Light ORM Library for .NET

using System;
using System.Data;
using System.Reflection;

namespace Light.Model
{
	/// <summary>
	/// Represents a column based on a field.
	/// </summary>
	internal class FieldColumn : AbstractColumn
	{
		private FieldInfo field;
		
		/// <summary>
		/// Creates a new field column.
		/// </summary>
		/// <param name="field">underlying class field</param>
		/// <param name="name">column name</param>
		/// <param name="dbtype">database data type</param>
		/// <param name="primaryKey">whether this column is a primary key column</param>
		/// <param name="autoIncr">whether this column is an auto-incremented column</param>
		internal FieldColumn(FieldInfo field, string name, DbType dbtype,
		                     bool primaryKey, bool autoIncr)
			: this(field, name, dbtype, 0, primaryKey, autoIncr)
		{
		}
		
		/// <summary>
		/// Creates a new field column.
		/// </summary>
		/// <param name="field">underlying class field</param>
		/// <param name="name">column name</param>
		/// <param name="dbtype">database data type</param>
		/// <param name="size">size of the database data type</param>
		/// <param name="primaryKey">whether this column is a primary key column</param>
		/// <param name="autoIncr">whether this column is an auto-incremented column</param>
		internal FieldColumn(FieldInfo field, string name, DbType dbtype,
		                     int size, bool primaryKey, bool autoIncr)
			: this(field, name, dbtype, size, 0, 0, primaryKey, autoIncr)
		{
		}
		
		/// <summary>
		/// Creates a new field column.
		/// </summary>
		/// <param name="field">underlying class field</param>
		/// <param name="name">column name</param>
		/// <param name="dbtype">database data type</param>
		/// <param name="size">size of the database data type</param>
		/// <param name="precision">precision of the database data type</param>
		/// <param name="scale">scale of the database data type</param>
		/// <param name="primaryKey">whether this column is a primary key column</param>
		/// <param name="autoIncr">whether this column is an auto-incremented column</param>
		internal FieldColumn(FieldInfo field, string name, DbType dbtype, int size,
		                     byte precision, byte scale, bool primaryKey, bool autoIncr)
			: base(name, dbtype, size, precision, scale, primaryKey, autoIncr)
		{
			this.field = field;
		}
		
		/// <summary>
		/// True if this column can be written to. That is,
		/// whether calling the Write method can actually
		/// attempt to write a value into a target object.
		/// </summary>
		public override bool Writeable
		{
			get { return true; }
		}
		
		/// <summary>
		/// True if this column can be read from. That is,
		/// whether calling the Read method will return a valid value.
		/// </summary>
		public override bool Readable
		{
			get { return true; }
		}
		
		/// <summary>
		/// Attempts to write a given value info a given target object.
		/// </summary>
		/// <param name="target">target object</param>
		/// <param name="value">value to write</param>
		public override void Write(object target, object value)
		{
			field.SetValue(target, value);
		}
		
		/// <summary>
		/// Attempts to read a value from a given source object.
		/// </summary>
		/// <param name="source">source object</param>
		/// <returns>value of this column from the source object</returns>
		public override object Read(object source)
		{
			return field.GetValue(source);
		}
	}
}