/// <summary>
/// Returns all customers from the database
/// </summary>
/// <returns></returns>
public static List <Customer> GetCustomers()
{
// Create instance of DB Context
var dbc = new BookRegistrationEntities();
// Use DB Context to retreive all customers
// Use LINQ (Language INtegrated Query) to query database
// LINQ Query Syntax
//List<Customer> customers =
// (from row in dbc.Customer
// where row.LastName == "Reynolds"
// orderby row.LastName
// select row).ToList();
//return customers;
// LINQ Method Syntax - Same query as above
List <Customer> customers =
dbc.Customer
//.Where(row => row.LastName == "Reynolds")
//.OrderByDescending(row => row.LastName)
.ToList();
return(customers);
}
public static List <Book> GetAllBooks()
{
BookRegistrationEntities context = new BookRegistrationEntities();
List <Book> allBooks = (from b in context.Book select b).ToList();
return(allBooks);
}
public static List <Customer> GetAllCustomers()
{
BookRegistrationEntities context = new BookRegistrationEntities();
List <Customer> customers = context.Customer.ToList();
return(customers);
}
/// <summary>
/// Retrieves all books sorted in alphabetical by title
/// </summary>
/// <returns></returns>
public static List <Book> GetBooks()
{
// The 'using' statement will force the compiler to create a try/finally.
// The 'finally' will dispose of the db context.
// https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/using-statement
using (var context = new BookRegistrationEntities())
{
// LINQ Method Syntax
return(context
.Book
.OrderBy(book => book.Title)
.ToList());
// LINQ Query Syntax
/*
* List<Book> books =
* (from row in context.Book
* orderby row.Title ascending
* select row).ToList();
*
* return books;
*/
// Ditto - without variable.
// A bit unclear about return type though.
/*
* return
* (from row in context.Book
* orderby row.Title ascending
* select row).ToList();
*/
}
}
public static void DeleteCustomer(Customer c)
{
using (var context = new BookRegistrationEntities())
{
context.Customer.Add(c); // "Track" with EF
context.Entry(c).State = EntityState.Deleted; // Tell EF we are removing it
int rowsAffected = context.SaveChanges(); // Update on database
// int rowsAffected is optional
}
}
public static Customer UpdateCustomer(Customer c)
{
using (var context = new BookRegistrationEntities())
{
context.Customer.Add(c); // Add to context
// Tell EF we are updating an existing entity
context.Entry(c).State = EntityState.Modified; // Tell EF it has been modified
context.SaveChanges();
return(c);
}
}
/// <summary>
/// Adds a customer. Returns the newly added customer
/// with the CustomerID populated
/// </summary>
/// <param name="c">The new Customer to be added</param>
/// <returns></returns>
public static Customer AddCustomer(Customer c)
{
using (var context = new BookRegistrationEntities())
{
context.Customer.Add(c);
// SaveChanges MUST BE CALLED for insert/update/delete
context.SaveChanges();
// Return newly added customer with CustomerID populated
return(c);
}
}