public static void UpdateProduct(Product oldProduct, Product newProduct)
{
//instantiate conn object to hold connection string.
SqlConnection conn = DatabaseDB.GetConnection();
//Update query, with optimistic concurancy.
string strUp =
"UPDATE Products " +
"SET Description = @newDescription, " +
"UnitPrice = @newPrice " +
"WHERE ProductCode = @ProductCode " +
"AND Description = @oldDescription " +
"AND UnitPrice = @oldPrice";
//declare commandn object and set sql statement and connections string.
SqlCommand cmd = new SqlCommand(strUp, conn);
//declare paramaters with old and new values.
cmd.Parameters.AddWithValue("@newDescription", newProduct.Description);
cmd.Parameters.AddWithValue("@newPrice", newProduct.Price);
cmd.Parameters.AddWithValue("@oldDescription", oldProduct.Description);
cmd.Parameters.AddWithValue("@oldProductCode", oldProduct.ProdCode);
cmd.Parameters.AddWithValue("@oldPrice", oldProduct.Price);
cmd.Parameters.AddWithValue("@ProductCode", oldProduct.ProdCode);
try
{
//open database connection
conn.Open();
//update record
cmd.ExecuteNonQuery();
//display a successful execution.
MessageBox.Show("Record Successfully Updated", "Updated");
}
catch (Exception ex)
{
throw ex;
}
finally
{
conn.Close();
}
}
public static void AddProduct(Product product)
{
//set a new connection object
SqlConnection conn = DatabaseDB.GetConnection();
//set string for sql statement
string strIns =
"INSERT INTO Products " +
"(ProductCode, Description, UnitPrice) " +
"Values (@Code, @Description, @UnitPrice)";
//set command object to the sql statement and connection
SqlCommand cmd = new SqlCommand(strIns, conn);
//identify paramaters and the property which will populate the value.
cmd.Parameters.AddWithValue("@Code", product.ProdCode);
cmd.Parameters.AddWithValue("@Description", product.Description);
cmd.Parameters.AddWithValue("@UnitPrice", product.Price);
try
{
//open the connection to the database.
conn.Open();
//execute the insert statement
cmd.ExecuteNonQuery();
//inform user the record has been inserted.
MessageBox.Show("Record Added", "Success");
}
catch (Exception ex)
{
//thow exception if insert fails.
throw ex;
}
finally
{
//close the database connection.
conn.Close();
}
}
public static void SelectProduct(Product product)
{
//set sql connection string
SqlConnection conn = DatabaseDB.GetConnection();
//Set Select query to string. select query gets users input for product code.
string strSel =
"SELECT * FROM Products " +
"WHERE ProductCode = @ProductCode";
//declare command object and assign sql query and connection
SqlCommand cmd = new SqlCommand(strSel, conn);
cmd.Parameters.AddWithValue("@ProductCode", product.ProdCode);
try
{
//open database
conn.Open();
//execute Reader for the select statement
SqlDataReader dr = cmd.ExecuteReader();
while (dr.Read())
{
product.ProdCode = dr["ProductCode"].ToString();
product.Description = dr["Description"].ToString();
product.Price = Convert.ToDecimal(dr["UnitPrice"]);
}
}
catch (Exception ex)
{
//throw error
throw ex;
}
finally
{
//close database connection
conn.Close();
}
}
public static List <string> SelectAllProducts()
{
//declare List to hold values.
List <string> lstProductCode = new List <string>();
//set sql connection string
SqlConnection conn = DatabaseDB.GetConnection();
//Set Select query to string. select query gets users input for product code.
string strSel =
"SELECT ProductCode FROM Products";
//declare command object and assign sql query and connection
SqlCommand cmd = new SqlCommand(strSel, conn);
try
{
//open database
conn.Open();
//execute Reader for the select statement
SqlDataReader dr = cmd.ExecuteReader();
while (dr.Read())
{
lstProductCode.Add(dr["ProductCode"].ToString());
}
return(lstProductCode);
}
catch (Exception ex)
{
//throw error
throw ex;
}
finally
{
//close database connection
conn.Close();
}
}
public static void DeleteProduct(Product product)
{
//set new connection object.
SqlConnection conn = DatabaseDB.GetConnection();
//set string strDelete to equal the sql delete syntax
string strDelete =
"DELETE FROM Products " +
"WHERE ProductCode = @ProductCode";
//declare command object and set the query and connection.
SqlCommand cmd = new SqlCommand(strDelete, conn);
//declare paramaters and paramater value
cmd.Parameters.AddWithValue("@ProductCode", product.ProdCode);
//try executing the delete
try
{
//open database connection.
conn.Open();
//Execute Command NonQuery.
cmd.ExecuteNonQuery();
//Display Success
MessageBox.Show("Successfully Deleted!", "Row Removed");
}
catch (Exception ex)
{
throw ex;
}
finally
{
conn.Close();
}
}
