We use Access as database in our sample code. If you use other dababase, the only difference is the database string. Both imports are needed in your aspx code.
<%@ import Namespace="System.Data" %>
<%@ import Namespace="System.Data.OleDb" %>
Sample I. open and close database, directly use SQL to read data.
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string strResultsHolder = "";
string strSQL = "SELECT employID, firstnamel Lastname FROM employee";
String strConnection = "Provider=Microsoft.Jet.OleDb.4.0;";
strConnection += @"Data Source=c:\employeeDB.mdb";
OleDbConnection objConnection = new OleDbConnection(strConnection);
OleDbCommand objCommand = new OleDbCommand(strSQL, objConnection);
OleDbDataReader objDataReader = null;//dataReader hold the data
objConnection.Open();
objDataReader = objCommand.ExecuteReader();//read data to DataReader
while (objDataReader.Read() == true)
{
strResultsHolder += objDataReader["firstname"];
strResultsHolder += " ";
strResultsHolder += objDataReader["lastname"];
strResultsHolder += "<br/>";
}
objDataReader.Close();
objConnection.Close();
//Another way, use datagrid control to hold data, no connection Close is needed
//datagrid.DataSource = objCommand.ExecuteReader(CommandBehavior.CloseConnection)
//datagrid.DataBind();
--------------------------- - Use symbol @, we do not need use escape charactor '\'. |
Sample II. open database, read data in DataSet, close database. You can freely use this disconnected dataset.
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string strSQL = "SELECT firstname,lastname FROM employee";
String strConnection = "Provider=Microsoft.Jet.OleDb.4.0;";
strConnection += @"Data Source=c:\employeeDB.mdb";
OleDbConnection objConnection = new OleDbConnection(strConnection);
DataSet objDataSet = new DataSet();
OleDbDataAdapter objAdapter = new OleDbDataAdapter(strSQL, objConnection);
//fetch the data to dataset, and give it a name we will use later
objAdapter.Fill(objDataSet, "emp");
//retrieve data from dataset, objDataSet.Tables["emp"],
//copy to datagrid control
datagrid.DataSource=objDataSet.Tables["emp"].DefaultView;
datagrid.DataBind();
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