public void AsNoTrackingDoesntReturnDeletedData()
{
// Create initial data in database
int sueID = CustomerHelpers.AddCustomer("Sue", "VA");
using (var context1 = new EFTestContext())
{
// Get Sue's customer entity
var sue = context1.Customers.Where(c => c.ID == sueID).AsNoTracking().First();
// Name should be "Sue"
sue.Name.Should().Be("Sue");
// Update data in other context (simulating a second user)
using (var context2 = new EFTestContext())
{
context2.Customers.First(c => c.ID == sueID).Name = "Susan";
context2.SaveChanges();
}
// Verify the name has been updated in the database
using (var context3 = new EFTestContext())
{
var sueIsUpdated = context3.Customers.First(c => c.ID == sueID);
sueIsUpdated.Name.Should().Be("Susan");
}
// But our original context has the stale data cached
var sueStillUpdated = context1.Customers.First(c => c.ID == sueID);
sueStillUpdated.Name.Should().Be("Susan");
}
// Cleanup
CustomerHelpers.DeleteCustomer(sueID);
}
public void UsingANewContextWillRetrieveUpdatedData()
{
// Create initial data in database
int sueID = CustomerHelpers.AddCustomer("Sue", "VA");
using (var context1 = new EFTestContext())
{
// Get Sue's customer entity
var sue = context1.Customers.Where(c => c.ID == sueID).AsNoTracking().First();
// Name should be "Sue"
sue.Name.Should().Be("Sue");
}
// Update data in other context (simulating a second user)
using (var context2 = new EFTestContext())
{
context2.Customers.First(c => c.ID == sueID).Name = "Susan";
context2.SaveChanges();
}
// Use a new context to retrieve the updated record
using (var context3 = new EFTestContext())
{
var sueIsUpdated = context3.Customers.First(c => c.ID == sueID);
sueIsUpdated.Name.Should().Be("Susan");
}
// Cleanup
CustomerHelpers.DeleteCustomer(sueID);
}
public void AsNoTrackingDoesntAddDataToCache()
{
// Create initial data in database
int sueID = CustomerHelpers.AddCustomer("Sue", "VA");
using (var context1 = new EFTestContext())
{
// Get Sue's customer entity
var sue = context1.Customers.Where(c => c.ID == sueID).AsNoTracking().First();
// Name should be "Sue"
sue.Name.Should().Be("Sue");
// Update data in other context (simulating a second user)
using (var context2 = new EFTestContext())
{
context2.Customers.First(c => c.ID == sueID).Name = "Susan";
context2.SaveChanges();
}
// Verify the name has been updated in the database
using (var context3 = new EFTestContext())
{
var sueIsUpdated = context3.Customers.First(c => c.ID == sueID);
sueIsUpdated.Name.Should().Be("Susan");
}
// We can retrieve the updated record from context1, which tells us that the
// cache on context1 is empty (before we retrieved the data
var sueStillUpdated = context1.Customers.First(c => c.ID == sueID);
sueStillUpdated.Name.Should().Be("Susan");
}
// Cleanup
CustomerHelpers.DeleteCustomer(sueID);
}
public void CacheKnowsWhenDataIsAddedToDb()
{
// Create initial data in database
int sueID = CustomerHelpers.AddCustomer("Sue", "VA");
using (var context1 = new EFTestContext())
{
// Get count of customers in Virginia
var numInVABefore = context1.Customers.Where(c => c.State == "VA").ToList().Count;
// Add new customer using separate context (simulating a second user)
int jamesID = CustomerHelpers.AddCustomer("James", "VA");
// Verify new record exists in database using another context
using (var context3 = new EFTestContext())
{
var jamesExists = context3.Customers.FirstOrDefault(c => c.ID == jamesID);
jamesExists.Should().NotBeNull();
}
// Our original context shows the new record when queried
var numInVAAfter = context1.Customers.Where(c => c.State == "VA").ToList().Count;
numInVAAfter.Should().Be(numInVABefore + 1);
}
// Cleanup
CustomerHelpers.DeleteCustomer(sueID);
}
public void QueryWithOverwriteChangesWillUpdateCacheFromDatabase()
{
// Create initial data in database
int sueID = CustomerHelpers.AddCustomer("Sue", "VA");
using (var context1 = new EFTestContext())
{
// Get Sue's customer entity, adding it to the cache
var sue = context1.Customers.First(c => c.ID == sueID);
// Name should be "Sue"
sue.Name.Should().Be("Sue");
// Update data in other context (simulating a second user)
using (var context2 = new EFTestContext())
{
context2.Customers.First(c => c.ID == sueID).Name = "Susan";
context2.SaveChanges();
}
// Verify the name has been updated in the database
using (var context3 = new EFTestContext())
{
var sueIsUpdated = context3.Customers.First(c => c.ID == sueID);
sueIsUpdated.Name.Should().Be("Susan");
}
// Get Sue's customer entity using MergeOptions.OverwriteChanges, updating the entity in the cache
var objectContext = ((IObjectContextAdapter)context1).ObjectContext;
var objectQuery = objectContext.CreateObjectSet <Customer>().Where(c => c.ID == sueID);
// Set the MergeOptions to overwrite what is in the cache
(objectQuery as ObjectQuery <Customer>).MergeOption = MergeOption.OverwriteChanges;
var sueFromOriginalContext = objectQuery.First();
// Verify we retrieved the updated data
sueFromOriginalContext.Name.Should().Be("Susan");
// Get Sue from the cache again, verifying that the cache has been updated, this tme
// querying without the OverwriteChanges MergeOption
var sueFromOriginalContextWithoutOverwriteChanges = context1.Customers.First(c => c.ID == sueID);
sueFromOriginalContextWithoutOverwriteChanges.Name.Should().Be("Susan");
}
// Cleanup
CustomerHelpers.DeleteCustomer(sueID);
}
public void GetDatabaseValuesWillUpdateTheCache()
{
// Create initial data in database
int sueID = CustomerHelpers.AddCustomer("Sue", "VA");
using (var context1 = new EFTestContext())
{
// Get Sue's customer entity
var sue = context1.Customers.First(c => c.ID == sueID);
// Name should be "Sue"
sue.Name.Should().Be("Sue");
// Update data in other context (simulating a second user)
using (var context2 = new EFTestContext())
{
context2.Customers.First(c => c.ID == sueID).Name = "Susan";
context2.SaveChanges();
}
// Verify the name has been updated in the database
using (var context3 = new EFTestContext())
{
var sueIsUpdated = context3.Customers.First(c => c.ID == sueID);
sueIsUpdated.Name.Should().Be("Susan");
}
// Verify we still have stale data in the cache
var sueNotUpdated = context1.Customers.First(c => c.ID == sueID);
sueNotUpdated.Name.Should().Be("Sue");
// Use GetDatabaseValues to get a dictionary of the current db values (ignoring the cache)
DbPropertyValues sueDbValues = context1.Entry(sueNotUpdated).GetDatabaseValues();
sueDbValues["Name"].Should().Be("Susan");
// Verify we still have stale data in the cache
var sueStillNotUpdated = context1.Customers.First(c => c.ID == sueID);
sueStillNotUpdated.Name.Should().Be("Sue");
}
// Cleanup
CustomerHelpers.DeleteCustomer(sueID);
}
public void ReloadEntityWillForceEFToUpdateEntityInCache()
{
// Create initial data in database
int sueID = CustomerHelpers.AddCustomer("Sue", "VA");
using (var context1 = new EFTestContext())
{
// Get Sue's customer entity
var sue = context1.Customers.Where(c => c.ID == sueID).First();
// Name should be "Sue"
sue.Name.Should().Be("Sue");
// Update data in other context (simulating a second user)
using (var context2 = new EFTestContext())
{
context2.Customers.First(c => c.ID == sueID).Name = "Susan";
context2.SaveChanges();
}
// Verify the name has been updated in the database
using (var context3 = new EFTestContext())
{
var sueIsUpdated = context3.Customers.First(c => c.ID == sueID);
sueIsUpdated.Name.Should().Be("Susan");
}
// Verify our original context has the old data
var sueNotUpdated = context1.Customers.First(c => c.ID == sueID);
sueNotUpdated.Name.Should().Be("Sue");
// Force EF to reload Sue's data
context1.Entry(sue).Reload();
// Retrieve the updated record from context1, which shows us
// that the cache has been updated
var sueUpdatedInOriginalContext = context1.Customers.First(c => c.ID == sueID);
sueUpdatedInOriginalContext.Name.Should().Be("Susan");
}
// Cleanup
CustomerHelpers.DeleteCustomer(sueID);
}
public void StandardQueryWillNotOverwriteCacheAfterQueryWithOverwriteChanges()
{
// Create initial data in database
int sueID = CustomerHelpers.AddCustomer("Sue", "VA");
using (var context1 = new EFTestContext())
{
// Get Sue's customer entity using MergeOptions.OverwriteChanges, placing the entity in the cache
var objectContext = ((IObjectContextAdapter)context1).ObjectContext;
var objectQuery = objectContext.CreateObjectSet <Customer>().Where(c => c.ID == sueID);
// Set the MergeOptions to overwrite what is in the cache
(objectQuery as ObjectQuery <Customer>).MergeOption = MergeOption.OverwriteChanges;
var sueNowInCache = objectQuery.First();
// Verify we retrieved the original data
sueNowInCache.Name.Should().Be("Sue");
// Update data in other context (simulating a second user)
using (var context2 = new EFTestContext())
{
context2.Customers.First(c => c.ID == sueID).Name = "Susan";
context2.SaveChanges();
}
// Verify the name has been updated in the database
using (var context3 = new EFTestContext())
{
var sueIsUpdated = context3.Customers.First(c => c.ID == sueID);
sueIsUpdated.Name.Should().Be("Susan");
}
// Get Sue from the cache without the OverwriteChanges MergeOption
var sueFromOriginalContext = context1.Customers.First(c => c.ID == sueID);
// We should see the original data, because the cache hasn't been updated
sueFromOriginalContext.Name.Should().Be("Sue");
}
// Cleanup
CustomerHelpers.DeleteCustomer(sueID);
}
public void RefreshingMultipleEntitiesInEFWillForceEFToUpdateEntityInCache()
{
try
{
// Create initial data in database
int sueID = CustomerHelpers.AddCustomer("Sue", "VA");
int jimID = CustomerHelpers.AddCustomer("Jim", "VA");
using (var context1 = new EFTestContext())
{
// Get Sue's and Jim's customer entities
var sue = context1.Customers.Where(c => c.ID == sueID).First();
var jim = context1.Customers.Where(c => c.ID == jimID).First();
// Name should be "Sue"/"Jim"
sue.Name.Should().Be("Sue");
jim.Name.Should().Be("Jim");
// Update data in other context (simulating a second user)
using (var context2 = new EFTestContext())
{
context2.Customers.First(c => c.ID == sueID).Name = "Susan";
context2.Customers.First(c => c.ID == jimID).Name = "James";
context2.SaveChanges();
}
// Verify the name has been updated in the database
using (var context3 = new EFTestContext())
{
var sueIsUpdated = context3.Customers.First(c => c.ID == sueID);
sueIsUpdated.Name.Should().Be("Susan");
var jimIsUpdated = context3.Customers.First(c => c.ID == jimID);
jimIsUpdated.Name.Should().Be("James");
}
// Verify our original context has the old data
var sueNotUpdated = context1.Customers.First(c => c.ID == sueID);
sueNotUpdated.Name.Should().Be("Sue");
var jimNotUpdated = context1.Customers.First(c => c.ID == jimID);
jimNotUpdated.Name.Should().Be("Jim");
// Force EF to refresh Sue's and Jim's data
var objectContext = ((IObjectContextAdapter)context1).ObjectContext;
var objectsToRefresh = new Customer[] { jim, sue };
objectContext.Refresh(RefreshMode.StoreWins, objectsToRefresh);
// You can also query the ObjectStateManager for the objects you need to refresh
//var objectsToRefresh = objectContext.ObjectStateManager.GetObjectStateEntries(
// EntityState.Added | EntityState.Deleted | EntityState.Modified | EntityState.Unchanged)
// .Where(e => e.EntityKey != null)
// .Select(e => e.Entity)
// .OfType<Customer>()
// .Where(c => (new int[] {sueID, jimID}).Contains(c.ID));
//objectContext.Refresh(RefreshMode.StoreWins, objectsToRefresh);
// Verify our original context has the new data
var sueUpdatedInOriginalContext = context1.Customers.First(c => c.ID == sueID);
sueUpdatedInOriginalContext.Name.Should().Be("Susan");
var jimUpdatedInOriginalContext = context1.Customers.First(c => c.ID == jimID);
jimUpdatedInOriginalContext.Name.Should().Be("James");
}
// Cleanup
CustomerHelpers.DeleteCustomer(sueID);
CustomerHelpers.DeleteCustomer(jimID);
}
catch (Exception e)
{
Console.WriteLine(e.Message);
}
}