I am quite new to the Entity Framework, and only have recently started looking into it. I have been using Linq to SQL for sometime now in a C# enviroement and found it really wonderful to use.
Currently I use sqlmetal to generate a DataContext File (Linq to SQL).
Now after some time I thought it would be nice to use to the Entity Framework, (Linq to Entities), I can see that in some respect there are syntatical similarities between the two, i.e. accessing and creating new instances providing the connection string.
However what Im interested in is when the mapping is generated, is there a way to automatically import all the stored procedures, similar to how sqlmetal does it. So that I dont have to import each one individually.
Thank you in advance.
In the Model Designer (inside Visual Studio, default view option for *.edmx files)
right click --> Update Model from Database
in the "Add" tab of the resulting dialog you can select any or all Stored Procedures.
Edit: Here's a screenshot of the dialog I'm talking about, found at a tutorial at robbagby.com
Related
Is it possible to automatically convert a lot of C# classes to SQL Server database tables ?
I need to import some xml files into SQL Server but using SSIS the runtime stops working as soon as I select the xsd file. However I easily converted the xsd to class files so that's why I am asking if its possible to have a workaround...
You can use Entity Framework Code First functionality, with a little extra work to get the tables done in your database.
There you have a good post on it by ScottGu
Yes, it's possible to automatically do this. Entity Framework has a model called Code First, which essentially does this: takes your C# classes and creates the database and tables automatically for you.
Take a look at this post by Scott Guthrie.
Other option you might test is DataSet.ReadXml() function. Drawback is the Dataset can't handle complexType="mixed", but it deals well with large files (my files had about 50M each). All tables and columns are named by XML tags and relations are autogenerated by DataSet itself.
I've made a local database for a C# project:
I know basic SQL commands, but haven't worked with databases in C#.
What I'd like to know specifically is:
How to read from the database (query)
How to add and update rows
The database only consists of 3 tables, so I don't think anything fancy is needed.
First, you should learn a bit about various technologies and APIs for connecting with a database.
The more traditional method is ADO.NET, which allows you to define connections and execute SQL queries or stored procedures very easily. I recommend digging up a basic tutorial on ADO.NET using Google, which may differ depending on what type of project you're creating (web app, console, WinForms, etc).
Now days, ORMs are becoming increasingly popular. They allow you to define your object model in code (such as every database table would be a class, and columns would be properties on that class) and bind to an existing database. To add a new row to a table, you'd just create an instance of a class and call a "Save" method when you're done.
The .NET framework has LINQ to SQL and the Entity Framework for this sort of pattern, both of which have plenty of tutorials online. An open source project I really like is Castle Active Record, which is built on top of NHibernate. It makes defining ORMs quite easy.
If you have specific questions about any of the above, don't hesitate to post a new question with more specific inquiries. Good luck!
Update:
I thought I'd also put in one last reference as it seems you might be interested in working with local database stores rather than building a client/server app. SQLite allows you to interact with local stores on the file system through SQL code. There's also a .NET binding maintained by the SQLite guys (which would in theory allow you to work with the other platforms I mentioned): http://system.data.sqlite.org/index.html/doc/trunk/www/index.wiki
You can use SQLCE.
This blog will give you a good start.
http://weblogs.asp.net/scottgu/archive/2011/01/11/vs-2010-sp1-and-sql-ce.aspx
Here is a small tutorial that should be helpful to you.
You can make use of the SqlDataReader to read data
and the SqlCommand to Insert Update Delete rows from your tables.
http://www.dotnetperls.com/sqlclient
You could use it by adding following to your Startup.cs
services.AddDbContext<DemoDbContext>(options => options.UseSqlite("Filename=data.db"));
I made the UI side of the project, but now I need to have a database. How can I create it with Visual Studio 2010? I don't have any idea about how to retrieve data with C#. I know SQL but can you give me some examples of that (C# with SQL)?
What Joe talks about and what the post by Scott Hanselman describes is called "Code First". With Entity Framework, there are two other (easy) ways to create a database with Visual Studio 2010 tooling.
One would be to use a Entity Data Model (.edmx) file to create your model (classic Entity Relationship model) and then right click on the model and choose "Generate Database from Model", connect to SQL server and you're done. This is called Model First.
The other technique, which is called "Database First", is when you have an existing Database (or you can create your database directly from SQL Server), and you create an Entity Data Model based on that (you actually get to choose between Database first and model first from the Add-> Entity Data Model dialog). You select the tables, views and stored procedures you want to add, hit finish and you're set.
in both cases, When you build your soultion, you get a data context class that you can use to access your data which is pretty straightforward as well (pretty much the same way as described in scott's blog post).
There are lots of ways to do this, something you might want to take a look at is EF code first where you can create models in code and then generate the database based off of those models.
http://www.hanselman.com/blog/SimpleCodeFirstWithEntityFramework4MagicUnicornFeatureCTP4.aspx
I have been using the model-first approach for about two weeks now and it works great. I also used the "Generate Database from Model" option, which results in a DDL being generated, which in turn is an SQL script that I run to create the database. If I add entities to my model and update the DDL it does not add an alter statement to entities that already exist, so if I were to run the script again it deletes previous tables and recreates them and deletes any data. Is there any way I can prevent this? Or do it differently? Or change my approach?
Try Entity Designer Database Generation Power Pack. http://blogs.msdn.com/b/adonet/archive/2010/02/08/entity-designer-database-generation-power-pack.aspx
Not really the DDL approach has two problems, and one is not really fixable:
As you found out it creates / recreates a database. No maintenance.
More important: It is stupid. As in: not smart. It can only use a very small but most common subset of what one can do in SQL Server, so it basically is only feasible for the most simplistic databases.
If you do not beliee the second point, read up the complete DDL for SQL Server in the documentation and be surprised how many things one can do for not so common settings. All are transparent to the SQL UQuery side. And the vast majority of advanced features are not usable in EF4 DDL.
I'm very new to C#, so please forgive me if I've overlooked something here. I've created a database using Visual Studio (add new item > service-based database) called LoadForecast.mdf. I then created a table called ForecastsDB and added some fields.
My main question is this: I've created a console application with the intention of writing some data to the newly created database. I've added LoadForecast.mdf as a data source for my program, but is there anything else I should do? I saw an example where the next step was adding a "data diagram", but this was for a visual application, not a console application. Do I still need to diagram the database for my console app? I just want to be able to write new records out to my database table and wasn't sure if there were any other things I needed to do for the VS environment to be "aware" of my database. Thanks for any advise!
Well, it depends on what data access technology you want to use. You can use straight SqlClient, you can use untyped data sets, you can use strongly typed data sets, you can use LINQ to SQL, you can use Entity Framework.
If you're not sure, then probably the most fun would be LINQ to SQL, so I recommend you follow a tutorial first and then come back to your app. Eg. ScottGu's LINQ to SQL (Part 4 - Updating our Database), or MSDN's How to: Insert Rows Into the Database.
There are also video guides, like VS2008 Training Kit: Using LINQ with Relational Data or MSDN Webcast: Using LINQ with Relational Data (Level 100).