public static MyDoublyLinkedList <Customer> Load()
{
MyDoublyLinkedList <Customer> customersTable = new MyDoublyLinkedList <Customer>();
string location = "Northwind.mdb";
string connectionString = @"Provider=Microsoft.Jet.OLEDB.4.0; data source=" + location;
string sSql = "select * from Customers";
OleDbConnection con = new OleDbConnection(connectionString);
OleDbCommand myCmd = new OleDbCommand(sSql, con);
OleDbDataAdapter adapter = new OleDbDataAdapter(); //יצירת אוביקט
adapter.SelectCommand = myCmd; // command קישור ל
DataSet dataset = new DataSet(); // יצירת טבלה בזיכרון
adapter.Fill(dataset, "tblusers"); //מילוי הטבלה ומתן שם
dataset.Tables["tblusers"].PrimaryKey = new DataColumn[] { dataset.Tables["tblusers"].Columns["UserID"] };
foreach (DataRow row in dataset.Tables[0].Rows)
{
customersTable.Insert(new Customer(row[0].ToString(), row[1].ToString(),
row[2].ToString(), row[9].ToString()));
}
return(customersTable);
}
/// <summary>
/// Update Customers by given list of Customers.
/// </summary>
/// <param name="customersTable">the table is MyDoublyLinkedList</param>
public void Update(MyDoublyLinkedList <Customer> customersTable)
{
foreach (var customer in customersTable)
{
UpdateByID(customer);
}
}
//Select Customers only by single field
//and return them as MyDB
private MyDB SelectBy(string field, CustomerField selectBy)
{
MyDoublyLinkedList <Link <Customer> > newList = new MyDoublyLinkedList <Link <Customer> >();
MyDB result = new MyDB();
if (selectBy == CustomerField.CustomerID && field != "")
{
if (dictCustomerID.ContainsKey(field))
{
var line = dictCustomerID[field].Data;
result.Insert(line);
return(result);
}
}
if (selectBy == CustomerField.CompanyName && field != "")
{
if (dictCompanyName.ContainsKey(field))
{
foreach (var link in dictCompanyName[field])
{
var line = link.Data;
result.Insert(line);
}
}
}
if (selectBy == CustomerField.ContactName && field != "")
{
if (dictContactName.ContainsKey(field))
{
foreach (var link in dictContactName[field])
{
var line = link.Data;
result.Insert(line);
}
}
}
if (selectBy == CustomerField.Phone && field != "")
{
if (dictPhone.ContainsKey(field))
{
foreach (var link in dictPhone[field])
{
var line = link.Data;
result.Insert(line);
}
}
}
return(result);
}
/// <summary>
/// Insert Customers as MyDoublyLinkedList
/// and return true if some of customers ID were reserved
/// </summary>
/// <param name="customersTable">MyDoublyLinkedList<Customer></param>
/// <returns></returns>
public bool Insert(MyDoublyLinkedList <Customer> customersTable)
{
bool reservedID = false;
foreach (var customer in customersTable)
{
if (!dictCustomerID.ContainsKey(customer.CustomerID))
{
_customersTable.Insert(customer);
AddToDictionaries(_customersTable.Head, CustomerField.All);
}
else
{
reservedID = true;
}
}
return(reservedID);
}
/// <summary>
/// The constructor receive a linked list of customers
/// </summary>
/// <param name="customersTable"></param>
public MyDB(MyDoublyLinkedList <Customer> customersTable)
{
Insert(customersTable);
}