Db Attribute(Custom ORM ) Usage

Db Attribute Usage
1. Attribute Defination

Db

  [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, AllowMultiple = false, Inherited = true)]    public class DataBaseAttribute : System.Attribute    {        public string Name { get; private set; }        public DataBaseAttribute(string name)        {            Name = name;        }    }

 

DataTable

[AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, AllowMultiple = false, Inherited = true)]    public class DataTableAttribute : System.Attribute    {        public string Name { get; private set; }        public DataTableAttribute(string name)        {            Name = name;        }    }

 

Primary Key

 [AttributeUsage(AttributeTargets.Property, AllowMultiple = false,Inherited = false)]    public class PrimaryKeyAttribute : System.Attribute    {        public bool IsAutoIncreased { get; private set; }        public string Name { get; private set; }        public PrimaryKeyAttribute(string name,bool isAutoIncreased)        {            IsAutoIncreased = isAutoIncreased;            Name = name;        }    }

 
2. Use Attribute to Entity

Db

    [DataBase("northwnd")]    public class IoriRepository<T> : IRepository<T> where T : new()

 

DataTable And Primary Key

   [DataTable("Products")]    public class ProductEntity    {        [PrimaryKey("ProductId",true)]        public int ProductId { get; set; }        public string ProductName { get; set; }        public int SupplierId { get; set; }        public int CategoryId { get; set; }        public string QuantityPerUnit { get; set; }        public decimal UnitPrice { get; set; }        public Int16 UnitsInStock { get; set; }        public Int16 UnitsOnOrder { get; set; }        public Int16 ReorderLevel { get; set; }        public bool Discontinued { get; set; }    }

 

3. Get Attribute Implementation

 public static class AttributeHelper     {        public  static TAttrType GetFirstAttr<TAttrType, TClassType>(bool isInherit) where TAttrType : System.Attribute        {            var attrs = (TAttrType[])(typeof(TClassType).GetCustomAttributes(typeof(TAttrType), isInherit));            return attrs.FirstOrDefault();        }    }

////get db name            var dbAttr = AttributeHelper.GetFirstAttr<DataBaseAttribute, IoriRepository<T>>(false);            if (dbAttr == null)                throw new Exception("failed to get Database name , check if you forgot to set Database Attribute for Repository<T>");

 

Similarly , Can use the same method to get DataTable Attribute And Primary Key Attribute