design of orm tool
- by ifree
Hello , I want to design a orm tool for my daily work, but I'm always worry about the mapping of foreign key.
Here's part of my code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
namespace OrmTool
{
[AttributeUsage(AttributeTargets.Property)]
public class ColumnAttribute:Attribute
{
public string Name { get; set; }
public SqlDbType DataType { get; set; }
public bool IsPk { get; set; }
}
[AttributeUsage(AttributeTargets.Class,AllowMultiple=false,Inherited=false)]
public class TableAttribute:Attribute
{
public string TableName { get; set; }
public string Description { get; set; }
}
[AttributeUsage(AttributeTargets.Property)]
public class ReferencesAttribute : ColumnAttribut
{
public Type Host { get; set; }
public string HostPkName{get;set;}
}
}
I want to use Attribute to get the metadata of Entity ,then mapping them,but i think it's really hard to get it done;
public class DbUtility
{
private static readonly string CONNSTR = ConfigurationManager.ConnectionStrings["connstr"].ConnectionString;
private static readonly Type TableType = typeof(TableAttribute);
private static readonly Type ColumnType = typeof(ColumnAttribute);
private static readonly Type ReferenceType = typeof(ReferencesAttribute);
private static IList<TEntity> EntityListGenerator<TEntity>(string tableName,PropertyInfo[] props,params SqlParameter[] paras) {
return null;
}
private static IList<TEntity> ResultList()
{
return null;
}
private static SqlCommand PrepareCommand(string sql,SqlConnection conn,params SqlParameter[] paras) {
SqlCommand cmd = new SqlCommand();
cmd.CommandText = sql;
cmd.Connection = conn;
if (paras != null)
cmd.Parameters.AddRange(paras);
conn.Open();
return cmd;
}
}
I don't know how to do the next step, if every Entity has it's own foreign key,how do I get the return result ? If the Entity like this:
[Table(Name="ArtBook")]
public class ArtBook{
[column(Name="id",IsPk=true,DataType=SqlDbType.Int)]
public int Id{get;set;}
[References(Name="ISBNId",DataType=SqlDataType.Int,Host=typeof(ISBN),HostPkName="Id")]
public ISBN BookISBN{get;set;}
public .....more properties.
}
public class ISBN{
public int Id{get;set;}
public bool IsNative{get;set;}
}
If I read all ArtBooks from database and when I get a ReferencesAttribute how do I set the value of BookISBN?
