public void Working_With_Current_Orginal_DatabaseValues()
{
using (var context = new CodeCampContext(TestHelpers.TestDatabaseName))
{
var speaker = context.Speakers.Find(1);
var entity = context.Entry(speaker);
// create a second DbContext to simulate change from another user.
using (var context2 = new CodeCampContext(TestHelpers.TestDatabaseName))
{
var changeSpeaker = context2.Speakers.Find(1);
changeSpeaker.Bio = "Bio has changed while you were out...";
context2.SaveChanges();
}
Console.WriteLine("Current Values before edit");
TestHelpers.WritePropertyValues(entity.CurrentValues);
speaker.Email = "*****@*****.**";
speaker.TwitterAlias = "@steve";
Console.WriteLine("Current Values after edit");
TestHelpers.WritePropertyValues(entity.CurrentValues);
Console.WriteLine("Orginal Values");
TestHelpers.WritePropertyValues(entity.OriginalValues);
Console.WriteLine("Database Values (trip to database)");
TestHelpers.WritePropertyValues(entity.GetDatabaseValues());
}
}
public void CRUD()
{
// Note: The reason for the seperate using blocks is to simulate seperate calls to database.
int speakerID;
// Create new speaker
using(var context = new CodeCampContext(TestHelpers.TestDatabaseName))
{
var speaker = new Speaker
{
FirstName = "Test",
LastName = "Speaker"
};
context.Speakers.Add(speaker);
context.SaveChanges();
speakerID = speaker.Id;
Assert.IsTrue(speakerID != 0);
}
// Read and Update speaker
using(var context = new CodeCampContext(TestHelpers.TestDatabaseName))
{
var query = from s in context.Speakers
where s.Id == speakerID
select s;
var speaker = query.FirstOrDefault();
Assert.IsNotNull(speaker);
speaker.Email = "*****@*****.**";
context.SaveChanges();
var checkSpeaker = query.FirstOrDefault();
Assert.AreEqual(speaker.Email, checkSpeaker.Email);
}
// Delete: with out pulling record from database first
using (var context = new CodeCampContext(TestHelpers.TestDatabaseName))
{
var speaker = new Speaker {Id = speakerID};
context.Speakers.Attach(speaker);
context.Speakers.Remove(speaker);
// can also be expressed as a single statement
// context.Entry(speaker).State = EntityState.Deleted;
context.SaveChanges();
var query = from s in context.Speakers
where s.Id == speakerID
select s;
var checkSpeaker = query.FirstOrDefault();
Assert.IsNull(checkSpeaker);
}
}
public void CRUD_With_Relationships()
{
// Add a new presentation through a Speaker's presentation collection.
using (var context = new CodeCampContext(TestHelpers.TestDatabaseName))
{
Presentation presentation = new Presentation
{
Title = "Another presentation about .NET"
};
Speaker speaker = context.Speakers.FirstOrDefault(s => s.LastName == "Pugh");
speaker.Presentations.Add(presentation);
context.SaveChanges();
var query = from p in context.Presentations
where p.Speaker.LastName == "Pugh"
select p;
Assert.AreEqual(2, query.Count());
}
// Add a speaker to a new presentation.
using (var context = new CodeCampContext(TestHelpers.TestDatabaseName))
{
var query = from s in context.Speakers
where s.Id == 1
select s;
Speaker speaker = query.FirstOrDefault();
Presentation presentation = new Presentation
{
Title = "More about REST",
Speaker = speaker
};
context.Presentations.Add(presentation);
context.SaveChanges();
// Requery Speaker, this time get presentations.
speaker = query.Include(s => s.Presentations).FirstOrDefault();
Assert.AreEqual(2, speaker.Presentations.Count);
Console.WriteLine("New Presentation added to existing Speaker");
foreach (var presentation1 in context.Presentations.Local)
{
Console.WriteLine("Speaker: {0}, Presentation: {1}", presentation1.Speaker.FirstName, presentation1.Title);
}
Console.WriteLine();
// Change speaker of presentation
var speaker2 = context.Speakers.Include(s => s.Presentations).FirstOrDefault(s => s.Id == 8);
presentation.Speaker = speaker2;
context.SaveChanges();
Console.WriteLine("Presenation moved to a different speaker");
foreach (var presentation1 in context.Presentations.Local.OrderBy(p=>p.Speaker.LastName))
{
Console.WriteLine("Speaker: {0}, Presentation: {1}", presentation1.Speaker.FirstName, presentation1.Title);
}
Console.WriteLine();
// Remove Presentation by setting Speaker to null in Presentation record.
presentation.Speaker = null; // This only works because Speaker is not required. If it was required an exception would be thrown on save.
// Remove Presentation by removing it from the Presentation navigation property in Speaker;
Presentation presentation2 = speaker2.Presentations.FirstOrDefault();
speaker2.Presentations.Remove(presentation2);
context.SaveChanges();
Console.WriteLine("Presenation removed. No longer assigned to any speaker.");
foreach (var presentation1 in context.Presentations.Local)
{
Console.WriteLine("Speaker: {0}, Presentation: {1}",
presentation1.Speaker != null ? presentation1.Speaker.FirstName : "No Speaker Assigned",
presentation1.Title);
}
}
}
public void ComlexTypes_With_Current_Orginal_DatabaseValues()
{
using (var context = new CodeCampContext(TestHelpers.TestDatabaseName))
{
var codeCamp = context.CodeCampEvents.FirstOrDefault();
var entity = context.Entry(codeCamp);
// create a second DbContext to simulate change from another user.
using (var context2 = new CodeCampContext(TestHelpers.TestDatabaseName))
{
var codeCamp2 = context2.CodeCampEvents.FirstOrDefault();
codeCamp2.Location.StreetAddress2 = "Street 2 Changed";
context2.SaveChanges();
}
Console.WriteLine("Current Values before edit");
TestHelpers.WritePropertyValues(entity.CurrentValues);
codeCamp.Location.StreetAddress2 = "Suite 101";
Console.WriteLine("Current Values after edit");
TestHelpers.WritePropertyValues(entity.CurrentValues);
Console.WriteLine("Orginal Values");
TestHelpers.WritePropertyValues(entity.OriginalValues);
Console.WriteLine("Database Values (trip to database)");
TestHelpers.WritePropertyValues(entity.GetDatabaseValues());
}
}
