complex-dataset-update.aspx
来自「Professional ASP.NET source code」· ASPX 代码 · 共 246 行
ASPX
246 行
<%@Page Language="C#"%>
<%@Import Namespace="System.Data" %>
<%@Import Namespace="System.Data.OleDb" %>
<%@ Register TagPrefix="wrox" TagName="connect" Src="..\global\connect-strings.ascx" %>
<!DOCTYPE HTML PUBLIC "-// W3C// DTD HTML 4.0 Transitional// EN">
<html><head>
<title>Updating Complex Data with a DataSet and Stored Procedures</title>
<!-- #include file="..\global\style.inc" -->
</head>
<body bgcolor="#ffffff">
<span class="heading">Updating Complex Data with a DataSet and Stored Procedures</span><hr />
<!--------------------------------------------------------------------------->
<%-- insert connection string script --%>
<wrox:connect id="ctlConnectStrings" runat="server"/>
<div>Connection string: <b><span id="outConnect" runat="server"></span></b></div>
<div>SELECT command: <b><span id="outSelect" runat="server"></span></b></div>
<div>UPDATE command: <b><span id="outUpdate" runat="server"></span></b></div>
<div>INSERT command: <b><span id="outInsert" runat="server"></span></b></div>
<div>DELETE command: <b><span id="outDelete" runat="server"></span></b></div>
<div id="outError" runat="server"> </div>
<b>Initial contents of the Books table:</b>
<asp:datagrid id="dgrResult1" runat="server" /><p />
<b>Contents of the Books table after editing:</b>
<asp:datagrid id="dgrResult2" runat="server" /><p />
<b>Note:</b> while this page does execute the Update method of the DataSet, it does not<br />
actually change the original data. It uses a transaction that is rolled back afterwards.</br />
Otherwise, the update would prevent the code from running the next time.
<script language="C#" runat="server">
void Page_Load(Object sender, EventArgs e)
{
// get connection string from ..\global\connect-strings.ascx user control
string strConnect = ctlConnectStrings.OLEDBConnectionString;
outConnect.InnerText = strConnect; // and display it
// specify the SELECT statement to extract the data
string strSelect = "SELECT BookList.*, BookAuthors.FirstName, BookAuthors.LastName "
+ "FROM BookList INNER JOIN BookAuthors ON BookList.ISBN = BookAuthors.ISBN "
+ "WHERE BookList.ISBN LIKE '18610033%'";
outSelect.InnerText = strSelect; // and display it
// create a new DataSet object
DataSet objDataSet = new DataSet();
// create a new Connection object using the connection string
OleDbConnection objConnect = new OleDbConnection(strConnect);
// create a new DataAdapter using the connection object and select statement
OleDbDataAdapter objDataAdapter = new OleDbDataAdapter(strSelect, objConnect);
try
{
// fill the dataset with data from the DataAdapter object
objDataAdapter.Fill(objDataSet, "Books");
}
catch (Exception objError)
{
// display error details
outError.InnerHtml = "<b>* Error while accessing data</b>.<br />"
+ objError.Message + "<br />" + objError.Source;
return; // and stop execution
}
// accept the changes to "fix" the current state of the DataSet contents
objDataSet.AcceptChanges();
// declare a variable to reference the Books table
DataTable objTable = objDataSet.Tables["Books"];
// display the contents of the Books table before changing data
dgrResult1.DataSource = objTable.DefaultView;
dgrResult1.DataBind(); // and bind (display) the data
// now change some records in the Books table
objTable.Rows[0].Delete();
objTable.Rows[1]["Title"] = "Amateur Theatricals for Windows 2000";
objTable.Rows[1]["PublicationDate"] = "01-01-2003";
objTable.Rows[1]["FirstName"] = "Priscilla";
objTable.Rows[1]["LastName"] = "Prince";
objTable.Rows[2].Delete();
// add a new row using an array of values
Object[] objValsArray = new Object[5];
objValsArray[0] = "200000001";
objValsArray[1] = "Impressionist Guide to Painting Computers";
objValsArray[2] = "05-02-2002";
objValsArray[3] = "Mark";
objValsArray[4] = "Lard";
objTable.Rows.Add(objValsArray);
// display the contents of the Books table after changing the data
dgrResult2.DataSource = objTable.DefaultView;
dgrResult2.DataBind(); // and bind (display) the data
// now have to create Command objects for the DataSetCommand to
// use to update the original data. First the Update command
OleDbCommand objUpdateCommand = new OleDbCommand("BookAuthorUpdate", objConnect);
objUpdateCommand.CommandType = CommandType.StoredProcedure;
// now create the Parameter objects and add to the Command object
OleDbParameter objParam;
objParam = objUpdateCommand.Parameters.Add("ISBN", OleDbType.VarChar, 12);
objParam.Direction = ParameterDirection.Input;
objParam.SourceColumn = "ISBN";
objParam.SourceVersion = DataRowVersion.Original; // used in SQL WHERE clause
objParam = objUpdateCommand.Parameters.Add("Title", OleDbType.VarChar, 100);
objParam.Direction = ParameterDirection.Input;
objParam.SourceColumn = "Title";
objParam.SourceVersion = DataRowVersion.Current; // used in SQL SET clause
objParam = objUpdateCommand.Parameters.Add("PublicationDate", OleDbType.DBDate);
objParam.Direction = ParameterDirection.Input;
objParam.SourceColumn = "PublicationDate";
objParam.SourceVersion = DataRowVersion.Current; // used in SQL SET clause
objParam = objUpdateCommand.Parameters.Add("FirstName", OleDbType.VarChar, 50);
objParam.Direction = ParameterDirection.Input;
objParam.SourceColumn = "FirstName";
objParam.SourceVersion = DataRowVersion.Current ; // used in SQL SET clause
objParam = objUpdateCommand.Parameters.Add("LastName", OleDbType.VarChar, 50);
objParam.Direction = ParameterDirection.Input;
objParam.SourceColumn = "LastName";
objParam.SourceVersion = DataRowVersion.Current; // used in SQL SET clause
// now specify this Command object as the UpdateCommand
objDataAdapter.UpdateCommand = objUpdateCommand;
// next, the InsertCommand
OleDbCommand objInsertCommand = new OleDbCommand("BookAuthorInsert", objConnect);
objInsertCommand.CommandType = CommandType.StoredProcedure;
objParam = objInsertCommand.Parameters.Add("ISBN", OleDbType.VarChar, 12);
objParam.Direction = ParameterDirection.Input;
objParam.SourceColumn = "ISBN";
objParam.SourceVersion = DataRowVersion.Current; // used in SQL SET clause
objParam = objInsertCommand.Parameters.Add("Title", OleDbType.VarChar, 100);
objParam.Direction = ParameterDirection.Input;
objParam.SourceColumn = "Title";
objParam.SourceVersion = DataRowVersion.Current; // used in SQL SET clause
objParam = objInsertCommand.Parameters.Add("PublicationDate", OleDbType.DBDate);
objParam.Direction = ParameterDirection.Input;
objParam.SourceColumn = "PublicationDate";
objParam.SourceVersion = DataRowVersion.Current; // used in SQL SET clause
objParam = objInsertCommand.Parameters.Add("FirstName", OleDbType.VarChar, 50);
objParam.Direction = ParameterDirection.Input;
objParam.SourceColumn = "FirstName";
objParam.SourceVersion = DataRowVersion.Current; // used in SQL SET clause
objParam = objInsertCommand.Parameters.Add("LastName", OleDbType.VarChar, 50);
objParam.Direction = ParameterDirection.Input;
objParam.SourceColumn = "LastName";
objParam.SourceVersion = DataRowVersion.Current; // used in SQL SET clause
objDataAdapter.InsertCommand = objInsertCommand;
// next, the DeleteCommand
OleDbCommand objDeleteCommand = new OleDbCommand("BookAuthorDelete", objConnect);
objDeleteCommand.CommandType = CommandType.StoredProcedure;
objParam = objDeleteCommand.Parameters.Add("ISBN", OleDbType.VarChar, 12);
objParam.Direction = ParameterDirection.Input;
objParam.SourceColumn = "ISBN";
objParam.SourceVersion = DataRowVersion.Original; // used in SQL WHERE clause
objParam = objDeleteCommand.Parameters.Add("FirstName", OleDbType.VarChar, 50);
objParam.Direction = ParameterDirection.Input;
objParam.SourceColumn = "FirstName";
objParam.SourceVersion = DataRowVersion.Original; // used in SQL WHERE clause
objParam = objDeleteCommand.Parameters.Add("LastName", OleDbType.VarChar, 50);
objParam.Direction = ParameterDirection.Input;
objParam.SourceColumn = "LastName";
objParam.SourceVersion = DataRowVersion.Original; // used in SQL WHERE clause
objDataAdapter.DeleteCommand = objDeleteCommand;
// display the SQL statements that we created for the DataSet to use
string strSQL; // create a new string to store vales
// get stored proc name and source column names for each parameter
strSQL = objDataAdapter.UpdateCommand.CommandText;
foreach (OleDbParameter objP in objDataAdapter.UpdateCommand.Parameters)
strSQL += " @" + objP.SourceColumn + ",";
strSQL = strSQL.Substring(1, strSQL.Length - 1); // remove trailing comma
outUpdate.InnerText = strSQL; // and display it
// repeat the process for the Insert command
strSQL = objDataAdapter.InsertCommand.CommandText;
foreach (OleDbParameter objP in objDataAdapter.InsertCommand.Parameters)
strSQL += " @" + objP.SourceColumn + ",";
strSQL = strSQL.Substring(1, strSQL.Length - 1); // remove trailing comma
outInsert.InnerText = strSQL;
// repeat the process for the Delete command
strSQL = objDataAdapter.DeleteCommand.CommandText;
foreach (OleDbParameter objP in objDataAdapter.DeleteCommand.Parameters)
strSQL += " @" + objP.SourceColumn + ",";
strSQL = strSQL.Substring(1, strSQL.Length - 1); // remove trailing comma
outDelete.InnerText = strSQL;
// declare a variable to hold a Transaction object
OleDbTransaction objTransaction = null;
try
{
// now we're finally ready to do the update itself
// start a transaction so that we can roll back the changes
// must do this on an open Connection object
objConnect.Open();
objTransaction = objConnect.BeginTransaction();
// perform the update on the original data
objInsertCommand.Transaction = objTransaction;
objUpdateCommand.Transaction = objTransaction;
objDeleteCommand.Transaction = objTransaction;
objDataAdapter.Update(objDataSet, "Books");
// to actually update the source tables just change the next line
// to CommitTransaction() or remove the transaction altogether.
// note that you will then have to change the SELECT statement and
// code to be able to run the example again, or rebuild the
// original data from the supplied SQL scripts
objTransaction.Rollback();
}
catch (Exception objError)
{
objTransaction.Rollback();
// display error details
outError.InnerHtml = "<b>* Error while updating original data source</b>.<br />"
+ objError.Message + "<br />" + objError.Source;
return; // and stop execution
}
}
</script>
<!--------------------------------------------------------------------------->
<!-- #include file="..\global\foot.inc" -->
</body>
</html>
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