I have a logger added that store logs when an entity is saved. What I am trying to get is how would I determine which fields have been edited for instance if I have 5 columns in one entity and I change only two columns so I would like to get the difference of only those two columns as they have been edited.
Something like $entity->change() so it would provide me old and new values of those two columns. I am trying to find out in zend but sadly haven't progressed any further.
Related
I have two entities: product and category (Symfony 2.3).
I want to create a form in which an user can choose a product by first selecting the category. A user selects the category by clicking on image, then I want to set the image's value into a hidden input, but I don't see how can I change a foreign entity choice list to a hidden input (http://symfony.com/doc/current/reference/forms/types/entity.html).
How can I accomplish this? (how to change form input to hidden)
If I set cascade validation to true, will it for example check if a category really exist. (To prevent putting products with non-existing category from malicious users) ?
Part 1
To do this you need to use a data transformer to do two things:
transform an entity into an identifier that is either a string or integer so a form can render it as a hidden field.
transform the string or integer identifier into the entity when the form is submitted so that the parent entity can be saved with the correct relationship
The symfony docs I linked to above (here too) actually walk though an entire example of using a data transformer with a form.
As a shameless plug (because I believe it is helpful) I have written a little tutorial on using a data transformer for a hidden field with an entity id: http://lrotherfield.com/blog/symfony2-forms-entity-as-hidden-field/
Part 2
If you are using the data transformer then you don't need to worry about malicious users. The data transformer will fail because it will not be able to reverse transform the category from the fake id. In my tutorial the transformer will throw a Symfony\Component\Form\Exception\TransformationFailedException exception.
You can also write a validator (potentially using a call back) if you wanted that checks that the submitted category is real if you want an error to show in the form. Doctrine wont allow you to persist a fake category relationship as the foreign key constraint will fail.
I'm really new to Entity Framework (currently using EF5) and vs2012 and am having difficulty trying to figure something out.
I have an .edmx that was generated from my database. It has two tables in it: Item and 3rdPartyItem. In short, the Item table is the main table for all the company items while the 3rdPartyItem table is a table that is used to hold additional attributes for items. This 3rdPartyItem table was created by an outside company and is used with their software for the company, so I can't mess with either table. What I'm trying to do is show a list of Items in a grid but I need to show a combination of all the fields for both tables. In vs2012, if I create a relationship and make it 'zero-to-one' (because for each record in the Item table, there doesn't necessarily have to be one in the 3rdPartyItem table), vs complains about not being mapped correctly. When I set the mapping, it then complains that there's multiple relationships. I did some research and found that you can't create a relationship with 2 primary keys, so I was thinking that was the problem. But how can I change the .edmx so that in code, I can access Items and 3rdPartyItem like so:
var items = dbContext.Items;
items.3rdPartyItem.SomeField <--field from 3rdPartyItem table.
not too sure if it's even possible, but it would be very, very helpful if so. Any ideas?
What you're looking for is table-per-type (TPT) mapping inheritance. You can view an MSDN walkthrough here (although you'd want your base type to be instantiable):
http://msdn.microsoft.com/en-us/data/jj618293.aspx
None of the many questions on this topic seem to match my situation. I have a large data model. In certain cases, only a few of the fields need be displayed on the UI, so for those I replaced the LINQ to Entity query that pulls in everything with an Entity SQL query retrieving only the columns needed, using a Type constructor so that I got an entity returned and not a DbDataRecord, like this:
SELECT VALUE MyModelNameSpace.INCIDENT(incident.FieldA, incident.FieldB, ...) FROM ... AS ...
This works and displays the fields in the UI. And if I make a change, the change makes it back to the entity model when I tab out of the UI element. But when I do a SaveChanges, the changes do not get persisted to the database. No errors show up in the Log. Now if I very carefully replace the above query with an Entity Sql query that retrieves the entire entity, like this:
SELECT VALUE incident FROM MyDB.INCIDENTs AS incident...
Changes do get persisted in the database! So as a test, I created another query like the first that named every column in the entity, which should be the exact equivalent of the second Entity SQL query. Yet it did not persist changes to the database either.
I've tried setting the MergeOption on the returned result to PreserveChanges, to start tracking, like this:
incidents.MergeOption = MergeOption.PreserveChanges;
But that has no effect. But really, if retrieving the entire entity with Entity Sql persists changes, what logical purpose would there be for behaving differently when a subset of the fields are retrieved? I'm wondering if this is a bug?
Gert was correct, the problem was that the entity was not attached. Dank U wel, Gert! Ik was ervan verbluft!
I just wanted to add a little detail to show the full solution. Basically, the ObjectContext has an Attach method, so you'd think that would be it. However, when your Entity SQL select statement names columns, and you create the object using a Type as I did, the EntityKey is not created, and ObjectContext.Attach fails. After trying and failing to insert the EntityKey I created myself, I stumbled across ObjectSet.Attach, added in Entity Framework 4. Instead of failing, it creates the EntityKey if it is missing. Nice touch.
The code was (this can probably be done in fewer steps, but I know this works):
var QueryString = "SELECT VALUE RunTimeUIDesigner.INCIDENT (incident.INCIDENT_NBR,incident.LOCATION,etc"
ObjectQuery<INCIDENT> incidents = orbcadDB.CreateQuery<INCIDENT>(QueryString);
incidents.MergeOption = MergeOption.PreserveChanges;
List<INCIDENT> retrievedIncidents = incidents.ToList<INCIDENT>();
orbcadDB.INCIDENTs.Attach(retrievedIncidents[0]);
iNCIDENTsViewSource.Source = retrievedIncidents;
Problem: When adding an object "Order" to my dbcontext, all nested objects of the order gets "readded" to the database, though the nested objects is static data and only a reference shoudl be added in the database.
Example:
The database holds 0 orders, and 3 items.
I add one order with 2 items.
Now the database hold 1 order, and 5 items. The two items in the order has been "readded" to the database, even though the items had the right primary keys before db.SaveChanges().
I realize that i may be able to attach the existing items to the dbcontext before saving changes, but is that really the only way to go? Can't EF figure out that to item already exists when the primary key matches an existing item?
Does anyone know if this is different in the new version of EF CodeFirst?
No EF cannot figure if entities are existing one or new one - both Add and Attach commands are graph oriented operations. You call them on one entity in the graph and they traverse all relations (and their relations and so on) and perform the operation for them as well.
You must figure correct state of each entity in the graph for example by using:
dbContext.Orders.Add(newOrder);
foreach(var item in newOrder.Items) {
dbContext.Entry(item).State = EntityState.Unchanged;
}
dbContext.SaveChanges();
You can use the reverse operation by calling Attach(newOrder) and set the order to Added state. The main difference will come with independent associations (for example many-to-many relations). The first approach will correctly add new relation between order and each item whereas second will not unless you manually set each relation to Added state (and changing state for relations is more complex).
I'm new to EF, and trying to work out the best way to do something
I have a procedure that returns the details of a table, but also a calculated value. What I'd like is for it to return this information to an entity that could contain this, whether it's the original entity, or an entity that's based on the original (so that if the original table changes, it will still map). What I'd like to avoid is maintaining 2 entities - 1 for the table, and 1 for the stored procedure results.
Thanks...
You could create a view that contained the table fields as well as the calculated values.