... Create and fill the DataSet counting elapsed ticks.
DataSet ds = CreateDataSet( );
[ Team LiB ]
Recipe 9.9 ImprovingPerformanceWhileFillingaDataSet
Problem
Given aDataSet containing ... Cursors.Default;
}
private DataSet CreateDataSet( )
{
DataSet ds = new DataSet( );
// Create the Orders table.
DataTable dtOrders = new DataTable(ORDERS_TABLE);
DataColumnCollection ... contained DataTable
objects are used, if specified. A DataAdapter is used to fill a specified DataSet
with data from the Orders and Order Details tables in the Northwind database. Ten
iterations...
... steady flow
refrigeration cycle model consisting of a constant thermal-capacity heating branch, two constant thermal-
capacity cooling branches and two adiabatic branches with the consideration ... endoreversible refrigeration cycle model consisting of a
constant thermal-capacity heating branch, two constant thermal-capacity cooling branches and two
adiabatic branches is viewed as a production ... 1 and 2 is a
heating branch with constant thermal capacity (mass flow rate and specific heat product)
in
C
; the
processes between 3 and 4, and 4 and 5 are two cooling branches with constant...
... You can use this table
[ Team LiB ]
Recipe 5.3 Converting a DataReader to aDataSet
Problem
You need to transfer data from a DataReader to a DataSet.
Solution
Create a DataTable schema ... while( dr.Read( ))
{
// Read the row from the DataReader into an array.
dr.GetValues(aData);
// Add the row from the array to the DataTable.
dataTable.Rows.Add(aData);
}
}
}
while (dr.NextResult( ... (DataColumn[])pkCols.ToArray(typeof(DataColumn));
// Add the table to the DataSet.
ds.Tables.Add(dataTable);
object[] aData = new object[dataTable.Columns.Count];
// Read all rows from the DataReader.
while( dr.Read(...
... Team LiB ]
Recipe 2.2 Building aDataSet Programmatically
Problem
You want to build aDataSet programmatically—including adding tables, columns,
primary keys, and relations—from a schema ... the DataSet identifying the tables, columns, indexes, constraints, and data
relations that need to be created.
2. Create a new DataSet, naming it in the constructor.
3. Create a new DataTable, ... new DataSet( "MyDataSet");
// Build the Orders (parent) table.
DataTable parentTable = new DataTable("Orders");
DataColumnCollection cols = parentTable.Columns;
// Add...
...
private void encryptButton_Click(object sender, System.EventArgs e)
{
DataSet ds = new DataSet( );
SqlDataAdapter da;
// Fill the Order table and add it to the DataSet.
da = new ... SchemaType.Source);
da.Fill(orderTable);
ds.Tables.Add(orderTable);
// Fill the OrderDetails table and add it to the DataSet.
da = new SqlDataAdapter("SELECT * FROM [Order Details]", ... CryptoStreamMode.Read);
ds.ReadXml(cs, XmlReadMode.ReadSchema);
cs.Close( );
dataGrid.DataSource = ds.DefaultViewManager;
}
catch(Exception ex)
{
dataGrid.DataSource = null;
MessageBox.Show(ex.Message,...
... COM interop.
While the data can be loaded into aDataSet in this way, there is no way to reconcile the
changes made to the data in the DataSet with the data source underlying the ADO object. ... DataTable dt = new DataTable("Orders");
(new OleDbDataAdapter( )).Fill(dt, rs);
conn.Close( );
// Bind the default view of the dt to the grid.
dataGrid.DataSource = dt.DefaultView; ... dt.DefaultView;
Discussion
One of the overloads of the OLE DB .NET DataAdapter.Fill( ) method accepts an ADO
Recordset or Record object. The COM component that returns an ADO Recordset or
Record object...
... Close the reader and connection.
dr.Close( );
conn.Close( );
// Load the Orders data into a table in a DataSet.
DataSet ds = new DataSet( );
SqlDataAdapter da = new SqlDataAdapter(sqlText, ... xmlDoc.LoadXml(adoXml);
// Create a namespace manager for the XML document.
XmlNamespaceManager nm = new XmlNamespaceManager(xmlDoc.NameTable);
// Add ADO prefixes.
nm.AddNamespace("s", ... OleDbDataAdapter oleDa = new OleDbDataAdapter( );
DataTable dt = new DataTable("Orders");
oleDa.Fill(dt, rs);
// Bind the default view of the table to the grid.
dataGrid.DataSource...
... second, and a period of one second.
Update Button.Click
Uses a DataAdapter to update changes made to the first DataTable
back to the data
source.
CheckRefreshDataSet( )
This method is called ... and a timer.
The sample code contains two event handlers and one method:
Form.Load
Sets up the sample by creating a DataTable containing the Categories table from
the Northwind database. ... database. The default view of the table is bound to a data grid on
the form. A second DataTable with the auto-refreshing functionality is created that
also contains the Categories table from the...
... it again. The DataSet in this case
is referred to as a disconnected DataSet as it doesn't maintain an active connection to the
database. Disconnected DataSet objects act as a data cache ... time. Instead, a better approach is to connect to the database, fetch the data into
a DataSet object, and then disconnect again. The user can browse the data in the DataSet
and make any changes ... Configuration Wizard. Notice that this
class is defined in a namespace called NorthwindDataSetTableAdapters (as are all
the other TableAdapter classes for this DataSet) . The second statement...
... requirements?
Very easily; space reallocation is rarely a challenge.
Adequately; space reallocation is always a challenge, but one that we are
usually able to deal with.
With great difficulty; our data ... is close to full capacity and any space
reallocation is a major headache.
Cable Management
What types of cabling do you utilize in your data center? Please check all that apply.
Unshielded
Unshielded ...
Other:____________
Section A
A Planning Guide for Network Managers
Page 4
Section A
Worksheet: Analyzing Your Data Center Design
and Layout
The key to maintaining a high -performance data network is the design and layout...
... You can push these changes to the database using the
following example:
mySqlDataAdapter.Update(myDataSet);
All your changes to myDataSet are pushed to the database as part of the transaction ... Each of the Command objects in mySqlDataAdapter will now use mySqlTransaction.
Let's say you added, modified, and removed some rows from a DataTable contained in a
DataSet named myDataSet. ...
mySqlTransaction.
Note A transaction is rolled back by default; therefore, you should always explicitly
commit or roll back your transaction using Commit() or Rollback() to make it clear
what...
... "ORDER BY CustomerID";
SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter();
mySqlDataAdapter.SelectCommand = mySqlCommand;
DataSet myDataSet = new DataSet( );
mySqlConnection.Open(); ... "ORDER BY CustomerID";
SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter();
mySqlDataAdapter.SelectCommand = mySqlCommand;
DataSet myDataSet = new DataSet( );
mySqlConnection.Open(); ... Chapter 16
, "Using SQL Server's XML Support."
Using the WriteXml() Method
Let's say you have aDataSet object named myDataSet. Assume that myDataSet has a
DataTable that...
...
[ Team LiB ]
Recipe 2.1 Retrieving Hierarchical Data into aDataSet
Problem
You want to fill aDataSet with parent and related child data, even if the DataSet already
has a schema that ... parent table, Orders, is bound to
a data grid on the form.
Load DataSet Button.Click
Starts by clearing the data from the DataSet and refreshing the data grid.
DataAdapter objects are created ... System.EventArgs e)
{
// Remove all data from the DataSet and refresh the grid.
ds.Clear( );
dataGrid.Refresh( );
// Create parent and child data adapters.
SqlDataAdapter daParent =...
... tables. The XML schema and data for the DataSet
is written both to a file and to a text box on the form.
Read Button.Click
Creates aDataSet and reads in schema and data from a file containing ... Team LiB ]
Recipe 8.2 Saving and Loading aDataSet from XML
Problem
You need to save aDataSet as an XML file and create aDataSet from an XML file.
Solution
Use the XmlTextWriter and ... DataTable orderTable = new DataTable(ORDERS_TABLE);
da.FillSchema(orderTable, SchemaType.Source);
da.Fill(orderTable);
ds.Tables.Add(orderTable);
// Fill the OrderDetails table and add...
... If the username and password check out, then the GetUserInfo method is
called, passing the username once again. The first table from the returned dataset
is assigned to the DataSource property ...
xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
- <xs:element name="NewDataSet" msdata:IsDataSet="true">
- <xs:complexType>
- <xs:choice maxOccurs="unbounded"> ... from a data table. 2. If the goal is to include all the columns in
the table and accept the Password column, then when other columns are
added, you will not have to touch the code because the...