Setting updateSchema="false" in the configuration section of the XML file for the SQL producer will prevent Codefluent from altering the schema (i.e. field names, field type, indexes, etc) of the SQL table while still allowing for the creating of stored procedures and methods against the table. This is discussed in the blog article https://blog.codefluententities.com/2011/10/31/interoperate-with-an-existing-database-using-codefluent-entities/
Question
Is there anything built in that would achieve the same effect but apply only apply to the underlying tables of specific entities?
You can disable table diffs generation for a specific entity using an attribute:
<cf:entity name="Customer" cfps:produceTableDiff="false">
<cf:property name="Id" key="true" />
</cf:entity>
Related
I'm maintaining an asp.Net MVC 3 web application using Entity Framework 4.1 Database first approach. I have had to add two new properties to one of the tables in the database.
I then right clicked on the EDMX diagram and choose 'Update Model from Database' within the context menu, like so:
This works without any problems, but the two new fields aren't added to the expected table. However, when I open the EDMX file in XML format, I can see the two new fields listed, like so:
<EntityType Name="Shift">
<Key>
<PropertyRef Name="shiftID" />
</Key>
<Property Name="shiftID" Type="int" Nullable="false" StoreGeneratedPattern="Identity" />
//Two new fields below
<Property Name="shiftTitleGradeID" Type="int" />
<Property Name="shiftTitleSubID" Type="int" />
</EntityType>
Can anyone advise me on how to get the two new fields into my EDMX diagram and not just the XML file?
Thanks in advance.
Got it fixed. I had to delete all references to the new properties in the XML file. Then recreate the update model from database procedure, this time ensuring the two checkboxes where ticked, Pluralize or singularize generated object names, and, Include foreign key columns in the model (I thought I had these ticked the first time, but I didn't).
This fixed my problem.
Well tested running system have already defined entity called 'User'.
Now I need to add a new property to User entity (ex: Age)
To do this in the safe way, I do not like to do any changes with the existing data base table, because that is very risky in my case. I need a way to rebuild the User entity with the minimum code changes.
So my proposal is:
Create a new table (user_age), with two columns (user_id, age)
Modify the user entity to add property 'age' and its getter-setters
So my entity (User) properties, will be saved to two different tables (user and user_age)
Loading the user is also similarly.
Is this possible to do with hibernate....??
If not, Any other safer way to do this with Hibernate...?
what are the available ORMs that provide this kind of feature (nhibernate, entityframwork,etc... or any other ORM)...?
Yes, there are various approaches:
[1] See JPA Secondary Tables. This allows you to map an Entity to two or more tables.
Section 2.2.7: http://docs.jboss.org/hibernate/annotations/3.5/reference/en/html_single/#d0e2235
[2] Create another Entity, say UserInfo, mapped to this new table. Create a one-to-one mapping from User to UserInfo.
Yes. You can do that.
I've used for a similar problem a joined-subclass.
Base:
<class name="User" table="Users">
<id name="Code" type="System.Guid">
<column name="Code" />
<generator class="guid.comb" />
</id>
...
</class>
Subclass:
<joined-subclass name="UserExt" extends=User" table="UsersExt">
<key column="Code" />
<property name="Age">
<column name="Age" not-null="true" />
</property>
</joined-subclass>
A good reference here.
NHibernate's join mapping is for exactly this case.
See Ayende's blog and the documentation for more information. From the documentation:
Using the <join> element, it is possible to map properties of one class to several tables, when there's a 1-to-1 relationship between the tables.
From my searches, it looks like it is also possible to do this with Entity Framework: Simon J Ince - Mapping two Tables to one Entity in the Entity Framework . I think this article is about Entity Framework v1, and things could have changed by now, but it appears that there is an important limitation in Entity Framework's version of this mapping:
... it requires a record in each table to exist as the generated SQL uses an INNER JOIN. It makes sense if you're using a new model, but I guess this is more tricky if you're mapping to an existing schema and data.
With NHibernate, you can set the optional attribute on the join mapping to tell it to use outer joins instead of inner joins.
optional (optional - defaults to false): If enabled, NHibernate will insert a row only if the properties defined by this join are non-null and will always use an outer join to retrieve the properties.
I have a View which looks similar to this:
SELECT Id, Name
FROM Users
UNION ALL
SELECT NULL as [Id], NULL as [Name]
When I try to map to this view in Entity Framework, it just fails. I don't get an error, but the view does not exist in my data store. Why is this? Is there a way around it?
I know this is an older question already marked as answered, but I wanted to post an alternative to editing the edmx. I learned this one the hard way, after tons of Google searches and pulling my hair out for hours, trying different options...
For a view, EF attempts to to infer a primary key by identifying columns that are non-nullable
and non-binary (see Create an Entity Key When No Key Is Inferred).
With a view used to flatten related data for lookup purposes, this can result in many columns (or the wrong ones) being inferred as keys.
For a view with a UNION, it can cause the opposite problem, because there may be no true identity column that can be safely included as a key.
To force EF to identify columns as a key, you can use ISNULL() to ensure the value is non-nullable: ISNULL(column_name, replacement_value)
To force EF to not mark a column as a key, you can use NULLIF() to make it nullable: NULLIF(column_name, value_not_equal_to_parameter_1)
If you need to ensure a value is returned, but don't want to have it marked as a key, I believe COALESCE(column_name, replacement_value) will do the job of ISNULL without EF marking the column as a key
If there is truly no viable column available as a primary key (as in a UNION view), you can fake a non-nullable PK through the use of ISNULL() combined with ROW_NUMBER() in your SELECT statement: SELECT ISNULL(ROW_NUMBER() OVER (ORDER BY sort_criteria), 0) as 'ALIASNAME'
As an alternative, the edmx can absolutely be edited directly as Marcos Prieto suggested, but you run the risk of having those changes overwritten the next time you run "Update Model from Database".
Hope this helps anyone who encounters this in the future!
It is because Visual Studio cannot infers the Primary Key of your View.
You can see the error message within edmx file by open it with XML editor and see the SSDL section.
Here is error message that results from my Model(which I created some View like yours within my Database just to emulate) :
Errors Found During Generation:
warning 6013: The table/view 'PhoneBook.dbo.ContactCustomer' does not have
a primary key defined and no valid primary key could be inferred.
This table/view has been excluded. To use the entity,
you will need to review your schema,
add the correct keys, and uncomment it.
It is not true that Union is not supported in EF 4.
But I think the problem is that Visual Studio saw your view as the odd View.
You can doing some experiment by create another View and compares them (using update model from database menu within model designer).
And you can modify the Model by hand (manual typing the edmx file) to define the Primary Key to resolve this.
I had a view that worked perfectly. I modified it (changed the view on a union of 2 tables), updated the model from database and this problem appeared.
I fixed it in 3 steps:
Open the .edmx file with a XML editor.
Uncomment the view's EntityType XML (edmx:StorageModels > Schema) code and add the Key:
<EntityType Name="your_view">
<Key>
<PropertyRef Name="your_id" />
</Key>
<Property Name="your_id" Type="int" Nullable="false" />
<Property Name="other_field" Type="varchar" MaxLength="45" />
</EntityType>
Be sure that EF didn't erased the view in edmx:StorageModels > Schema > EntityContainer (if you have code repository, copy the code from there):
<EntitySet Name="your_view" EntityType="Your_Model.Store.your_view" store:Type="Views" store:Schema="your_schema" store:Name="your_view">
<DefiningQuery>SELECT
`your_view`.`your_id`,
`your_view`.`other_field`,
FROM `your_view` AS `your_view`
</DefiningQuery>
</EntitySet>
I know this is an old question but i faced this issue recently & after trying to do the above mentioned methods i simply created another view that selects from the Union view & i was able to map the new view by updating my entity model.
Using the Entity Framework, I've modeled a fairly simple database schema with an ever-so-slightly more complex class hierarchy. In two places, I'm using single table inheritance with a single NVARCHAR(20) NOT NULL discriminator column. In one of those two places, it works great, no issues. But in the other place, with an almost identical pattern, I get the following error:
Error 3023: Problem in Mapping Fragments starting at lines 371, 375, 379, 382: Column MediaStream.MediaStreamTypeID has no default value and is not nullable. A column value is required to store entity data.
An Entity with Key (PK) will not round-trip when:
((PK does NOT play Role 'MediaStream' in AssociationSet 'FK_MediaStream_SessionID' OR PK is NOT in 'MediaStream' EntitySet OR Entity is type [SlideLinc.Model].MediaStream) AND (PK plays Role 'MediaStream' in AssociationSet 'FK_MediaStream_SessionID' OR PK is NOT in 'MediaStream' EntitySet OR Entity is type [SlideLinc.Model].MediaStream) AND (PK plays Role 'MediaStream' in AssociationSet 'FK_MediaStream_SessionID' OR PK is in 'MediaStream' EntitySet))
Here's the table definition (not including various indexes, foreign keys, etc.):
CREATE TABLE [dbo].MediaStream(
[MediaStreamID] UNIQUEIDENTIFIER NOT NULL,
[SessionID] UNIQUEIDENTIFIER NOT NULL,
[RtmpUri] nvarchar(250) NOT NULL,
[MediaStreamTypeID] nvarchar(20) NOT NULL,
CONSTRAINT PK_MediaStream PRIMARY KEY CLUSTERED
(
[MediaStreamID] ASC
)
I'm using the MediaStreamtypeID column as the discriminator: if it's set to "video", a VideoMediaStream class should be created, and if it's set to "audio", an AudioMediaStream class should be created.
The relevant portions of the EDMX file look like this:
<EntitySetMapping Name="MediaStream">
<EntityTypeMapping TypeName="IsTypeOf(SlideLinc.Model.MediaStream)">
<MappingFragment StoreEntitySet="MediaStream">
<ScalarProperty Name="RtmpUri" ColumnName="RtmpUri" />
<ScalarProperty Name="MediaStreamID" ColumnName="MediaStreamID" /></MappingFragment></EntityTypeMapping>
<EntityTypeMapping TypeName="IsTypeOf(SlideLinc.Model.VideoMediaStream)">
<MappingFragment StoreEntitySet="MediaStream" >
<ScalarProperty Name="MediaStreamID" ColumnName="MediaStreamID" />
<Condition ColumnName="MediaStreamTypeID" Value="video" /></MappingFragment></EntityTypeMapping>
<EntityTypeMapping TypeName="IsTypeOf(SlideLinc.Model.AudioMediaStream)">
<MappingFragment StoreEntitySet="MediaStream" >
<ScalarProperty Name="MediaStreamID" ColumnName="MediaStreamID" />
<Condition ColumnName="MediaStreamTypeID" Value="audio" /></MappingFragment></EntityTypeMapping></EntitySetMapping>
<AssociationSetMapping Name="FK_MediaStream_SessionID" TypeName="SlideLinc.Model.FK_MediaStream_SessionID" StoreEntitySet="MediaStream">
<EndProperty Name="MediaStream">
<ScalarProperty Name="MediaStreamID" ColumnName="MediaStreamID" /></EndProperty>
<EndProperty Name="Session">
<ScalarProperty Name="SessionID" ColumnName="SessionID" /></EndProperty></AssociationSetMapping>
So there are multiple things about this error that I don't get:
(1) Why does exactly this same approach work for my other class hierarchy, but not this one? I thought it might be the Entity Designer getting confused, so I deleted this portion of my hierarchy (in the XML), and recreated it, but I'm still getting it. I could try recreating the whole damn thing, but hell, that's a lot of work, and if I'm gonna have to be doing this very often, that doesn't leave a great taste in my mouth about the entity framework.
(2) What is it complaining about in the first place? I don't get how MediaStreamTypeID (which isn't a member of the primary key) has anything to do with the primary key at all, or why the fact that it can't be null is a problem (especially given that this same setup works elsewhere in my model!).
Any thoughts or suggestions?
I had a similar problem, and was able to solve it by setting the "Abstract" property for the base class to "True" and by removing the discriminator column from the base class in the model (either in the *.edmx file or in the designer view within Visual Studio).
I got the exactly same error but maybe with different reason from yours.
In the code below, I mis-copied some codes so 2 of inherited classes (LeveledItem and Team) are of the same "Type".
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
Database.SetInitializer(new ScrumDbContextInitializer());
base.OnModelCreating(modelBuilder);
modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
modelBuilder.Entity<LeveledItem>()
.Map<LeveledItem>(m => m.Requires("Type").HasValue(typeof(LeveledItem).Name))
.Map<Team>(m => m.Requires("Type").HasValue(typeof(LeveledItem).Name))
.Map<Story>(m => m.Requires("Type").HasValue(typeof(Story).Name))
.Map<Task>(m => m.Requires("Type").HasValue(typeof(Task).Name)) .Map<Sprint>(m => m.Requires("Type").HasValue(typeof(Sprint).Name));
After the second one was changed to "typof(Team).Name", the error was fixed.
I had a similar problem to this, just out of interest, does deleting the .EDMX file and recreating it from scratch solve your problem?
What caused the problem:
Created a set of tables with some 0..* mappings
Generated the Entity Framework class, customised a whole bunch of Navigation properties
Went back to the DB and changed the cardinality of some of the 0..* to 1..* relationships - ie: set some of the FKs to !nullable
Updated the Entity Framework
Recompiled and BOOM I got a compilation error similar to yours
There seems to be an issue where the "Update Model from Database" command doesn't update the changed relationships correctly.
The solution was to open the EDMX file, look for the <Association Name="FK_XXX_XXX"> elements that were generated the first time and change the Multiplicity attribute on the relevant End point from Multiplicity="0..1" to Multiplicity="1"
I encountered this error when I inadvertently mapped 2 classes to the same table via the [Table] attribute (same effect via modelBuilder ToTable())
See images:
EF Designer
SQL Tables
"Two entities with different keys are mapped to the same row. Ensure these two mapping fragments do not map two groups of entities with overlapping keys to the same group of rows."
In fact, only one of the two (or 6 here) entities will have the key for the single row.
How may I overcome this? SQL View that combines them all to one row? Calculated discriminator column in ContactMethod? How should I have designed the tables differently to work better with EF?
Or is there some XML editing I can do to keep my schema and just tell EF to trust me that I'd never put the same Id in more than one derrived class?
Here's: edmx if it helps.
The link to edmx file is not work. Perhaps, you have to add a condition tag
<Condition ColumnName="ContactId" IsNull="false" />
to your edmx file using xml-editor:
<AssociationSetMapping Name="FK_Contact_ContactMethod" TypeName="SomeNamespace.FK_Contact_ContactMethod" StoreEntitySet="ContactMethod">
<EndProperty Name="ContactMethod">
<ScalarProperty Name="ContactMethodId" ColumnName="ContactMethodId" />
</EndProperty>
<EndProperty Name="Contact">
<ScalarProperty Name="ContactId" ColumnName="ContactId" />
</EndProperty>
<Condition ColumnName="ContactId" IsNull="false" />
</AssociationSetMapping>
Taking off the foreign keys to ContactMethod in the database got rid of the errors, but doesn't seem right.