I'm coming the linq-to-SQL world and I want to create a new linq-to-EF6 datacontext.
With Linq-to-SQL, you just create a new data model that outputs a designer onto which you drag and drop tables from an existing database. Here, I tried creating a file with Add -> EF 6.x DbContext Generator and I'm not getting a designer where I can drag and drop tables from the database; instead I'm getting 2 .tt files that are black. I've looked online and most tutorials are about code-first approach but in my case I already have the database.
What do I need to do to create the datacontext that I can use in Linq-to-EF?
Thanks.
Add a "ADO.Net Entity Data Model" to your project.
Create your model from scratch or from an existing database
Add a "EF 6.x DbContext Generator" to your project.
Edit the Model.tt file and replace "$edmxInputFile$" by the name of your EDMX file
Edit the Model.Context.tt file and replace "$edmxInputFile$" by the name of your EDMX file
The *.tt files are T4 templates, which are basically code that generate code. Their role here is to parse the EDMX file for you, and generate the associated entities (Model.tt) and DbContext (Model.Context.tt).
To execute a T4 template (for example to update the generated DbContext/entities once you've modified your edmx), right click on the *.tt file and click on "run custom tool".
Add ADO.NET Entity Data Model to your project. It will give you the chance to choose existing database as source of the model.
Related
How to create a SQL Server database using Entity Framework databbase-first code?
I've mistakenly deleted the database from SQL Server, but I've added EDO in model at my VS 2017 project. So, now I've EDO code, can I restore database with the help of that code ?
If you are able to open edmx in Model Browser in Visual Studio, you can generate script for database by right clicking on edmx diagram. Select Generate Database from Model.
FYI : This will generate only basic structure. Not stored procedure, udf's etc.
And you will get script as below.
Exporting an Entity Data Model to a SQL-Server database
Open the SQL Server Management Studio.
Right click on Databases, select New Database
Type MyFirstEF on Database name. Click OK.
We're going to set the connection properties for your database from Visual Studio:
Right-click on the EDM design mode, select Generate Database from Model
Click on New Connection.
Type your SQL-Server host name on Server name field.
Select the database you created in Step 3 on the field Select or enter a database name. Click OK.
Click Next.
Choose a version of Entity Framework that you use . Click Next.
You have just generated the script to create the database.
For step by step walk-through click here
I followed the directions as detailed in this answer, and my enumeration was saved and can be utilized throughout the app. But in the case that I wanted to add additional options or change the names of existing options, how do I that?
I know I can do so by editing the EDMX file by hand in a text editor. I'd rather do it within Visual Studio in a fashion similar to how I generated the enumeration to begin with if it's possible.
You can use the entity data model browser to update this. In your menu bar, navigate to View -> Other Windows -> Entity Data Model Browser. I think you need to have your edmx file open to see this option. That opens a model browser window and under the "Enum Types" folder you can double click your enum and update it.
I am looking for a tool like mssql workbench where I can draw my database diagram, but for mssql instead. I am programming in asp.net core and would like to have the tool auto generate a diagram based on my existing models, but also let me modify (but not necessarily generate the classes) the diagram after.
You can use "Database Diagrams" feature from MSSQL Management Studio.
Open MSSQL Management Studio, Connect to the SQL Server and select the database.
Under selected database you should be able to find node "Database Diagram". Right click on it and select "Add new diagram".
You can create diagram from the existing tables in the database and also create new tables as well as modify existing table.
You also can save the diagram as JPEG format.
I am writing a test app, using Entity Framework with model-first approach. I had created an EDM model with tables, than created a SQL Server CE database, created connection to db and than Master created a file *.edmx.sqlce with big sql script. What i must do next? How to use it?
You need to execute the script against the database which will create the database for your model. There should be a "Play" icon in the toolbar (similar to a "Play" button on old cassete players) you can click to execute the script.
I am currently learning C# and LINQ. I have lots of questions about them. Basically, I need a step by step tutorial.
I suppose the dbml file is the configuration file of the database. If I double click the dbml file VS will open it in a design diagram. Can I create/delete/modify tables here? I can use add new item to add the LINQ to SQL Classes to get a dbml file?
What's next? Generate tables in database? Generate SQL script? Generate cs files? When? How?
The DBML file is not related to the database server at all. It's a completely client side thing. It's essentially a set of information about your tables in the database and how you're going to map them to .NET objects.
Of course, you can drag a table from a database and have Visual Studio infer some information for you automatically, but changing the file will not affect the database. You can create a DBML file from scratch without any database too.
Internally, the DBML file is simply an XML file that's fed into a custom tool by Visual Studio and generates .cs files representing the LINQ object model for your database from it.
The DBML file is mapping that defines your classes based on your database schema. Yes, it defines your (default) connection string, but it doesn't "configure" your database at all.
Linq to Sql uses a database-first approach where you have the database and model your classes after the DB schema. By dragging & dropping the table onto there, you'll be automating the creation of the classes so you don't have to type them out. You can change property names etc from there and the mapping between the property and its correct database column name will remain intact.
this link learn how to create dbml File in your Project :
http://dotnetlearners.com/linq/linq-to-sql-creating-dbml-file
Implement LINQ to SQL first we have to create the DBML file, the DBML file contains the C# source code which allow us to write the LINQ Queries to SQL. Here is the step by step process to generate dbml file.
Right click on the project (or project folder) and select the option Add New Item.
add-new-item
Select LINQ to SQL Classes Template and Give Name as MyDB.dbml.
linq-to-sql-classess
Click on Yes when the below confirmation displayed.
dialog
MyDB.dbml file will be added under App_Code folder.
dbml
Expand Server Explorer and Right click on the Data Connections and select the option Add Connection.
add-connection
Add Connection Pop up will be opened, give the SQL Server details and select the then click on OK button.
server-detail
Database will be added under Data Connections as shown below.
server-explorer
Drag the table in the left pane and if primary key & foreign key relations are there then it will automatically show as shown below.
drag-tables
Drag the stored procedures to the right pane.
drag-store-procedures
Related C# code will be automatically generated and we can see by opening the file MyDB.designer.cs.
dbml-designer-cs
Yes, the DBML file is created when you add a Linq to SQL class. In the designer (what you see when you double click the DBML file) you can drag tables (from the server explorer) onto it. You can then reference these tables in your code. There are more than a few getting started tutorials out there:
Check this SO question for details:
https://stackoverflow.com/questions/481244/can-anyone-recommend-a-good-tutorial-for-learning-linq2sql
Walkthrough: Simple Object Model and Query (C#)
Consider SqlMetal
PK :-)