. when I use "Fill" method to set a table in DataSet, does
C# retreive all data (base on Select statement) to the local computer's
memory? if we retreive 100,000 records, does it take a while to load them?

another question that I am not sure about it. can we create a table in
DataSet without relation to MySQL database? I'd like to create a temporary
table on a local computer's memory (not on the server). is that possible?
how?

thanks in advance

[Cowboy \(Gregory A. Beamer\) [MVP]]

The entire set is loaded into memory on the machine using the DataSet. It is
pulled as XML. For huge recordsets, you may notice it taking awhile. I
cannot comment on 100,000 records, as I do not know the column lengths. It
could be slow.

The ADO.NET model allows you to create a new Table programatically.

1. Create a DataTable object

DataTable dt = new DataTable();

2. Create columns for the data table

DataColumn dc = new DataColumn("ColumnName");
dt.Columns.Add(dc);

3. Create a new row and fill each column

DataRow dr = new DataRow();
dr["ColumnName"] = "some value";
dt.Rows.Add(dr);

4. Repeat step three until you have all rows filled

dr = new DataRow();
dr["ColumnName"] = "some other value";
dt.Rows.Add(dr);

5. Add DataTable to DataSet

ds.Tables.Add(dt);

--
Gregory A. Beamer
MVP; MCP: +I, SE, SD, DBA

************************************************
Think Outside the Box!
************************************************
"Mojtaba Faridzad" <mf*******@hotmail.com> wrote in message
news:ek**************@TK2MSFTNGP10.phx.gbl...

Hi,

I am a newbie! I am wondering how DataSet keeps the data. I am using MySQL
as database engine. when I use "Fill" method to set a table in DataSet, does C# retreive all data (base on Select statement) to the local computer's
memory? if we retreive 100,000 records, does it take a while to load them?
another question that I am not sure about it. can we create a table in
DataSet without relation to MySQL database? I'd like to create a temporary table on a local computer's memory (not on the server). is that possible?
how?

thanks in advance

[Mojtaba Faridzad]

thanks for your answer!

have you ever needed to show more than 100,000 records (one of my table has
450,000 records) in a DataGrid? how did you deal with it? I had this
problem before and I had to break the data to each page. when user clicks on
next page, I retreive the next page from the server. I am wondering there is
a better method in C# or not.

about your code, i typed it and it worked fine (with minor changes). after
using the temporary table, should we use Clear method to get rid of the
table? or like creating a connection, we can add the table in using( ) block
? or we have to call Dispose?

thanks again

"Cowboy (Gregory A. Beamer) [MVP]" <No************@comcast.netNoSpamM> wrote
in message news:u3**************@tk2msftngp13.phx.gbl...

The entire set is loaded into memory on the machine using the DataSet. It
is
pulled as XML. For huge recordsets, you may notice it taking awhile. I
cannot comment on 100,000 records, as I do not know the column lengths. It
could be slow.

The ADO.NET model allows you to create a new Table programatically.

1. Create a DataTable object

DataTable dt = new DataTable();

2. Create columns for the data table

DataColumn dc = new DataColumn("ColumnName");
dt.Columns.Add(dc);

3. Create a new row and fill each column

DataRow dr = new DataRow();
dr["ColumnName"] = "some value";
dt.Rows.Add(dr);

4. Repeat step three until you have all rows filled

dr = new DataRow();
dr["ColumnName"] = "some other value";
dt.Rows.Add(dr);

5. Add DataTable to DataSet

ds.Tables.Add(dt);

--
Gregory A. Beamer
MVP; MCP: +I, SE, SD, DBA

************************************************
Think Outside the Box!
************************************************
"Mojtaba Faridzad" <mf*******@hotmail.com> wrote in message
news:ek**************@TK2MSFTNGP10.phx.gbl...

Hi,

I am a newbie! I am wondering how DataSet keeps the data. I am using
MySQL
as database engine. when I use "Fill" method to set a table in DataSet,

does

C# retreive all data (base on Select statement) to the local computer's
memory? if we retreive 100,000 records, does it take a while to load

them?

another question that I am not sure about it. can we create a table in
DataSet without relation to MySQL database? I'd like to create a

temporary

table on a local computer's memory (not on the server). is that possible?
how?

thanks in advance

[Cowboy \(Gregory A. Beamer\) [MVP]]

With ASP.NET, you can use the paging features. I am not as familiar with the
Windows version of the DataGrid, howver.

I have seen some articles on faking paging by linking primary keys from the
last record and the first record, if you need to roll your own.

If you are creating a table that could potentially exist, consider checking
the DataSet to see if it is there and clearing it. You can also add rows to
a table that already exists, if you are inclined. This can be sent back to
the database through an Update() on the DataAdapter you created the DataSet
with.

Hope this helps.

--
Gregory A. Beamer
MVP; MCP: +I, SE, SD, DBA

************************************************
Think Outside the Box!
************************************************
"Mojtaba Faridzad" <mf*******@hotmail.com> wrote in message
news:uC**************@TK2MSFTNGP12.phx.gbl...

thanks for your answer!

have you ever needed to show more than 100,000 records (one of my table has 450,000 records) in a DataGrid? how did you deal with it? I had this
problem before and I had to break the data to each page. when user clicks on next page, I retreive the next page from the server. I am wondering there is a better method in C# or not.

about your code, i typed it and it worked fine (with minor changes). after
using the temporary table, should we use Clear method to get rid of the
table? or like creating a connection, we can add the table in using( ) block ? or we have to call Dispose?

thanks again

"Cowboy (Gregory A. Beamer) [MVP]" <No************@comcast.netNoSpamM> wrote in message news:u3**************@tk2msftngp13.phx.gbl...

The entire set is loaded into memory on the machine using the DataSet. It is
pulled as XML. For huge recordsets, you may notice it taking awhile. I
cannot comment on 100,000 records, as I do not know the column lengths. It could be slow.

The ADO.NET model allows you to create a new Table programatically.

1. Create a DataTable object

DataTable dt = new DataTable();

2. Create columns for the data table

DataColumn dc = new DataColumn("ColumnName");
dt.Columns.Add(dc);

3. Create a new row and fill each column

DataRow dr = new DataRow();
dr["ColumnName"] = "some value";
dt.Rows.Add(dr);

4. Repeat step three until you have all rows filled

dr = new DataRow();
dr["ColumnName"] = "some other value";
dt.Rows.Add(dr);

5. Add DataTable to DataSet

ds.Tables.Add(dt);

--
Gregory A. Beamer
MVP; MCP: +I, SE, SD, DBA

************************************************
Think Outside the Box!
************************************************
"Mojtaba Faridzad" <mf*******@hotmail.com> wrote in message
news:ek**************@TK2MSFTNGP10.phx.gbl...

Hi,

I am a newbie! I am wondering how DataSet keeps the data. I am using
MySQL
as database engine. when I use "Fill" method to set a table in DataSet,

does

C# retreive all data (base on Select statement) to the local computer's
memory? if we retreive 100,000 records, does it take a while to load

them?

another question that I am not sure about it. can we create a table in
DataSet without relation to MySQL database? I'd like to create a

temporary

table on a local computer's memory (not on the server). is that possible? how?

thanks in advance