Additional information: A network-related or instance-specific error occurred while establishing a connection to SQL Server.
The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections.
(provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified) da.SelectCommand = cmd; da.Fill(ds);
The code:
public string LogNotification { get; set; }
public bool ConfirmLogin(string id, string pw)
{
using (SqlConnection con = new SqlConnection("Data Source=C:\\RegistrationMDB.mdb"))
{
SqlDataAdapter da = new SqlDataAdapter();
DataSet ds = new DataSet();
SqlCommand cmd = new SqlCommand("SELECT ID, PASSWORD FROM Students WHERE ID = @ID OR PASSWORD = @PASSWORD", con);
da.SelectCommand = cmd;
da.Fill(ds);
cmd.CommandType = CommandType.Text;
cmd.Parameters.Add("@ID", SqlDbType.VarChar).Value = id;
cmd.Parameters.Add("@PASSWORD", SqlDbType.VarChar).Value = pw;
foreach (DataRow dr in ds.Tables[0].Rows)
{
iD = (dr["@ID"].ToString());
password = dr["@PASSWORD"].ToString();
}
if (iD == id && password == pw)
{
return true;
}
else
{
LogNotification = "ID/Password is incorrect";
return false;
}
}
}
Database Code;
//++++++++++++++++ DATABASE Data Elements +++++++++++++++++
public System.Data.OleDb.OleDbDataAdapter OleDbDataAdapter;
public System.Data.OleDb.OleDbCommand OleDbSelectCommand;
public System.Data.OleDb.OleDbCommand OleDbInsertCommand;
public System.Data.OleDb.OleDbCommand OleDbUpdateCommand;
public System.Data.OleDb.OleDbCommand OleDbDeleteCommand;
public System.Data.OleDb.OleDbConnection OleDbConnection;
public String cmd;
public void DBSetup(){
// +++++++++++++++++++++++++++ DBSetup function +++++++++++++++++++++++++++
// This DBSetup() method instantiates all the DB objects needed to access a DB,
// including OleDbDataAdapter, which contains 4 other objects(OlsDbSelectCommand,
// oleDbInsertCommand, oleDbUpdateCommand, oleDbDeleteCommand.) And each
// Command object contains a Connection object and an SQL string object.
OleDbDataAdapter = new System.Data.OleDb.OleDbDataAdapter();
OleDbSelectCommand = new System.Data.OleDb.OleDbCommand();
OleDbInsertCommand = new System.Data.OleDb.OleDbCommand();
OleDbUpdateCommand = new System.Data.OleDb.OleDbCommand();
OleDbDeleteCommand = new System.Data.OleDb.OleDbCommand();
OleDbConnection = new System.Data.OleDb.OleDbConnection();
OleDbDataAdapter.DeleteCommand = OleDbDeleteCommand;
OleDbDataAdapter.InsertCommand = OleDbInsertCommand;
OleDbDataAdapter.SelectCommand = OleDbSelectCommand;
OleDbDataAdapter.UpdateCommand = OleDbUpdateCommand;
OleDbConnection.ConnectionString = "Jet OLEDB:Global Partial Bulk Ops=2;Jet OLEDB:Reg"+
"istry Path=;Jet OLEDB:Database L" +
"ocking Mode=1;Data Source=C:\\RegistrationMDB.mdb;J" +
"et OLEDB:Engine Type=5;Provider=Microsoft.Jet.OLEDB.4.0;Jet OLEDB:System datab" +
"ase=;Jet OLEDB:SFP=False;persist security info=False;Extended Properties=;Mode=S" +
"hare Deny None;Jet OLEDB:Encrypt Database=False;Jet OLEDB:Create System Database=False;Jet " +
"OLEDB:Don't Copy Locale on Compact=False;Jet OLEDB:Compact Without Replica Repai" +
"r=False;User ID=Admin;Jet OLEDB:Global Bulk Transactions=1";
}
public void SelectDB(String id)
{ //++++++++++++++++++++++++++ SELECT +++++++++++++++++++++++++
DBSetup();
cmd = "Select * from Students where ID = " + iD;
OleDbDataAdapter.SelectCommand.CommandText = cmd;
OleDbDataAdapter.SelectCommand.Connection = OleDbConnection;
Console.WriteLine(cmd);
try {
OleDbConnection.Open();
System.Data.OleDb.OleDbDataReader dr;
dr = OleDbDataAdapter.SelectCommand.ExecuteReader();
dr.Read();
id=iD;
setPassword(dr.GetValue(1)+"");
setEMail(dr.GetValue(2)+"");
setGpa(Double.Parse(dr.GetValue(3)+""));
}
catch (Exception ex)
{
Console.WriteLine(ex);
}
finally
{
OleDbConnection.Close();
}
}
public void InsertDB() {
// +++++++++++++++++++++++++++ INSERT +++++++++++++++++++++++++++++++
DBSetup();
cmd = "INSERT into Students values(" + getID() + "," +
"'" + getPassword() + "'," +
"'" + getEMail() + "'," +
"'" + getGpa() + ")";
OleDbDataAdapter.InsertCommand.CommandText = cmd;
OleDbDataAdapter.InsertCommand.Connection = OleDbConnection;
Console.WriteLine(cmd);
try
{
OleDbConnection.Open();
int n = OleDbDataAdapter.InsertCommand.ExecuteNonQuery();
if (n==1)
Console.WriteLine("Data Inserted");
else
Console.WriteLine("ERROR: Inserting Data");
}
catch (Exception ex)
{
Console.WriteLine(ex);
}
finally
{
OleDbConnection.Close();
}
}
public void updateDB()
{
//++++++++++++++++++++++++++ UPDATE +++++++++++++++++++++++++
cmd = "Update Students set ID = '" + getID() + "'," +
"Password = '" + getPassword() + "', " +
"Email = '" + getEMail() + "', " +
"GPA = " + getGpa();
OleDbDataAdapter.UpdateCommand.CommandText = cmd;
OleDbDataAdapter.UpdateCommand.Connection = OleDbConnection;
Console.WriteLine(cmd);
try
{
OleDbConnection.Open();
int n = OleDbDataAdapter.UpdateCommand.ExecuteNonQuery();
if (n==1)
Console.WriteLine("Data Updated");
else
Console.WriteLine("ERROR: Updating Data");
}
catch (Exception ex)
{
Console.WriteLine(ex);
}
finally
{
OleDbConnection.Close();
}
}
public void deleteDB()
{
//++++++++++++++++++++++++++ DELETE +++++++++++++++++++++++++
cmd = "Delete from Students where ID = " + getID();
OleDbDataAdapter.DeleteCommand.CommandText = cmd;
OleDbDataAdapter.DeleteCommand.Connection = OleDbConnection;
Console.WriteLine(cmd);
try
{
OleDbConnection.Open();
int n = OleDbDataAdapter.DeleteCommand.ExecuteNonQuery();
if (n==1)
Console.WriteLine("Data Deleted");
else
Console.WriteLine("ERROR: Deleting Data");
}
catch (Exception ex)
{
Console.WriteLine(ex);
}
finally
{
OleDbConnection.Close();
}
}
