public bool UpdateProduct(ProductEntity product)
{
// TODO: call data access layer to update product
// first check to see if it is a valid price
if (product.UnitPrice <= 0)
return false;
// ProductName can't be empty
else if (product.ProductName == null
|| product.ProductName.Length == 0)
return false;
// QuantityPerUnit can't be empty
else if (product.QuantityPerUnit == null
|| product.QuantityPerUnit.Length == 0)
return false;
// then validate other properties
else
{
ProductEntity productInDB = GetProduct(product.ProductID);
// invalid product to update
if (productInDB == null)
return false;
// a product can't be discontinued if there are
// non-fulfilled orders
if (product.Discontinued == true
&& productInDB.UnitsOnOrder > 0)
return false;
else
return productDAO.UpdateProduct(product);
}
}
public ProductEntity GetProduct(int id)
{
/*
// TODO: connect to DB to retrieve product
ProductEntity p = new ProductEntity();
p.ProductID = id;
p.ProductName = "fake product name from data access layer";
p.UnitPrice = (decimal)30.00;
return p;
*/
ProductEntity p = null;
using (SqlConnection conn = new SqlConnection(connectionString))
{
SqlCommand comm = new SqlCommand();
comm.CommandText = "select * from Products where ProductID=" + id;
comm.Connection = conn;
conn.Open();
SqlDataReader reader = comm.ExecuteReader();
if (reader.HasRows)
{
reader.Read();
p = new ProductEntity();
p.ProductID = id;
p.ProductName = (string)reader["ProductName"];
p.QuantityPerUnit = (string)reader["QuantityPerUnit"];
p.UnitPrice = (decimal)reader["UnitPrice"];
p.UnitsInStock = (short)reader["UnitsInStock"];
p.UnitsOnOrder = (short)reader["UnitsOnOrder"];
p.ReorderLevel = (short)reader["ReorderLevel"];
p.Discontinued = (bool)reader["Discontinued"];
}
return p;
}
}
public ProductEntity GetProduct(int id)
{
// TODO: call data access layer to retrieve product
ProductEntity p = new ProductEntity();
p.ProductID = id;
p.ProductName = "fake product name from business logic layer";
p.UnitPrice = (decimal)20.00;
if (id > 50) p.UnitsOnOrder = 30;
return p;
}
public bool UpdateProduct(ProductEntity product)
{
// TODO: connect to DB to update product
using (SqlConnection conn = new SqlConnection(connectionString))
{
SqlCommand cmd = new SqlCommand("UPDATE products SET ProductName=@name,QuantityPerUnit=@unit,UnitPrice=@price,Discontinued=@discontinued WHERE ProductID=@id", conn);
cmd.Parameters.AddWithValue("@name", product.ProductName);
cmd.Parameters.AddWithValue("@unit", product.QuantityPerUnit);
cmd.Parameters.AddWithValue("@price", product.UnitPrice);
cmd.Parameters.AddWithValue("@discontinued", product.Discontinued);
cmd.Parameters.AddWithValue("@id", product.ProductID);
conn.Open();
int numRows = cmd.ExecuteNonQuery();
if (numRows != 1)
return false;
}
return true;
}