private static void Entry(ContosoUniversity190324Entities db)
{
db.Database.Log = (msg) => Console.WriteLine(msg);
//var dept = new Department()
//{
// DepartmentID = 17,
// Name = "酷奇資訊",
// Budget = 18000,
// StartDate = new DateTime(2008, 1, 1, 0, 0, 0)
//};
//var entry = db.Entry(dept);
// ---複製並修改
var dept = db.Departments.Find(1);
dept.Name = "修改後名稱";
var entry = db.Entry(dept);
entry.State = EntityState.Added;
db.SaveChanges();
Console.WriteLine(entry.State);
}
private static void CCourseWithRelation(ContosoUniversity190324Entities db)
{
// 顯示程式碼
db.Database.Log = (msg) => Console.WriteLine(msg);
var course = db.Courses.Find(1);
course.Instructors.Add(new Person()
{
FirstName = "will",
LastName = "Huang",
HireDate = DateTime.Now,
Discriminator = "XXX"
});
// enity錯誤處理
try
{
db.SaveChanges();
}
catch (DbEntityValidationException e)
{
var sb = new StringBuilder();
foreach (var ex in e.EntityValidationErrors)
{
foreach (var ve in ex.ValidationErrors)
{
sb.AppendLine($"欄位: {ve.PropertyName} 發生錯誤: {ve.ErrorMessage} ");
}
}
//Console.WriteLine(e.EntityValidationErrors);
throw new Exception(sb.ToString(), e);
}
}
private static void AsNoTracking(ContosoUniversity190324Entities db)
{
var data = db.Courses.AsNoTracking();
foreach (var item in data)
{
Console.WriteLine(item.Title);
}
}
private static void ConcurrencyModel(ContosoUniversity190324Entities db)
{
db.Database.Log = (msg) => Console.WriteLine(msg);
var dept = db.Departments.Find(1);
dept.Budget++;
Console.ReadLine();
db.SaveChanges();
}
private static void partialEntryEdit(ContosoUniversity190324Entities db)
{
db.Database.Log = (msg) => Console.WriteLine(msg);
var dept = new Department()
{
Name = "酷奇資訊",
Budget = 18000,
StartDate = new DateTime(2008, 1, 1, 0, 0, 0)
};
db.Departments.Add(dept);
db.SaveChanges();
}
private static void SelectCourWithRelation2(ContosoUniversity190324Entities db)
{
// 顯示程式碼
db.Database.Log = (msg) => Console.WriteLine(msg);
// 最好是都取消lazyloading
db.Configuration.LazyLoadingEnabled = false;
foreach (var item in db.Courses.Include(p => p.Department).Select(p => new { CourseTitle = p.Title, DeptTitle = p.Department.Name }))
{
Console.WriteLine(item.CourseTitle);
Console.Write('\t' + item.DeptTitle + '\n');
}
}
private static void Main(string[] args)
{
var db = new ContosoUniversity190324Entities();
//CCourseWithRelation2(db);
//AsNoTracking(db);
//Attach(db);
//Entry(db);
//partialEntryEdit(db);
ConcurrencyModel(db);
}
private static void CRUDCourWithRelation1(ContosoUniversity190324Entities db)
{
// 顯示程式碼
db.Database.Log = (msg) => Console.WriteLine(msg);
Department dept = new Department
{
Name = "TEST",
Budget = 100,
StartDate = DateTime.Now,
ModifyOn = DateTime.Now
};
dept.Courses.Add(new Course
{
Title = "Test 課程1",
Credits = 1,
Department = dept
});
dept.Courses.Add(new Course
{
Title = "Test 課程2",
Credits = 2,
Department = dept
});
db.Departments.Add(dept);
db.SaveChanges();
Console.WriteLine("產生部門id: " + dept.DepartmentID);
Console.WriteLine("產生部門名稱: " + dept.Name);
foreach (var c in dept.Courses)
{
Console.WriteLine("CourseId: " + c.CourseID.ToString());
}
var data = db.Departments.Find(dept.DepartmentID);
data.Name = "Adjust Test";
db.SaveChanges();
Console.WriteLine("部門名稱調整為: " + data.Name);
//db.Departments.Remove(data);
//db.SaveChanges();
//Console.WriteLine("部門 " + data.Name + " 已刪除");
}
private static void SelectCourWithRelation1(ContosoUniversity190324Entities db)
{
// 顯示程式碼
db.Database.Log = (msg) => Console.WriteLine(msg);
var dept = from p in db.Departments
select p;
foreach (var item in dept)
{
Console.WriteLine(item.Name);
foreach (var item1 in item.Courses)
{
Console.Write('\t' + item1.Title + '\n');
}
}
}
private static void Attach(ContosoUniversity190324Entities db)
{
var dept = new Department()
{
DepartmentID = 17,
Name = "酷奇資訊",
Budget = 18000,
StartDate = new DateTime(2008, 1, 1, 0, 0, 0)
};
db.Departments.Attach(dept);
// 狀態變為unchanged
//db.SaveChanges();
// >> 這時候不會變更
dept.Name = "123";
db.SaveChanges();
}
private static void SelectCourWithRelation(ContosoUniversity190324Entities db)
{
// 顯示程式碼
db.Database.Log = (msg) => Console.WriteLine(msg);
// Contains用法(相當於like % %)
var c = db.Courses.Where(p => p.Title.Contains("Git")).ToList();
//var c = db.Courses.Where(p => p.Title.StartsWith("Git")).ToList();
//var c = db.Courses.Where(p => p.Title.EndsWith("Git")).ToList();
// 只選擇單一欄位跑SQL by Linq
//var c = db.Courses.Where(p => p.Title.StartsWith("Git")).Select(p => new { p.Title });
// 只選擇單一欄位跑SQL
//var c = from p in db.Courses
// where p.Title.StartsWith("Git")
// select new
// {
// p.Title
// };
// 只選擇單一欄位跑SQL+排序
//var c = from p in db.Courses
// where p.Title.StartsWith("Git")
// orderby p.Credits descending
// select new
// {
// p.Title
// };
foreach (var item in c)
{
//Console.WriteLine(item.Title);
Console.WriteLine(item.Department.Name + '\t' + item.Title);
}
}
