插入一次EF代码优先种子数据

在我的EF代码优先的MVC应用程序中,我正在播种SuperUser基本数据.稍后,可以从应用程序界面更改其值.

但是我面临的问题-每次运行应用程序时,此种子数据都会刷新.我不想重设.有什么办法可以避免这种情况？

//This is my DatabaseContext.cs -
public partial class DatabaseContext : DbContext
{
    public DatabaseContext() : base("name=EntityConnection")
    {
       Database.SetInitializer(new MigrateDatabaseToLatestVersion<DatabaseContext, Migrations.Configuration>()); 
    }
}

//This is my Configuration.cs-
internal sealed class Configuration : DbMigrationsConfiguration<DatabaseContext>
{
    public Configuration()
    {
        AutomaticMigrationsEnabled = true;
        AutomaticMigrationDataLossAllowed = false;
    }

    protected override void Seed(DatabaseContext context)
    {
        User user = new User()
            {
                UserId = 1,
                EmailAddress = "xyz@abc.com",
                LoginPassword = "123",                
                CurrentBalance = 0,
            };

        context.Users.AddOrUpdate(user);
    }
}

解决方法:

您可以先检查表是否为空：

if (!context.Users.Any())
{
    User user = new User()
    {
        UserId = 1,
        EmailAddress = "xyz@abc.com",
        LoginPassword = "123",
        CurrentBalance = 0
    };
    context.Users.AddOrUpdate(user);
}

或查看是否存在UserId = 1的行：

if (context.Users.Where(a => UserId == 1).Count() == 0) { ...

标签：entity-framework-6,code-first,c
来源： https://codeday.me/bug/20191025/1930631.html