我的基於asp.net mvc5 +mysql+dapper+easyui 的Web開發框架（1）數據庫訪問（0）

一、數據庫訪問 概述

　　1. 數據庫使用mysql，orm采用dapper框架。dapper框架應用簡單，只是需要自己手寫sql語句，但是對於像我這樣寫了多年sql語句的人來說，這應該不算問題，個人還是比較喜歡這種手寫sql語句的框架。

　　Dapper 雖然已經非常簡單，但是為了調用時方便還是進行了一下封裝 ，這樣在寫DAL 層方法時，就不用每次都try catch了。

　　2.先放代碼：

　　調用方法示例：

        #region role  增刪改查
        /// <summary>
        /// 增加一條
        /// </summary>
        public static void AddRole(Role role, IDbTransaction tran = null)
        {
            string sql = @"insert into role(Id,Name,Note)
                       values(@Id,@Name,@Note)";
            role.EnsureIdNotNull();
            DB.DBHelper.Execute(sql, role, tran);
        }

        /// <summary>
        /// 更新 
        /// </summary>
        public static void UpdateRole(Role role, IDbTransaction tran = null)
        {
            string sql = @"update role set Name=@Name,Note=@Note where Id=@Id";
            DB.DBHelper.Execute(sql, role, tran);
        }

        /// <summary>
        /// 刪除 一條記錄
        /// </summary>
        public static void DeleteRole(string Id, IDbTransaction tran = null)
        {
            string sql = "select count(1) from userrole where RoleId= @Id";
            var c = DB.DBHelper.ExecuteScalar<int>(sql, new { Id = @Id });
            if (c > 0)
            {
                throw new OperateException("該角色已經有用戶在使用，不能刪除");
            }

            List<string> sqllist = new List<string>();
            sqllist.Add("delete from role where Id=@Id");
            sqllist.Add("delete from rolemenu where RoleId=@Id"); //同步刪除為角色分配的權限
            DB.DBHelper.Execute(sqllist, new { Id = Id }, tran);
        }

        /// <summary>
        /// 列表查詢
        /// </summary>
        /// <param name="pl"></param>
        /// <returns></returns>
        public static ResultSet<Role> GetRoleList(ParamList pl)
        {
            string sql = @"select  Id,Name,Note from role where 1=1";
            pl.orderby = "Name";
            //添加各種查詢條件
            if (pl.isnotnull("keywords"))
            {
                sql += " and instr(concat(Name,Note),@keywords)>0";
            }
            return DB.DBHelper.GetResultSet<Role>(sql, pl.orderby, pl);
        }
        #endregion

 

DBHelper 類:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Configuration;
using System.Data;
using Dapper;
using CommonModel;

namespace DBTools
{
    /// <summary>
    /// 執行sql ，拋出異常
    /// </summary>
    public class DBHelper
    {
        #region 連接信息
        public virtual string ConnectionString
        {
            get;
            set;
        }
        public virtual DataBaseType DBType
        {
            get;
            set;
        }
        #endregion

        #region 獲取DBAdapter
        public DBAdapter GetDBAdapter()
        {
            return DBTools.DBFactory.GetAdapter(DBType, ConnectionString);
        }

        #endregion

        #region 查詢
        public List<dynamic> Query(string sql, object query = null, IDbTransaction tran = null)
        {
            DBAdapter adapter = null; ;

            try
            {
                if (tran == null)
                {
                    adapter = GetDBAdapter();
                }
                var conn = tran != null ? tran.Connection : adapter.OpenDatabase();
                var m = conn.Query(sql, query).ToList();
                return m;
            }
            catch (Exception ex) { throw ex; }
            finally
            {
                if (adapter != null)
                {
                    adapter.CloseDatabase();
                }
            }
        }

        public List<T> Query<T>(string sql, object query = null, IDbTransaction tran = null)
        {
            DBAdapter adapter = null; ;

            try
            {
                if (tran == null)
                {
                    adapter = GetDBAdapter();
                }
                var conn = tran != null ? tran.Connection : adapter.OpenDatabase();
                var m = conn.Query<T>(sql, query).ToList<T>();
                return m;
            }
            catch (Exception ex) { throw ex; }
            finally
            {
                if (adapter != null)
                {
                    adapter.CloseDatabase();
                }
            }
        }

        public T ExecuteScalar<T>(string sql, object query = null, IDbTransaction tran = null)
        {
            DBAdapter adapter = null; ;

            try
            {
                if (tran == null)
                {
                    adapter = GetDBAdapter();
                }
                var conn = tran != null ? tran.Connection : adapter.OpenDatabase();
                var m = conn.ExecuteScalar<T>(sql, query, tran);
                return m;
            }
            catch (Exception ex) { throw ex; }
            finally
            {
                if (adapter != null)
                {
                    adapter.CloseDatabase();
                }
            }
        }

        #endregion

        #region Result

        /// <summary>
        /// 返回一個ResultSet  查詢
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="sql"></param>
        /// <param name="pl"></param>
        /// <param name="tran"></param>
        /// <returns></returns>
        public ResultSet<T> GetResultSet<T>(string sql, string OrderBy, ParamList pl, IDbTransaction tran = null)
        {
            DBAdapter adapter = GetDBAdapter();

            try
            {
                var conn = adapter.OpenDatabase();
                if (pl.ispage)
                {
                    string pagesql = adapter.GetPageSql(sql, OrderBy);
                    string countsql = adapter.GetCountSql(sql);

                    var m = conn.Query<T>(pagesql, pl.GetParameters(), tran).ToList<T>();
                    var c = conn.ExecuteScalar<int>(countsql, pl.GetParameters(), tran);
                    return new ResultSet<T>() { Value = m, Total = c };
                }
                else
                {
                    var m = conn.Query<T>(sql + " order by " + OrderBy, pl.GetParameters(), tran).ToList<T>();
                    return new ResultSet<T>() { Value = m, Total = m.Count };
                }
            }
            catch
            {
                throw;
            }
            finally
            {
                adapter.CloseDatabase();
            }
        }

        /// <summary>
        /// 返回一個ResultSet  查詢
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="OrderBy"></param>
        /// <param name="pl"></param>
        /// <param name="tran"></param>
        /// <returns></returns>
        public ResultSet GetResultSet(string sql, string OrderBy, ParamList pl, IDbTransaction tran = null)
        {
            DBAdapter adapter = GetDBAdapter();

            try
            {
                var conn = adapter.OpenDatabase();
                if (pl.ispage)
                {
                    string pagesql = adapter.GetPageSql(sql, OrderBy);
                    string countsql = adapter.GetCountSql(sql);

                    var m = conn.Query(pagesql, pl.GetParameters(), tran);
                    var c = conn.ExecuteScalar<int>(countsql, pl.GetParameters(), tran);
                    return ResultSet.GetResultSet(m, c);
                }
                else
                {
                    var m = conn.Query(sql + " order by " + OrderBy, pl.GetParameters(), tran);
                    return ResultSet.GetResultSet(m);
                }
            }
            catch
            {
                throw;
            }
            finally
            {
                adapter.CloseDatabase();
            }
        }
        #endregion

        #region 執行sql
        /// <summary>
        /// 執行sql，返回受影響記錄數
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="model"></param>
        /// <param name="tran"></param>
        public int Execute(string sql, object model = null, IDbTransaction tran = null)
        {
            DBAdapter adapter = null; ;

            try
            {
                if (tran == null)
                {
                    adapter = GetDBAdapter();
                }
                var conn = tran != null ? tran.Connection : adapter.OpenDatabase();
                return conn.Execute(sql, model, tran);

            }
            catch (Exception ex) { throw ex; }
            finally
            {
                if (adapter != null)
                {
                    adapter.CloseDatabase();
                }
            }
        }
        /// <summary>
        /// 執行sql，返回受影響條記錄數
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="pl"></param>
        /// <param name="tran"></param>
        /// <returns></returns>
        public int Execute(string sql, ParamList pl, IDbTransaction tran = null)
        {
            DBAdapter adapter = null; ;

            try
            {
                if (tran == null)
                {
                    adapter = GetDBAdapter();
                }
                var conn = tran != null ? tran.Connection : adapter.OpenDatabase();
                return conn.Execute(sql, pl.GetParameters(), tran);

            }
            catch { throw; }
            finally
            {
                if (adapter != null)
                {
                    adapter.CloseDatabase();
                }
            }
        }




        /// <summary>
        /// 同一個sql語句，批量操作多個對象
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="models"></param>
        /// <param name="tran"></param>
        public int Execute(string sql, IEnumerable<object> models, IDbTransaction tran = null)
        {
            DBAdapter adapter = null; ;

            try
            {
                if (tran == null)
                {
                    adapter = GetDBAdapter();
                }
                var conn = tran != null ? tran.Connection : adapter.OpenDatabase();
                return conn.Execute(sql, models, tran);
            }
            catch (Exception ex) { throw ex; }
            finally
            {
                if (adapter != null)
                {
                    adapter.CloseDatabase();
                }
            }
        }

        /// <summary>
        /// 使用事務批量執行多個語句
        /// </summary>
        /// <param name="sqllist"></param>
        /// <param name="pl"></param>
        /// <returns></returns>
        public void Execute(List<string> sqllist, object model = null, IDbTransaction tran = null)
        {
            DBAdapter adapter = null; ;

            try
            {
                if (tran == null)
                {
                    adapter = GetDBAdapter();
                    tran = adapter.BeginTransaction();
                }
                var conn = tran.Connection;

                foreach (var sql in sqllist)
                {
                    conn.Execute(sql, model, tran);
                }
                if (adapter != null)
                {
                    adapter.Commit();
                }
            }
            catch
            {
                if (adapter != null)
                {
                    adapter.Rollback();
                }
                throw;
            }
            finally
            {
                if (adapter != null)
                {
                    adapter.CloseDatabase();
                }
            }

        }
        /// <summary>
        /// 使用事務批量執行sql語句
        /// </summary>
        /// <param name="sqllist"></param>
        /// <param name="pl"></param>
        /// <param name="tran"></param>
        public void Execute(List<string> sqllist, ParamList pl, IDbTransaction tran = null)
        {
            DBAdapter adapter = null; ;

            try
            {
                if (tran == null)
                {
                    adapter = GetDBAdapter();
                    tran = adapter.BeginTransaction();
                }
                var conn = tran.Connection;

                foreach (var sql in sqllist)
                {
                    conn.Execute(sql, pl.GetParameters(), tran);
                }
                if (adapter != null)
                {
                    adapter.Commit();
                }
            }
            catch
            {
                if (adapter != null)
                {
                    adapter.Rollback();
                }
                throw;
            }
            finally
            {
                if (adapter != null)
                {
                    adapter.CloseDatabase();
                }
            }

        }
        #endregion

    }
}

     3.說明：

　　　　Dapper 相關目錄結構如下：

　　　　

　　　　a.分成兩個項目是為了避免數據庫訪問DBTools 被每層引用。除DAL層外，各層可以只引用CommonModel 就可以了.

　　　　b.使用DBAdapter 和DBFactory 對相關操作進行了封裝，用於支持多數據庫，目前我已經實現了MySqlDBAdapter,其他的數據庫可以自行實現。

　　　　c. 使用時可以使用一個新的DB 類 對DBHelper 進行封裝，達到方便調用，及同一個項目中使用多個數據庫的目的，如在DAL 層中定義一個DB 類，類中包含一個靜態DBHelper 對象，這樣就可以向文中開始的那樣調用DBHelper 了。

　　　　如下：

　　　　　　

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Configuration;

namespace MVC.DAL
{
    public class DB 
    {
        private static DBTools.DBHelper _instance;
        private static object lockhelper = new object();
        public static DBTools.DBHelper DBHelper
        {
            get
            {
                if (_instance == null)
                {
                    lock (lockhelper)
                    {
                        if (_instance == null)
                        {
                            _instance = new DBTools.DBHelper();
                            _instance.DBType = DBTools.DataBaseType.MySql;
                            _instance.ConnectionString = ConfigurationManager.ConnectionStrings["mysql"].ConnectionString;
                        }
                    }
                }
                return _instance;
            }
        }
    }
}