问题
I have created the following example to test Foreign Keys and up to this point, it works well. What I would like to be able to do, is use this framework that I built to set the property of the relationship and have it Save the child object when the Parent is saved and automatically set the PrimaryKey and Foreign Key. The DataManager class exposes the Connection
public class DataManager
{
DataManager()
{
OrmLiteConfig.DialectProvider = SqliteDialect.Provider;
ConnectionString = SqliteFileDb;
updateTables();
}
private void updateTables()
{
using (var dbConn = OpenDbConnection())
{
dbConn.DropAndCreateTable<Person>();
dbConn.DropAndCreateTable<PhoneNumber>();
}
}
public static string SqliteFileDb = "~/App_Data/db.sqlite".MapAbsolutePath();
private static DataManager manager;
public static DataManager Manager {
get
{
if (manager == null)
manager = new DataManager();
return manager;
}
}
public IDbConnection InMemoryDbConnection { get; set; }
public IDbConnection OpenDbConnection(string connString = null)
{
connString = ConnectionString;
return connString.OpenDbConnection();
}
protected virtual string ConnectionString { get; set; }
protected virtual string GetFileConnectionString()
{
var connectionString = SqliteFileDb;
return connectionString;
}
}
These are my POCO's with the BaseClass used to Achieve my results:
public class Person : LiteBase
{
[AutoIncrement]
[PrimaryKey]
public int Id { get; set; }
public string Name { get; set; }
public string Surname { get; set; }
private List<PhoneNumber> numbers;
public List<PhoneNumber> PhoneNumbers {
get
{
if (numbers == null)
numbers = GetList<PhoneNumber>(p => p.Person == Id);
return numbers;
}
}
}
public class PhoneNumber
{
public string Number { get; set; }
public string Description { get; set; }
[AutoIncrement]
[PrimaryKey]
public int Id { get; set; }
[References(typeof (Person))]
public int Person { get; set; }
public void AddPerson(Person person)
{
Person = person.Id;
}
}
public class LiteBase:INotifyPropertyChanged
{
public List<T> GetList<T>(Expression< Func<T,bool>> thefunction) where T : new()
{
var objects = new List<T>();
using (var conn = Data.DataManager.Manager.OpenDbConnection())
{
objects = conn.Where<T>(thefunction);
}
return objects;
}
public T GetItem<T>(Expression<Func<T, bool>> thefunction) where T : new()
{
T obj = new T();
using (var conn = Data.DataManager.Manager.OpenDbConnection())
{
obj = conn.Where<T>(thefunction).FirstOrDefault<T>();
}
return obj;
}
public event PropertyChangedEventHandler PropertyChanged;
[NotifyPropertyChangedInvocator]
protected virtual void OnPropertyChanged(string propertyName)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
handler(this, new PropertyChangedEventArgs(propertyName));
}
}
Simple Class to Create Person and PhoneNumber objects
public class PersonManager
{
public void CreatePerson(string name, string surname, string number)
{
using (var conn = DataManager.Manager.OpenDbConnection())
{
var pnum = new PhoneNumber { Number = number };
var person = new Person
{
Name=name,
Surname = surname,
};
conn.Save<Person>(person);
var id = conn.GetLastInsertId();
person.Id = (int)id;
pnum.AddPerson(person);
conn.Save<PhoneNumber>(pnum);
}
}
public List<Person> GetPeople()
{
List<Person> people;
using (var conn = DataManager.Manager.OpenDbConnection())
{
people = conn.Select<Person>();
}
return people;
}
public List<PhoneNumber> GetNumbers()
{
List<PhoneNumber> numbers;
using (var conn = DataManager.Manager.OpenDbConnection())
{
numbers = conn.Select<PhoneNumber>();
}
return numbers;
}
}
And here is the usage:
var manager = new PersonManager();
manager.CreatePerson("John", "Doe", "12345679");
manager.CreatePerson("Jack", "Smith", "12345679");
manager.CreatePerson("Peter", "Jones", "12345679");
manager.CreatePerson("Dan", "Hardy", "12345679");
var people = manager.GetPeople();
var numbers = manager.GetNumbers();
for (int i = 0; i < people.Count; i++)
{
Console.WriteLine("{0} {1} {2}",
people[i].Name,people[i].Surname,people[i].Id);
}
for (int n = 0; n < numbers.Count; n++)
{
Console.WriteLine("PN: {0} {1}",
numbers[n].Number,numbers[n].Person);
}
for (int p = 0; p < people.Count; p++)
{
var person = people[p];
Console.WriteLine("{0}: {1} {2} {3}",
person.Id,person.Name,person.Surname,person.GetItem<PhoneNumber>(x=>x.Person==person.Id).Number);
}
The output is as I expected :
John Doe 1
Jack Smith 2
Peter Jones 3
Dan Hardy 4
PN: 12345679 1
PN: 12345679 2
PN: 12345679 3
PN: 12345679 4
1: John Doe 12345679
2: Jack Smith 12345679
3: Peter Jones 12345679
4: Dan Hardy 12345679
What I really would like to be able to do is the following:
var john = new Person
{
Name = "John",
Surname = "Smith",
PhoneNumber = new PhoneNumber { Number = "123456789" }
};
conn.Save<Person>(john);
var number = john.PhoneNumber.Number
Is this at all possible?
回答1:
By default OrmLite v3 blobs all complex types properties in a string field and you need to explicitly set all references.
In the next major v4 release (ETA late Nov 2013), OrmLite adds some support for external references with the [Reference] attribute, which lets you tell OrmLite these properties should be stored in an external table and not blobbed, e.g:
public class Customer
{
[AutoIncrement]
public int Id { get; set; }
public string Name { get; set; }
[Reference]
public CustomerAddress PrimaryAddress { get; set; }
[Reference]
public List<Order> Orders { get; set; }
}
This will allow you to call db.SaveReferences() to save the reference properties, e.g:
var customer = new Customer
{
Name = "Customer 1",
PrimaryAddress = new CustomerAddress {
AddressLine1 = "1 Humpty Street",
City = "Humpty Doo",
State = "Northern Territory",
Country = "Australia"
},
Orders = new[] {
new Order { LineItem = "Line 1", Qty = 1, Cost = 1.99m },
new Order { LineItem = "Line 2", Qty = 2, Cost = 2.99m },
}.ToList(),
};
Assert.That(customer.Id, Is.EqualTo(0)); //Id is not saved yet
//Inserts customer, populates auto-incrementing customer.Id
//Specify `references:true` to populate the ForeignKey ids and
//save the related rows as well, e.g:
db.Save(customer, references:true);
Assert.That(customer.Id, Is.GreaterThan(0));
Assert.That(customer.PrimaryAddress.CustomerId, Is.EqualTo(customer.Id));
Assert.That(customer.Orders.All(x => x.CustomerId == customer.Id));
Saving References manually
For more fine-grained control you can also choose which references you want to save, e.g:
db.Save(customer); //Doesn't save related rows
//1:1 PrimaryAddress Reference not saved yet
Assert.That(customer.PrimaryAddress.CustomerId, Is.EqualTo(0));
//1:1 PrimaryAddress Reference saved and ForeignKey id populated
db.SaveReferences(customer, customer.PrimaryAddress);
//1:Many Orders References saved and ForeignKey ids populated
db.SaveReferences(customer, customer.Orders);
Loading all related rows with the entity
You can then load the master row and all its references with db.LoadSingleById, e.g:
var dbCustomer = db.LoadSingleById<Customer>(customer.Id);
dbCustomer.PrintDump();
Assert.That(dbCustomer.PrimaryAddress, Is.Not.Null);
Assert.That(dbCustomer.Orders.Count, Is.EqualTo(2));
来源：https://stackoverflow.com/questions/19830612/servicestack-ormlite-how-can-i-achieve-automatic-setting-of-foreign-key-related