Errata

Should be ORDER BY BAModel.FullNameReverse(c) (with space between ORDER and BY); not ORDERBY BAModel.FullNameReverse(c) for Entity SQL

This comment is for EF Second Edition (EF4)

Note from the Author or Editor:
please make the suggested correction

The link cited for the book web page,

http://oreilly.com/catalog/9780596807269

does not lead to a list of errata; it is redirected to a shop.oreilly.com page. I had to search for the errata, and found the list at:

oreilly.com/catalog/errata.csp?isbn=9780596520281

Note from the Author or Editor:
thanks. it's been quite a few years so maybe they broke the link.

The sentence that reads:
"...as part of Visual Studio Service Pack 1 and .NET Service Pack 1,...

Should read:

...as part of Visual Studio 2008 Service Pack 1 and .NET Service Pack 1,...

Since it is that specific version of Visual Studio that is supported.

Note from the Author or Editor:
as part of Visual Studio 2008 Service Pack 1 and .NET 3.5 Service Pack 1,...

The instructions for opening the edmx file with the XML Editor do not work with Visual Basic 2010 Express (build 10.0.30319.1.) There is no right click option for "Open With" in the Solution Explorer. Instead the user will need to go to File -> Open File and then select "Open With" from the Open ComboBox in the FileOpen dialog.

Note from the Author or Editor:
taking this for granted since I don't have the express version...
please add to end of 2nd to last paragraph:

"If using one of the Visual Studio Express versions, you will need to open the raw XML from the File menu as there is no Open With option on the model's context menu."

-The name of the EntityContainer is "dbo," .....

Should be:
-The name of the EntityContainer is "ProgrammingEFDB1ModelStoreContainer" .....

Note from the Author or Editor:
In addition to replacing dbo with ProgrammingEFDB1ModelStoreContainer, please remove the word "schema" from the sentence. It should read:

The name of the EntityContainer is ?ProgrammingEFDB1ModelStoreContainer,? which was derived from the database name.

...without a reference to a row in the People table. ...
Should be:
...without a reference to a row in the Contact table. ...

The last sentence on page 59 mentions the following, "But as you will learn later in this book, because IQueryable inherits from ObjectQuery, it is possible to cast IQueryable to an ObjectQuery and then access those properties and methods".

The incorrect part of this statement is that "IQueryable inherits from ObjectQuery". It should say "ObjectQuery implements the IQueryable interface"

Below is the ObjectQuery class declaration.

class ObjectQuery<T> : ObjectQuery, IOrderedQueryable<T>, IQueryable<T>, IEnumerable<T>, IOrderedQueryable, IQueryable, IEnumerable, IListSource

Note from the Author or Editor:
Change sentence to:
But as you will learn later in this book, it is possible to cast IQueryable to an ObjectQuery and then access those properties and methods.

In this line of code:

var contacts = new ObjectQuery<Contact>(queryString, context);

ObjectQuery is not recognized unless you include a "using System.Data.Objects;" at the top of the file.

Minor detail, but it took me 20 minutes to find the right namespace to import. Just thought I would pass it along.

Note from the Author or Editor:
can you add a note somewhere on this page that says:

The namespaces in many of the examples are not spelled out along with the classes. Be sure to reference the appropriate namespaces at the top of your code files with Include for Visual Basic and using for C#. For example, for the ObjectQuery class you'll need Include System.Data.Objects (VB) or using System.Data.Objects; (C#).


(to editor: please use literal format for the words Include and using in the 2nd sentence and for the short statements in the last sentence (Include System.Data.Objects AND using System.Data.Objects; ))

To use a parameterized query, you need to explicitly instantiate an ObjectQuery, rather than using the CreateQuery method of the ObjectContext.


I don't think the above is true. You can pass parameters even if you instantiate the object using CreateQuery:


string qstr =
"SELECT VALUE c FROM programmingEFDB1Entities.Contacts AS c WHERE c.FirstName = @firstName";
var contacts = context.CreateQuery<Contact>(qstr);
contacts.Parameters.Add(new ObjectParameter("firstName", "Robert"));

Note from the Author or Editor:
To use a parameterized query, you can add parameters to an ObjectQuery created with the CreateQuery method of the ObjectContext or to one which you have instantiated explicitly, as shown in the following example.

The example in the book:
var contacts = context.Contacts
.Where(c => c.FirstName == 'Roberts');

The single quotations around Roberts is incorrect. Roberts should be surrounded by double quotation marks.

I do not have much experience with Lambda expressions, but the code would not compile when Roberts is surrounded by single quotation marks. When I surrounded Roberts with double quotation marks, the application compiled and seemed to work correctly.

Please replace "United Kingdom" with "UK".

The Where clause is filtering on "United Kingdom" and should be "UK"

Note from the Author or Editor:
goes along with the same modification for example 4-9.

Missing parenthesis in the statement. Should be:

SELECT c.LastName,
ANYELEMENT(SELECT VALUE MAX(a.PostalCode)
FROM c.Addresses AS a)
FROM PEF.Contacts AS c

Note from the Author or Editor:
Please fix as noted

Third line of code snippet:

ON variable.commonproperty EQUALS variableB.commonProperty

Should mostly be:

ON variableA.commonproperty EQUALS variableB.commonProperty

syntax Group By MyTitle = Title

Should be

syntax Group By MyTitle = c.Title

if (address.CountryRegion ==

>Query projecting a single value that is an entity:
>
>SELECT VALUE c FROM PEF.Contacts AS c
>
>Each row of the DataReader that results is a DbDataRecord with one >column. The column contains an IExtendedDataRecord, which is a type >of a DbDataRecord. There is one column for every property in a >Contact entity, filled with the relevant data.

The query should goes without VALUE keyword:
SELECT c FROM PEF.Contacts AS c

Note from the Author or Editor:
Please make the change indicated above.

Please add

", which is in the System.Data namespace,"

into the first sentence of this paragraph so that it reads:

The EntityKey, which is in the System.Data namespace, is passed into the ..

Note that System.Data should be formatted similarly to the word EntityKey.

Thanks.

The page states that "You are no longer required to map all three functions and you
no longer need to provide foreign key parameters for entity references
when mapping."

In the next paragraph, the author warns about a misbehaviour concerning unmapped deletes calls when updates are mapped:
"There is a known behavior with respect to the mapping function feature.
If you map an update function but no delete function, you will get an
error when attempting to delete these entities"

According to official documentation (http://msdn.microsoft.com/en-us/library/cc716778.aspx)
"If you do not map all three of the insert, update, or delete operations of a entity type to stored procedures, the unmapped operations will fail if executed at runtime and an UpdateException is thrown."

This has proven to be true since I only mapped insert, and got EupdateException thrown on updates.

Note from the Author or Editor:
Please replace the sentence
"If you map an update function but no delete function, you will get an
error when attempting to delete these entities"

to:
"If you map some functions, but not all of them, and then attempt to execute one of the unmapped functions, you will get an UpdateException."

In NEXT sentence replace the word "both" with "all" ("does not require you to map all,)

Lodging Destinations Destination
also should be
Lodging Locations Destination

Note from the Author or Editor:
thanks

Trip Destinations Destination
Should be:
Trip Locations Destination

Note from the Author or Editor:
under the column called "Original navigation property name" please change "Destinations" on the 5th row to "Locations"

The paragraph states:

Open the project's Properties window, and on the first page, Application, change the root namespace to BAGA.

Should read somthing like:

Open the project's Properties window, and on the first page, Application, change the root namespace, VB, default namespace, C#, to BAGA.

Note from the Author or Editor:
Open the project's Properties window, and on the first page, Application, change the root namespace (VB)/default namespace (C#) to BAGA.

8.5. Mapping Stored Procedures
o UpdatePayment stored proc mapping
o Figure 8-5 does not display the 'Result Column Bindings' item for the RowVersion field

o DeletePayment stored proc mapping
o DeletePayment stored proc requires rowversion input parameter
o My solution was to remove the rowversion input parameter from the stored proc, save the stored proc, and 'Update Model from Database...' via the model's context menu

Note from the Author or Editor:
I am resending the updated image 8-5 directly to Scott Delugan at OReilly

o 8.6 Working with Many-to-Many Relationships
o The mapping identifies the EventActivities table as the target of the mapping, and then shows its ActivityID field wired up to the ActivityID field of the EventActivities table.
o the second 'EventActivities' table reference should reference the 'Activities' table.

Note from the Author or Editor:
p. 179, 2nd paragrph (starts with Instead), 2nd to last sentence ends with "field of the EventActivities table." Should be "field of the Activities table."

The second line of the VB is missing the "n" at the end of "resDateColumn":

.Columns(resDateColumn.Index) _

The VB and C# code don't match. The narrative explains that we'll be setting DataSources for activity and destination so the VB code matches the narrative but the C# code sets DataSources for customer and destination.

Note from the Author or Editor:
top of page, C# sample
first line begins with "customerBindingSource"

replace that line with :

activityBindingSource.DataSource = activities;

Up to this point the book tells us to add two class level variables, Example 8-3 page 186, modify the form load event, Example 8-4 page 186, and add the method FillCombos, Example 8-5 page 187. On the top of page 188 we are told that we can run the application again to see how the ComboBoxes have been populated. But no instruction was made to make a call to FillCombos and so the ComboBoxes are not populated. I add the following to Example 8-4 on page 186 to the end of the code snippets.

VB FillCombos()

C# Fillcombos();

Note from the Author or Editor:
At the top of page 188, please modify the paragraph that currently reads:
"Run the application again if you want to see how the ComboBoxes have been populated so far."

Add BEFORE that sentence:

Insert a call to the FillCombos method (FillCombos for VB or FillCombos(); for C#) into the form's Load event You can put this line at the end of the existing code.

Please note that all three instances of the word FillCombos should be formatted as literal text. The third instance should also include the (); in the literal formatting.

3 issues in this code snippet

1) "Now" is not valid on its own. For c# is should be "DateTime.Now".
2) Last line of code has "_adding". It should be "adding".
3) When creating the new BAGA.Contact you cannot use the default constructor (ie: new BAGA.Contact();). I am assuming you need to use the factory method (ie: BAGA.Contact.CreateContact(.....)). However if the new factory method is used it is unclear what values to pass into CreateContact for the arguments (ie: what would I put for ContactID?).

Note from the Author or Editor:
1) Change "Now" to "DateTime.Now" in the C# snippet.
2) p. 191 (VB sample) replace "_adding" with "adding"
3) p. 192 (end of VB sample) replace "_adding" with "adding"
4) p. 192 (end of C# sample) replace "_adding" with "adding"

Reader's comment #3 is incorrect. Resharper was suggesting that he replace the code with an object initializer which was confusing. The code in the book is correct.

Text says:

Note from the Author or Editor:
ecch - editing issues.

1) Please remove the entire paragraph in question: "you can return the selection lists..."

2) top of p. 197, (vb code sample 8-11 continued from p. 196)
in first line of code, replace "Dim tripResults" with "trips"

thanks.

The C# and VB code do not match

c# lstBoxTrips.Items.SortDescriptions.Add(new SortDescription("StartDate", ListSortDirection.Ascending));

should read

lstBoxTrips.Items.SortDescriptions.Add(new SortDescription("StartDate", ListSortDirection.Descending));

This code will only validate the first Trip in newTrips. The "Else Return True" in the For Each block will return if the first Trip is valid and Trip 2...n will never get tested.

Maybe something like this instead:

Function validateNewTrips() As Boolean
Dim newTrips = From t In ObservableTrips _
.Where(Function(t) t.TripId = 0)
For Each Trip In newTrips
If Trip.Lodging Is Nothing Then
Return False
ElseIf Trip.StartDate < Today Then
Return False
ElseIf Trip.EndDate < Trip.StartDate Then
Return False
End If
Next
' All must have been good
Return True
End Function

Note from the Author or Editor:
edits to VB example

remove the 11th & 12th line of the code sample that read
Else
Return True

Modify the 2nd to last line of the VB to read:
Return True 'when newTrips.Count=0 or all trips validate

In C# sample, same changes:
remove:
else
return true;

then modify 2nd to last line adding "or all trips validate" at the end

In the C# code the \\ is being used as the start of a comment line. The correct characters should be // ....

Author indicates the already instantiated object is myContact but then in the code example uses contact for the object name. The line should read:
context.AttachTo("Contacts", myContact);

Note from the Author or Editor:
yep. good catch. myContact

One thing to be sure of is that the DropDownList has "Enable AutoPostBack" checked so that the upcoming binding to a dependent DetailsView will update as expected.

Note from the Author or Editor:
On page 291, there's a numbered list of steps. Please insert this item in between the current #3 and #4 and of course, increase the numbers for the items that follow it.

4. In the DropDownList's TaskList, check the "Enable AutoPostBack" CheckBox. This will ensure the correct behavior each time the user selects an item from the list.

Thanks!

11.5. Overriding Default Code Generation
o 11.5.3.1. Inserting the Managed partial method in each entity class
o the Materialized partial method logic is not possible - the text suggests calling this partial method from the ObjectContext.ObjectMaterialized event handler; however, partial methods are implicitly marked as private. This means they cannot be called from outside the partial class.

Note from the Author or Editor:
On page 294, need to add to end of last pargraph prior to "Other wasy to create... " section.

Note that the partial method, Materialized, will be private and you cannot call it directly from the ObjectContext.ObjectMaterialized method. You'll need a wrapper method in the entity partial class, e.g., OnMateralized that is exposed and then calls the private method, Materialized.

I was building the ASP.NET application from scratch when I found that after changing the combobox at the top of web page the corresponding payment listview did not remain in synch with currently selected Contact. I tried downloading your sample code and found the same problem. It seems that after I selected the combobox multiple times the payment details that showed up in ListView was for the previous selected Contact not the currently selected one. The inital web page that is displayed does have the correct information. Additionally, if the reservation listbox is selected by manually the payment details update correctly. I am concerned that somehow the postback events are being fired before the data is actually updated thus casuing the out of synch behavior I am observing. Please confirm that you can replicate the problem I am describing and let me know if you can come up with a solution. I am looking to use Entity Framework in a similar application and want to know if there is reason for concern with this data synchronization issue. I have tried many permutations to resolve this problem (i.e., clearing listview manually, changing listbox selection to -1 and then selecting to zero if reservation exist, etc.) and have not gotten this simple example to work correctly. A little heavy on the errata but great book nonetheless!

Thanks,
Joe

Note from the Author or Editor:
noted for 2nd edition

The first sentence states:

1. Create the first association by dragging an Association control from the ToolBox and attaching one end to Customer and the other to Activity.

If you attempt to drag the Association control onto the designer your cursor will change to and O with a line through it meaning that the operation can not be done. The sentence should read something like:

1. Create the first association by selecting the Association control from the ToolBox and then positioning the cursor on the Customer entity and left click on it and then moving the cursor on to the Activity entity and click on it.

Note from the Author or Editor:
change sentence to

Create the first association by selecting the Association control from the ToolBox and positioning the cursor on the Customer entity. Click on the Customer entity, which will set the first end of the association, then click the Activity entity to set the other end of the association.

The C# code has a couple of issues.

1. This line of code is incomplete. Needs the time stamp fields to be
added for both the Contacts and Customers tables

var newCust = Customer.CreateCustomer(0, "Nola", "Claire", DateTime.Now, DateTime.Now);

Modified code:
// Initialize two TimeSpamp's for the call to CreateCustomer
byte[] contactTimestamp = new byte[] {0,0,0,0,0,0,0,0};
byte[] customerTimestamp = new byte[] {0,0,0,0,0,0,0,0};

var newCust = Customer.CreateCustomer(0, "Nola", "Claire", DateTime.Now, DateTime.Now,
contactTimestamp, customerTimestamp);

2. The following error is thrown when SaveChanges is executed and the following statement is not added.

Entities in 'BAEntities.Contacts' participate in the 'FK_Customers_CustomerTypes'
relationship. 0 related 'CustomerTypes' were found. 1 'CustomerTypes' is expected.

Added the following line of code which adds a CustomerType "Silver" to the new Customer:
newCust.CustomerType = context.CustomerTypes
.Where(ct => ct.CustomerTypeName == "Silver").Select(ct => ct).First();

3. The following query:
// Query for a Customer and modify a new property
var firstCust = (from c in context.Contacts.OfType<Customer>()
select c).FirstOrDefault();

Returns a record whos BirthDate field is already set to 1/24/1981 so the following line should not cause the DB to be updated because you are modifying the field with the same value therefore no change.

firstCust.BirthDate = new DateTime(1981, 1, 24);

Note from the Author or Editor:
#1 is correct, please implement it
#2 is wrong - do not implement the proposed change. That setting is performed in SavingChanges
#3 change that line of code so that it is (1981,1, 26)

This is from the 2nd Edition. A step is missing from the instructions; the missing step is enclosed here in angle brackets:

"...comment out the call to DetectChanges that you added earlier," <replace the statement firstContact.Addresses.Add(newAddress) with firstContact.AddAddress(newAddress),> "and run the application again."

The example still works if you leave the call to Contact.Addresses.Add in place (because of the check for Contains), but does not work without the call to Contact.AddAddress

Note from the Author or Editor:
thanks

Printed "The BreakAway database has a stored procedure called CreateCustomerfromClient".
Actual stored procedure's name is CreateCustomerfromContact.
In paragraph 4 was used the same erroneous reference.

Note from the Author or Editor:
Be sure to change both instances of this. Thanks!

In the instructions for creating the new 'NonCustomer' derived type, Step 1 notes "You can create a new entity by right-clicking the design window and selecting Add and then Entity, or by dragging an Entity from the Toolbox."

The subsequent steps assume you use the former method (the context menu). If you click-drag a new entity into the model, Visual Studio will automatically add an "Id" property to it. If you follow the rest of the steps and try to run the project, you will get mapping errors at runtime because the Id field is not mapped. In this case you must delete the "Id" property from the new entity.

Note from the Author or Editor:
thanks

The entries in difference column for lines 2, 4 and 5 are incorrect:
If 108 ms is 8% difference, then 320 ms, 412 ms and 207 ms difference are 320%, 412% and 207% difference respectivly.

Note from the Author or Editor:
please remove the difference from base column completely

In the VB sample, please move the line "End Using" so that it is just above the line "End Function". This will impact the tabbing. It should look like this:

Public Function GetTrips() As List(Of BAGA.DTO.Trip) _
Implements ICustomerService.GetTrips
Using listProvider As New BAGA.Providers.ListProvider
Dim tripsList = CType(ListProvider.GetReferenceList(Of Trip)(""), _
List(Of Trip))
Dim trips = From t In tripsList _
Select New BAGA.DTO.Trip With _
{.TripID = t.TripID, .TripDetails = t.TripDetails}
Return trips.ToList
End Using
End Function

In the C# sample, we need to move the first closing brace down so that it is just above the 2nd closing brace. Tabs affected here too.

public List<BAGA.DTO.Trip> GetTripsDTO()
{
using (var listProvider=new BAGA.Providers.ListProvider())
{
List<Trip> tripsList = (List<Trip>)listProvider.GetReferenceList<Trip>("");

var trips =
from t in tripsList
select new BAGA.DTO.Trip
{TripID = t.TripID, TripDetails = t.TripDetails};
return trips.ToList();
}
}

Note from the Author or Editor:
It looks like my attempt to show how to format the tabbing got wiped out by the submittal form. Please check with me when it's time to make this fix and I can show you what it should look like.

Please remove the line "add.TimeStamp=originalTS" that is just above "Next". This was accidentally left over when modifying the book's text to match refactored code.

More problems caused by updating the book's text after refactoring the code sample.

1)
Please change the line JUST ABOVE "Step 4" so that it says
"If custEF.EntityState_Local" instead of "If cust.EntityState_Local"

2)
Line just above "Step 2" should be:
"Using context = New BAEntities"
instead of "Using context = New BreakAwayEntities"

place curly braces before and after the first line which is a comment.

SHould look like:

{
//we're not deleting customers
}

Note that there should be two paces in front of the middle line.

replacing RemoveChild method in C# sample

Here is the new C# version:

This form will mess up indentation, so please note:
2 spaces in front of third line. -->if (childEntity...
4 spaces in front of 4th line -->((Address)childEntity...
2 spaces in front of 5th line ---> if(childEntity...)
4 spaces in front of 6th line -->((Reservation)childEntity...

public void RemoveChild(object childEntity)
{
if (childEntity is Address)
((Address)childEntity).EntityState_Local = EntityStateLocal.Deleted;
if (childEntity is Reservation)
((Reservation)childEntity).EntityState_Local = EntityStateLocal.Deleted;
}

2nd line from the bottom should be
var add = cust.Addresses[i];


(replacing parens with square brackets)

Issues with last minute changes to text of C# code sample. (Readers can download the correct code sample from learnentityframework.com/downloads).

Starting with where the C# example begins in the middle of the page.

4th line should end with: GetCustomerList(); <--adding parens
5th line should end with: GetTripList(); <--adding parens
9th line: [randomPositioninList] <--replacing parens with square brackets
13th line: DateTime.Now.ToShortDateString(); <--adding "DateTime."

18: [cust.Reservation.Count-1]; <--replacing parens with square brackets
20 cust.RemoveChild(reslast); <--reslast replaces lengthy parameter

On page 749 where sample continues
5th line from top: Reservation[i]; <--replacing parens with square brackets

EDITOR: Please contact me (author) with any questions!

Note from the Author or Editor:
the note about p. 749 is accurate, I got my papers shuffled around. It's just part of a different sample.

4th code line down, modifying code line and then adding another line of code below it.

var trip = triplist[randomPositioninList];
res.TripID = trip.TripID;


10th line down
var add = cust.Addresses[0]; <--replacing parens with square brackets