Linq-插入insert

1.简单形式

说明：new一个对象，使用InsertOnSubmit方法将其加入到对应的集合中，使用SubmitChanges()提交到数据库。

NorthwindDataContext db = new NorthwindDataContext();
var newCustomer = new Customer
{
    CustomerID = "MCSFT",
    CompanyName = "Microsoft",
    ContactName = "John Doe",
    ContactTitle = "Sales Manager",
    Address = "1 Microsoft Way",
    City = "Redmond",
    Region = "WA",
    PostalCode = "98052",
    Country = "USA",
    Phone = "(425) 555-1234",
    Fax = null
};
db.Customers.InsertOnSubmit(newCustomer);
db.SubmitChanges();

语句描述：使用InsertOnSubmit方法将新客户添加到Customers 表对象。调用SubmitChanges 将此新Customer保存到数据库。

2.一对多关系

说明：Category与Product是一对多的关系，提交Category(一端)的数据时，LINQ to SQL会自动将Product(多端)的数据一起提交。

var newCategory = new Category
{
    CategoryName = "Widgets",
    Description = "Widgets are the ……"
};
var newProduct = new Product
{
    ProductName = "Blue Widget",
    UnitPrice = 34.56M,
    Category = newCategory
};
db.Categories.InsertOnSubmit(newCategory);
db.SubmitChanges();

语句描述：使用InsertOnSubmit方法将新类别添加到Categories表中，并将新Product对象添加到与此新Category有外键关系的Products表中。调用SubmitChanges将这些新对象及其关系保存到数据库。

3.多对多关系

说明：在多对多关系中，我们需要依次提交。

var newEmployee = new Employee
{
    FirstName = "Kira",
    LastName = "Smith"
};
var newTerritory = new Territory
{
    TerritoryID = "12345",
    TerritoryDescription = "Anytown",
    Region = db.Regions.First()
};
var newEmployeeTerritory = new EmployeeTerritory
{
    Employee = newEmployee,
    Territory = newTerritory
};
db.Employees.InsertOnSubmit(newEmployee);
db.Territories.InsertOnSubmit(newTerritory);
db.EmployeeTerritories.InsertOnSubmit(newEmployeeTerritory);
db.SubmitChanges();

语句描述：使用InsertOnSubmit方法将新雇员添加到Employees 表中，将新Territory添加到Territories表中，并将新EmployeeTerritory对象添加到与此新Employee对象和新Territory对象有外键关系的EmployeeTerritories表中。调用SubmitChanges将这些新对象及其关系保持到数据库。