项目中使用的自定义数据访问类（复杂查询，复杂操作）

using System;
using System.Collections.Generic;
using System.Text;
using MySql.Data.MySqlClient;
using GoMusic.Data.MySqlClient;
using GoMusic.Data;
using Gta.VSL.Entities;
using System.Data;

namespace Gta.VSL.MySqlClient
{
    /// <summary>
    /// 表的数据访问类
    /// </summary>
	public partial class CourseCycleRepository
    {
        /// <summary>
        /// 从搜索类里面拼接参数化的SQL字符串
        /// </summary>
        /// <param name="searchEntity">搜索类</param>
        /// <param name="sqlParams">搜索的参数，不能传入Null</param>
        /// <param name="whereSqlAppender">安全的SQL语句</param>
        protected override void GetWhereSqlBySearchItemCore(SearchCourseCycle searchEntity, List<MySqlParameter> sqlParams, StringBuilder whereSqlAppender)
        {
            if (searchEntity.CoursePlan_IdEqual.HasValue)
            {
                this.CombineSqlQueryCondition(c => c.CoursePlan_Id,
                   ConditionCompareChar.Equal,
                   searchEntity.CoursePlan_IdEqual.Value,
                   whereSqlAppender,
                   sqlParams);
            }
            if (searchEntity.RecordStatusEqual.HasValue)
            {
                this.CombineSqlQueryCondition(c => c.RecordStatus,
                   ConditionCompareChar.Equal,
                   searchEntity.RecordStatusEqual.Value,
                   whereSqlAppender,
                   sqlParams);
            }
            if (searchEntity.StartTimeLessThanEqual.HasValue)
            {
                this.CombineSqlQueryCondition(c => c.StartTime,
                   ConditionCompareChar.LessThanEqual,
                   searchEntity.StartTimeLessThanEqual.Value,
                   whereSqlAppender,
                   sqlParams);
            }
            if (searchEntity.EndTimeGreateThanEqual.HasValue)
            {
                this.CombineSqlQueryCondition(c => c.EndTime,
                   ConditionCompareChar.GreaterThanEqual,
                   searchEntity.EndTimeGreateThanEqual.Value,
                   whereSqlAppender,
                   sqlParams);
            }
        }

        /// <summary>
        /// 课程在该周是否存在课程安排
        /// </summary>
        /// <param name="weekNum">周编号</param>
        /// <param name="courseId">课程Id</param>
        /// <returns></returns>
        public bool HasCourseCycle(int weekNum, int courseId)
        {
            string formatString = @"SELECT
                                COUNT(*)
                                FROM
                                coursecycle
                                LEFT JOIN courseplan ON coursecycle.CoursePlan_Id = courseplan.Id
                                LEFT JOIN course ON courseplan.Course_Id = course.Id
                                WHERE
                                coursecycle.CycleCount = {0} AND
                                course.Id = {1} AND
                                coursecycle.RecordStatus = 1";
            string sqlString = string.Format(formatString, weekNum, courseId);
            object count = MySqlDbHelper.ExecuteScalar(CommandType.Text, sqlString);
            if (Convert.ToInt32(count) > 0)
            {
                return true;
            }
            else
            {
                return false;
            }
        }
	}
}