一直用EF Fluent Api 做MapConfiguration
所以遇到了唯一约束这个瓶颈
使用唯一约束的两种方式：
方式1 自定义唯一约束
[AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = true)]
public class UniqueAttribute : ValidationAttribute
{
public override Boolean IsValid(Object value)
{
//校验数据库是否存在当前Key
return true;
}
}
在Model类中使用
public class Email
{
[Key]
public int EmailID { get; set; } public int PersonId { get; set; } [Unique]
[Required]
[MaxLength()]
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; }
}
方式2 扩展DataBaseSetInitializer 使用Sql语句添加
public class MyInitializer : CreateDatabaseIfNotExists<MyContext>
{
protected override void Seed(MyContext context)
{
context.Database.ExecuteSqlCommand("CREATE UNIQUE INDEX IX_Category_Title ON Categories (Title)");
}
}
在DbContext中使用Database.SetInitializer<MyContext>(new MyInitializer());
方式3 扩展IDatabaseInitializer
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()[]; var mytableName = t.GetCustomAttributes(typeof(TableAttribute), true);
if (mytableName.Length > )
{
TableAttribute mytable = mytableName[] as TableAttribute;
tableName = mytable.Name;
}
else
{
tableName = pi.Name;
} foreach (var piEntity in t.GetProperties())
{
if (piEntity.GetCustomAttributes(typeof(UniqueAttribute), true).Length > )
{
fieldName = piEntity.Name;
context.Database.ExecuteSqlCommand("ALTER TABLE " + tableName + " ADD CONSTRAINT con_Unique_" + tableName + "_" + fieldName + " UNIQUE (" + fieldName + ")");
}
}
}
}
}
}
}
在DbContext中使用
System.Data.Entity.Database.SetInitializer<MyApp.Models.DomainModels.myEntities>(new MyApp.Models.DomainModels.myEntities.Initializer());
参考文献：http://stackoverflow.com/questions/5701608/unique-key-with-ef-code-first