提到DbContext,對(duì)于經(jīng)常使用DbFirst模式的開(kāi)發(fā)者來(lái)說(shuō)已經(jīng)再熟悉不過(guò)了，EntityFramework全靠這員大將。它的作用是代表與數(shù)據(jù)庫(kù)連接的會(huì)話，提供了查詢(xún)、狀態(tài)跟蹤、保存等功能。
還有一個(gè)重要的對(duì)象是DbSet，對(duì)實(shí)體類(lèi)型提供了集合操作，比如Add、Attach、Remove。繼承了DbQuery，所以可以提供查詢(xún)功能。
ActDbContext.cs示例
using Microsoft.EntityFrameworkCore;
using Rdf.Domain.Entities.Act;
namespace Rdf.EntityFrameworkCore
{
public class ActDbContext : DbContext
{
public ActDbContext(DbContextOptions<ActDbContext> options)
: base(options)
{
}
#region Act
public DbSet<User> Users { get; set; }
public DbSet<Role> Roles { get; set; }
public DbSet<OrganizationUnit> OrganizationUnits { get; set; }
public DbSet<Module> Modules { get; set; }
public DbSet<Function> Functions { get; set; }
public DbSet<Edition> Editions { get; set; }
public DbSet<Tenant> Tenants { get; set; }
public DbSet<UserRole> UserRoles { get; set; }
public DbSet<RoleModule> RoleModules { get; set; }
public DbSet<ModuleFunction> ModuleFunctions { get; set; }
public DbSet<UserOrganizationUnit> UserOrganizationUnits { get; set; }
#endregion
protected override void OnModelCreating(ModelBuilder builder)
{
builder.Entity<Role>().ToTable("Act_Role");
builder.Entity<Role>().HasKey(k => k.Id);
builder.Entity<Role>().Property(t => t.Id).HasColumnName("RoleId");
base.OnModelCreating(builder);
}
}
}
說(shuō)明：DbContext 需要引用 Microsoft.EntityFrameworkCore
增加對(duì)EF的支持
我們打開(kāi)Startup.cs修改ConfigureServices(IServiceCollection services)方法，增加對(duì)EF的支持
// This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
// Add framework services.
// 增加對(duì)EF的支持
services.AddDbContext<ActDbContext>(options => options.UseSqlServer(Configuration.GetConnectionString("SqlServerConnection")));
services.AddMvc();
}
上面的SqlServerConnection是我們的數(shù)據(jù)庫(kù)連接字符串，它的配置在project.json文件中：
{
"Logging": {
"IncludeScopes": false,
"LogLevel": {
"Default": "Debug",
"System": "Information",
"Microsoft": "Information"
}
},
"ConnectionStrings": {
"SqlServerConnection": "Server=.;Database=RdfDb;User ID=sa;Password=sh.123456;"
}
}
這樣，實(shí)際上我們就完成了，但是我們后面會(huì)用到，我們目前不操作數(shù)據(jù)。
