If I create an entity data model using the using the model first approach and building my model from an existing database is there a way that I could then automate the creation of partial classes to then allow me to extend the model to fit my requirements. So for example were I to model the Northwind Database then, amongst others, entities would be created for 'Customer' and 'Order'. I would like to find a way to then have visual studio to build a set of partial classes for each of the entities and put them into separate files.
I have no idea if this is doable in the first place, or if it is what the best way to go about doing it would be. To that end I would welcome any suggestions and / or good basic examples of where to start learning how do to this sort of thing. Ideally any such examples would have content in vb as well as c#.
Many thanks
Related
I have a dataset table with various columns that are created during form load.
These columns are currently either system.double or system.string types.
And it is displayed in a datagridview.
This works fine.
But I need another column that can store a "list" or some collection in the data table.
A list of strings would do but a custom class would be better.
How is this usually done?
I have spent literally weeks googling this and I dont know where to start. The more I have looked the more confused I have ended up. I end up with more questions than answers, like how is it displayed in the datagridview? I read about a combo box?
I hope someone can give me some pointers in how to get this achieved. I've not posted any code as I think its more the theory of this I need help with.
What you are asking for has does have multiple concerns for most programmers. The storage of data (#1) and the displaying of said data to the user (#2)
For #1 I recommend the .net entity framework. It gives support for storing, querying and updating classes for use in the database. Through most tutorials that I have found it is possible to model the structure of the database tables and their relations and then build a database around that model OR to use an existing database and create entities (entity framework's class objects) around the existing structures and relationships.
Here is a link to a very good beginner tutorial that I have used before: CodeProject Entity Framework Tutorial for Absolute Beginners
For #2 I can recommend the Windows Presentation Foundation. It has lots of bells and whistles to make using a data source and displaying the relevant dependent data very easily through its unique method of data binding. From the tutorials I have used on PluralSight it can be as easy as dragging and dropping from an imported data source like the entity framework database. Alternatively, one can just handle selected row changes for one data grid and then show the dependent data in another data grid.
My team is writing a large scale business website in ASP.NET MVC 4 using the database-first approach. Does anyone know if it's possible to have data annotations automatically generated based on the database schema? It seems redundant to have to manually write the "buddy" metadata classes containing the data annotations when the framework should be aware of a database column's properties and make these part of the POCO classes it generates. Any suggestions would be greatly appreciated!
Take a look at LINQ to SQL.
You can use it to create a .dbml file in a graphical editor by dragging the tables from the server explorer.
Here's the MSDN How to: Create LINQ to SQL Classes in a Web Project
1) The framework does a good job of extrapolating data annotation based on table structure, but they won't be perfect.
2) Sadly, when you reach a point when you want to customize more than the framework, you are stuck with Buddy classes. They're a bit tedious but so far the best method I've found for customizing data annotation.
3) All too often, I find myself gravitating toward custom classes and away from generated POCO's. The reason is usually the differences between storing and displaying. In entry screens
I will often break up phone #'s into 3 textboxes.
Lookups for foreign keys require select lists (often added to model).
Often I'll pass other values that may be relevant to my View functionality but not specific to the storage table (display fields, navigation / bread crumbs)
Use the Database First approach with the Entity Framework.
You can generate the entity model from an existing database using the entity data model wizard.
See http://msdn.microsoft.com/en-us/data/jj206878
#Kerezo covers pretty much exactly what you want to do here: Add Data Annotation To Entity Framework(Or Linq to SQL) generated class
It is not possible to auto generate the data annotations automatically.
I'm just starting to use Entity Framework Designer. I would like to ask how should I create my Entity files. I would like to have like 10 tables and all of them will be linked to at least one other table by some row. Should I create just one file and put all my models there or create a separate file for each model.
I don't know if this is even a question but I could find my answer on Google. I didn't know how to define it actually... :D
So if you have any tips on how I should model my database that will be awesome. Also if you have any more information on when I should use different Entity files that will be useful too.
I have used MySQL designer in the past but in there as far as i can remember you just move the model into the designer and you can make relations. So I'm kinda keen into doing that (all models in one Entity File) but wanted to check with you first guys.
just try this plugin for VS http://visualstudiogallery.msdn.microsoft.com/72a60b14-1581-4b9b-89f2-846072eff19d to generate your classes from existing db
Greetings everyone!
Here's the deal, I've got a site that has multiple languages, each language has its own MSSQL database. I tried to add an Entity Framework Data Model for each database, only to find that the partial classes are conflicting with the other EF Data Models. So the column "banner" from one Model conflicts with the column "banner from another Model. I'm trying to make this as universal as possible by not naming the columns differently but instead dynamically changing the Model I'm using when a specific language is selected.
Any ideas? I'd really appreciate the help!
Tom
If those DB have same schema, all you need is one model. Then based on user's language, connect to relevant DB.
I think its quite usual task, but still solutions I saw look not so nice.
For example in Qt used approach based on MVC pattern -- you must assign all connections manually.
Or I remember one PHP engine where pages were creating from DB schema.
Which are other approaches? Which one you are prefer? What are the best practices?
Usually, there is not a one to one mapping from the database to the GUIThere are many subtle combinations that change between how you store the data and how that stored data is visualized and edited by the user.
however, you can automate a datamodel layer in your code with tools like Hibernate. You will still need to use the model as required to present your user interface.