Wednesday, March 22, 2017
In the previous blog we created the NorthwindCafe database with Entity Framework Core. Now we are going to seed the database so that we can work with the data.
Here are the steps to seed the NorthwindCafe database:
1. Create a file call DBInitializer in the NorthwindCafe.Web folder, in the file type in the following code
The code is pretty straight forward it checks for categories in the database with the line
context.Categories.Any()
if there are Categories in the database then it just get out of the method else it populates the database with the categories object
2. Now open the Startup.cs file and add the NorthwindContext to the Configure method
Add the line DbIntitializer.Initialize(context) to the end of the method to seed the database on startup Run the application and the Categories table will be populated with seed data
Here are the steps to seed the NorthwindCafe database:
1. Create a file call DBInitializer in the NorthwindCafe.Web folder, in the file type in the following code
using System.Linq;
namespace NorthwindCafe.Web.Models
{
public class DbInitializer
{
public static void Initialize(NorthwindContext context)
{
context.Database.EnsureCreated();
if(context.Categories.Any())
{
return;
}
var categories = new Category[]
{
new Category {Name = "Coffee", Description="Coffee", Products = new Product[] { new Product { Name = "Dark Roast", Description = "Dark Roast", Price = 2.0M } } },
new Category {Name = "Tea", Description="Tea", Products = new Product[] { new Product { Name = "Chai", Description = "Chai", Price = 1.5M } } },
new Category {Name = "Pastry", Description="Pastry", Products = new Product[] { new Product { Name = "Cupcake", Description = "Cupcake", Price = 1.25M } } },
new Category {Name = "Food", Description = "Food", Products = new Product[] { new Product { Name = "Hamburger", Description = "Hamburger", Price = 5.0M } } }
};
foreach (var c in categories)
{
context.Categories.Add(c);
}
context.SaveChanges();
}
}
}
The code is pretty straight forward it checks for categories in the database with the line
context.Categories.Any()
if there are Categories in the database then it just get out of the method else it populates the database with the categories object
2. Now open the Startup.cs file and add the NorthwindContext to the Configure method
public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory, NorthwindContext context)
{
app.UseStaticFiles();
app.UseMvc(config =>
{
config.MapRoute(
name: "Default",
template: "{controller}/{action}/{id?}",
defaults: new { controller = "Home", action = "Index" }
);
});
DbInitializer.Initialize(context);
}
Add the line DbIntitializer.Initialize(context) to the end of the method to seed the database on startup Run the application and the Categories table will be populated with seed data
The Products table will be populated as well notice how the CategoryId has been assigned to the appropriate category
- How To Create An ASP.NET Core Application From Scratch
- ASP.NET Core : Add jQuery, Bootstrap, AngularJS Using bower.json
- Enable MVC On ASP.NET Core Application
- ASP.NET Core : Create Our First Controller and View
- ASP.NET Core : Adding The Default View With _ViewStart.cshtml
- ASP.NET Core : Create A Responsive Layout With Bootstrap
- ASP.NET Core : Adding Font-Awesome For Northwind Cafe Navigation Icons
- ASP.NET Core : Add .json Configuration Files With Microsoft.Extensions.Configuration Library
- ASP.NET Core : Entity Framework Core Models For Northwind Cafe
- ASP.NET Core : Create The NothwindContext ( EntityFrameworkCore )
- ASP.NET Core : Configure project.json File To Support Entity Framework Core
- ASP.NET Core : Add NorthwindContext To Startup Class And Create Database
- ASP.NET Core: Seeding The NorwindCafe Database
- ASP.NET Core: Add Logging To The NorthwindCafe Application
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context.Categories.Any() is not working on my project.
ReplyDeleteWhat's happening is, it inserts the data everytime my application execute. Im using VSCode EntityFrameworkCore in Ubuntu Linux
Does your Categories object have an Id? I suspect it is not executing a check on the database with just .Any() alone.
ReplyDeleteYou can try the following: if (context.Categories.Any(x => x.Id > 0)) { }
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This approach seeds the database using EF Core's built-in functionality, making it easy cookout chicken wrap to manage initial data for your application.
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