I am working on a MVC3 code first web application and after I showed the first version to my bosses, they suggested they will need a 'spare' (spare like in something that's not yet defined and we will use it just in case we will need it) attribute in the Employee model.
My intention is to find a way to give them the ability to add as many attributes to the models as they will need. Obviously I don't want them to get their hands on the code and modify it, then deploy it again (I know I didn't mention about the database, that will be another problem). I want a solution that has the ability to add new attributes 'on the fly'.
Do any of you had similar requests and if you had what solution did you find/implement?
I haven't had such a request, but I can imagine a way to get what you want.
I assume you use the Entity Framework, because of your tag.
Let's say we have a class Employee that we want to be extendable. We can give this class a dictionary of strings where the key-type is string, too. Then you can easily add more properties to every employee.
For saving this structure to the database you would need two tables. One that holds the employees and one that holds the properties. Where the properties-table has a foreign-key targeting the employee-table.
Or as suggested in this Q&A (EF Code First - Map Dictionary or custom type as an nvarchar): you can save the contents of the dictionary as XML in one column of the employee table.
This is only one suggestion and it would be nice to know how you solved this.
Related
I'm currently developing my first MVC component for Joomla 3.x. All in all I'm bit struggling with language/translation issues in database.
My problem is that I need to store translated content of user generated content which comes from the backend. For example someone enters a new item in German (stored in database) and needs a translation in another language. How to accomplish that in Joomla? I don't like to generate a new item for every different language when the rest is all the same.
I thought about a table "item" and a table "item_language" with that structure (strongly simplified for viewing purposes):
item
id PRIMARY INT
price DOUBLE(4,2)
item_language
itemid PRIMARY INT
language PRIMARY CHAR(5)
name VARCHAR(50)
In item_language I would like to store the different translated versions. In the language field there would be the region code (eg. de-DE) to identify the language.
My problems:
How to display the different (translated) versions in backend?
Is this the right database model?
Any help is appreciated!
You have really found yourself a nice task for a first component in Joomla!
A rather generalist answer:
The database model seems right. Alternatively you could encode in JSON the language data, but this could make later query operations potentially difficult. This way you will only have one table to work with.
As far as I know (if you are using JModel / JTable to manipulate the data) can't do this directly, as JTable is really only designed to manipulate single tables.
What you can do:
For editing: figure a way to represent this graphically ( for your users to see and edit this one to many relationship) and to post this data (language texts as an array) to JModel. In the model you can maintain the desired relationships and save the data using JTable.
Viewing (without editing) shouldn't be an issue, it would be a simple JOIN.
If you are willing to create a basic component on github, I might even give you a hand with JModel / JTable.
I found a way to deal with the things I needed.
Thanks Valentin Despa for guiding me in the right direction :-).
Here the whole procedure (simplified - validations and exact steps omitted):
Define the form fields in the models/forms/site.xml as normal.
In views/site/tmpl/edit.php add self coded Javascript (based on jQuery) to deal with the fields which have content in multiple languages stored as JSON in database.
Clone the original form element and modify the needed attributes (id, name, ...) to display a special version just for the defined languages. As content - extract the JSON for the needed language from original field content and display.
Hide the original field with Javascript and append the customized versions to DOM.
Afterwards in tables/site.php I read the dynamically generated content withJInput and build together the original field by generating JSON and saving to database.
It's working like expected.
I have a working system that lets me build a database containing instances of various entities , all linked together nicely.
Before I knew I would care, I came across a tutorial on using Core Data and bindings, and it went through a complete case where you get a table showing all the entities of some type with a column for each property. It showed both the UI side and the Data model side - not that I need the data model part at this point. Now, darned if I can find it. This is one of those things that is supposed to be easy, and requires virtually no code, but getting exactly the right connections in UIBuilder is not going to happen if I can't find instructions.
Also, I thought I came across an example of something like a query editor where the user could select which properties to sort on, which to match on, etc. Did I imagine that?
Anyone out there know where I can find such?
Sure, you can do this without code:
Add an array controller to your nib.
Bind or connect an outlet for its managed object context
Set the array controller to Entity mode, fill in the entity name, and select Prepares Content.
Bind your table view columns to array controller's arranged objects, and fill in the key name for the model key.
Regarding the query editor, open up the model, and on the Editor menu click Add Fetch Request.
I found at least a partial answer to the query editor question, in this apple tutorial. Not sure how far it will get me, as I prefer to write code where possible, since then I can leave a trail of comments.
I have a populated object from using the entity framework. Let's call it Order. The order has different properties such as Id, OrderDate, BillingAddress and so on. I need to let users update this data.
What's the best way to display this data in a form, while enforcing data annotations such as [Required]? I see MetadataType mentioned a lot, but I haven't seen how I can connect the dots with displaying the data as well.
One approach that I could take, but I'd like to avoid because of redundancy, is creating my own model object that has nearly identical properties. Then I would just need to basically just copy entity framework object A to new object B, where B has all my lovely data annotations. It just seems like there might be a better way.
Could anyone provide me with an example of a good way to accomplish this?
The "better way" is a big reason EF Code First is great. Otherwise, the only other way to do what you need is to do a mapping.
I got a silly general question...
If I generate a strongly typed view of an entity and chose "edit" as scaffolding, then the view does contain every column for that table. Changing and saving the values via setting it modifierd and call db.SaveChanges() does work in the controller. So far, so good.
But if I remove just one of that columns inside the view, then saving doesn't work anymore.
Is there a rule describing this? Is it only possible to make view with every column when wanting to save the model later on? I don't want to make 90 of 100 columns "hidden"...
PS: When editing a value in another table which is connected via Foreign Key (like customer.address.STREET) saving also does not work. Does everything of the entity ADDRESS has to be inside the view? I really don't get that.
Besides that: If I create my own ViewModel containing two entities: Do they also have to hold every column of both entities? This would be a whole bunch of traffic...
Answer is: You should not use the .Modified state. Instead using the UpdateModel method works fine without every field.
I've made a custom entity that will work as an data modification audit (any entity modified will trigger creating an instance of this entity). So far I have the plugin working fine (tracking old and new versions of properties changed).
I'd like to also keep track of what entity this is related to. At first I added a N:1 from DataHistory to Task (eg.) and I can indeed link back to the original task (via a "new_tasksid" attribute I added to DataHistory).
The problem is every entity I want to log will need a separate attribute id (and an additional entry in the form!)
Looking at how phone, task, etc utilize a "regardingobjectid", this is what I should do. Unfortunately, when I try to add a "dataobjectid" and map it to eg Task and PhoneCall, it complains (on the second save), that the reference needs to be unique. How does the CRM get around this and can I emulate it?
You could create your generic "dataobjectid" field, but make it a text field and store the guid of the object there. You would lose the native grids for looking at the audit records, and you wouldn't be able to join these entities through advanced find, fetch or query expressions, but if that's not important, then you can whip up an ASPX page that displays the audit logs for that record in whatever format you choose and avoid making new relationships for every entity you want to audit.
CRM has a special lookup type that can lookup to many entity types. That functionality isn't available to us customizers, unfortunately. Your best bet is to add each relationship that could be regarding and hide the lookups that aren't in use for this particular entity.