EF代码首先不创建数据库

问题描述

这是我的代码:

public void ConfigureServices(IServiceCollection services)
{
    services.AddDbContext<AppDbContext>(options =>
    {
     options.UseSqlServer(Configuration.GetConnectionString("AppDbContext"));
    });

    services.AddMvc();
}

这是我的DbContext:

And this is my DbContext:

public class AppDbContext : DbContext
{
    public AppDbContext(DbContextOptions<AppDbContext> options) : base(options)
    {

    }

    public DbSet<Actor> Actors { get; set; }
    public DbSet<Movie> Movies { get; set; }
    public DbSet<MovieActor> MovieActors { get; set; }

}

我的ConnectionString很好.我真的很想知道为什么运行此代码时我的数据库没有生成?断点在 services.AddDbContext 行中命中，但是当我在 AppDbContext 中放置断点时却没有命中.有人可以帮忙吗?我的代码正是这样的 https://docs.microsoft.com/en-us/aspnet/core/data/ef-mvc/intro

And my ConnectionString is just fine. I'm really wondering why my DB is not generating when I run this code? The breakpoint is hitting in the line services.AddDbContext but when I put a breakpoint in AppDbContext it is not hitting. Can anybody help? My code exactly is looks like this https://docs.microsoft.com/en-us/aspnet/core/data/ef-mvc/intro

推荐答案

这是第一次创建您的Db(下面的代码).但是，迁移与创建不同.您可以检查链接( https://msdn.microsoft.com/en-us/library/jj591621(v = vs.113).aspx ).如果要通过代码管理Db，则应在部署管道中涉及DbMigrations脚本的执行，否则就没有太大用处.

This create your Db for first time (code at below). However, migration is different than creation. You can check link ( https://msdn.microsoft.com/en-us/library/jj591621(v=vs.113).aspx ). If you want to manage Db from your code, DbMigrations scripts execution should be involved your deployment pipeline, otherwise it is not much usefull.

也存在自动迁移(自动检测更改并在db上执行)(实体框架，自动应用迁移).但这并不能提供足够的灵活性，我不建议将其用于生产.

Automatic migration (auto detect changes and executed on db) are also exist (Entity Framework, Automatic apply Migrations). But this does not gives much flexibly and I do not recommend for production.

public class AppDbContext : DbContext
{
    public AppDbContext(DbContextOptions<AppDbContext> options) : base(options)
    {
        this.Database.EnsureCreated();
    }

public DbSet<Actor> Actors { get; set; }
..............

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