An ASP.NET | Open-source web framework for .NET Core application can communicate with a SQL Server database using the Entity Framework Core (EF Core) library, which is a lightweight, extensible, and cross-platform version of the Entity Framework. EF Core provides a way to interact with databases using an object-relational mapper (ORM) that maps C# objects to database tables and vice versa. This allows developers to work with the database using C# code, rather than writing raw SQL queries.
Here are the general steps to communicate with a SQL Server database using EF Core in an ASP.NET Core application:
1. Install the required dependencies: You will need to install the Microsoft.EntityFrameworkCore.SqlServer package, which provides EF Core support for SQL Server.
2. Create a DbContext class: This class represents a session with the database and is used to query and save data. The class should inherit from the Microsoft.EntityFrameworkCore.DbContext class and should contain DbSet properties for each of the database tables you want to interact with.
3. Configure the database connection: You will need to configure the connection string to your SQL Server database in the appsettings.json file.
4. Use the DbContext: You can now use the DbContext class to interact with the database. For example, you can use the DbSet properties to query and save data, and the SaveChanges() method to commit the changes to the database.
5. Migrations: You will need to use the EF Core's migrations feature to create and update the database schema.
It's worth noting that there are also other libraries available for connecting to SQL Server databases, such as Dapper and ADO.NET, but EF Core is the most common method.