먼저 EF 코드가있는 고유 키

먼저 EF 코드가있는 고유 키

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내 프로젝트에 다음 모델이 있습니다.

public class Category
{   
    public Guid ID { get; set; }
    [Required(ErrorMessage = "Title cannot be empty")]
    public string Title { get; set; }
}

Title고유 키로 만들려고하는데 솔루션을 검색했지만 찾을 수 없었습니다. 방법을 제안 해 주시겠습니까?

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불행히도 EF는 고유 키를 전혀 지원하지 않기 때문에 먼저 코드에서 고유 키로 정의 할 수 없습니다 (다음 메이저 릴리스에서 계획 중입니다). 할 수있는 일은 사용자 지정 데이터베이스 초기화 프로그램을 만들고 SQL 명령을 호출하여 수동으로 고유 인덱스를 추가하는 것입니다.

public class MyInitializer : CreateDatabaseIfNotExists<MyContext>
{
  protected override void Seed(MyContext context)
  {
    context.Database.ExecuteSqlCommand("CREATE UNIQUE INDEX IX_Category_Title ON Categories (Title)");
  }
}

그리고 애플리케이션의 부트 스트랩에서이 이니셜 라이저를 설정해야합니다.

Database.SetInitializer<MyContext>(new MyInitializer());

편집하다

이제 (EF 6.1 이상) 고유 한 제약 조건을 쉽게 가질 수 있습니다.

[Index("TitleIndex", IsUnique = true)]
 public string Title { get; set; }

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먼저 사용자 정의 속성 클래스를 만듭니다.

[AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = true)]
public class UniqueAttribute : ValidationAttribute
{
   public override Boolean IsValid(Object value)
    {
        // constraint implemented on database
        return true;
    }
}

그런 다음 수업에 추가하십시오.

public class Email
{
    [Key]
    public int EmailID { get; set; }

    public int PersonId { get; set; }

    [Unique]
    [Required]
    [MaxLength(100)]
    public string EmailAddress { get; set; }
    public virtual bool IsDefault { get; set; }
    public virtual Boolean IsApprovedForLogin { get; set; }
    public virtual String ConfirmationToken { get; set; }

    [ForeignKey("PersonId")]
    public virtual Person Person { get; set; }
}

그런 다음 DbContext에 이니셜 라이저를 추가합니다.

public class Initializer : IDatabaseInitializer<myEntities>
{
    public void InitializeDatabase(myEntities context)
    {
        if (System.Diagnostics.Debugger.IsAttached && context.Database.Exists() && !context.Database.CompatibleWithModel(false))
        {
            context.Database.Delete();
        }

        if (!context.Database.Exists())
        {
            context.Database.Create();

            var contextObject = context as System.Object;
            var contextType = contextObject.GetType();
            var properties = contextType.GetProperties();
            System.Type t = null;
            string tableName = null;
            string fieldName = null;
            foreach (var pi in properties)
            {
                if (pi.PropertyType.IsGenericType && pi.PropertyType.Name.Contains("DbSet"))
                {
                    t = pi.PropertyType.GetGenericArguments()[0];

                    var mytableName = t.GetCustomAttributes(typeof(TableAttribute), true);
                    if (mytableName.Length > 0)
                    {
                        TableAttribute mytable = mytableName[0] as TableAttribute;
                        tableName = mytable.Name;
                    }
                    else
                    {
                        tableName = pi.Name;
                    }

                    foreach (var piEntity in t.GetProperties())
                    {
                        if (piEntity.GetCustomAttributes(typeof(UniqueAttribute), true).Length > 0)
                        {
                            fieldName = piEntity.Name;
                            context.Database.ExecuteSqlCommand("ALTER TABLE " + tableName + " ADD CONSTRAINT con_Unique_" + tableName + "_" + fieldName + " UNIQUE (" + fieldName + ")");
                        }
                    }
                }
            }
        }
    }
}

마지막으로 Global.asax.cs 내부 Application_Start에 Initializer를 추가하십시오.

System.Data.Entity.Database.SetInitializer<MyApp.Models.DomainModels.myEntities>(new MyApp.Models.DomainModels.myEntities.Initializer());

That's it. based on the vb code at https://stackoverflow.com/a/7426773

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Here is the VB.Net version - note the implementation of generics that is a little different, at the class level.

Public Class MyInitializer(Of T As DbContext)
    Inherits CreateDatabaseIfNotExists(Of T)
    Protected Overrides Sub Seed(context As T)
        context.Database.ExecuteSqlCommand("CREATE UNIQUE INDEX IX_Category_Title ON Categories (Title)")
    End Sub
End Class

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I create this class (which ws enhanced from another Stackoverflow answer -Execute a large SQL script (with GO commands)), which allows me to drop in the SQL scripts into a directory, and have them all executed each time they are required (Seed, or Migration). I'm not going to leave this open after I deploy to production, but during development it makes it easy to apply scripts each time the DB is recreated.

using System;
using System.Collections.Generic;
using System.Data.SqlClient;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
//dll Microsoft.SqlServer.Smo
//dll Microsoft.SqlServer.Management.Sdk.Sfc
//dll Microsoft.SqlServer.ConnectionInfo
using Microsoft.SqlServer.Management.Common;
using Microsoft.SqlServer.Management.Smo;
using Monitor.Common;

namespace MonitorDB.DataLayer.Migrations
{
  public class ExecuteSQLScripts :Monitor.Common.ExceptionHandling
  {
    public ExecuteSQLScripts()
    {
}

public bool ExecuteScriptsInDirectory(DBContext.SolArcMsgMonitorContext context, string scriptDirectory)
{
  bool Result = false;
  try
  {
    SqlConnection connection = new SqlConnection(context.Database.Connection.ConnectionString);
    Server server = new Server(new ServerConnection(connection));

    DirectoryInfo di = new DirectoryInfo(scriptDirectory);
    FileInfo[] rgFiles = di.GetFiles("*.sql");
    foreach (FileInfo fi in rgFiles)
    {

      FileInfo fileInfo = new FileInfo(fi.FullName);
      string script = fileInfo.OpenText().ReadToEnd();

      server.ConnectionContext.ExecuteNonQuery(script);
    }
    Result = true;
  }
  catch (Exception ex)
  {
    CatchException("ExecuteScriptsInDirectory", ex);
  }
  return Result;
}

} }

Here is what the VS Solution looks like:

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I found this solution which although not creating a unique-key in the SQL level, it uses DataAnnotations validation, check it out:

http://blogs.microsoft.co.il/blogs/shimmy/archive/2012/01/23/validationattribute-that-validates-a-unique-field-against-its-fellow-rows-in-the-database.aspx

참고URL : https://stackoverflow.com/questions/5701608/unique-key-with-ef-code-first