using Ant.Common;
using Ant.Utility;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Ant.DbExpressions
{
    /// <summary>
    /// 
    /// </summary>
    public class DbUpdateExpression : DbExpression
    {

        /// <summary>
        /// 
        /// </summary>
        /// <param name="table"></param>
        public DbUpdateExpression(DbTable table)
            : this(table, null)
        {
        }
        /// <summary>
        /// 获取解析更新SQL
        /// </summary>
        /// <param name="table"></param>
        /// <param name="condition"></param>
        public DbUpdateExpression(DbTable table, DbExpression condition)
            : base(DbExpressionType.Update, UtilConstants.TypeOfVoid)
        {
            AntUtils.CheckNull(table);

            this._table = table;
            this._condition = condition;
            this.UpdateColumns = new Dictionary<DbColumn, DbExpression>();
        }

        DbTable _table;
        /// <summary>
        /// 表名
        /// </summary>
        public DbTable Table
        {
            get { return this._table; }
        }
        /// <summary>
        /// 更新列
        /// </summary>
        public Dictionary<DbColumn, DbExpression> UpdateColumns
        {
            get; private set;
        }
        

        DbExpression _condition;
        /// <summary>
        /// 查询条件
        /// </summary>
        public DbExpression Condition
        {
            get { return this._condition; }
        }
        /// <summary>
        /// 解析成SQL语句
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="visitor"></param>
        /// <returns></returns>
        public override T Accept<T>(DbExpressionVisitor<T> visitor)
        {
            return visitor.Visit(this);
        }
    }
}