SQLHelper用的不爽，试试CmdRunner吧

为了方便的在SQLConnection上执行sql，微软官方提供了开源数据库操作类：SQLHelper。

这玩意，有两个问题弄的很不爽：

1. 每次执行的时候要传递ConnectionString，参数传一大堆；如果一个处理过程要在同一连接上多次执行SQL，代码看着都不舒服

2. 每次用SQLHelper执行SQL时，都使用单独的连接，带连接上下文(#开头的)临时表不能用

SQLHelper不罗嗦了，微软的大牛们推出的，自然有好处，至少不用担心连接释放的问题。

此外，稍大点的项目估计大家也都封装个操作类，很少用SQLHelper吧。

在这里，贴出我实现的CmdRunner类：

using System;
using System.Collections.Generic;
using System.Text;
using System.Data.SqlClient;

namespace Yzj.CSharp.DBInterface.Connection
{
    /// <summary>
    /// 提供在同一连接上下文里多次执行SQL的服务
   /// 可使用连接上下文临时表
   /// 区别于SqlHelper执行时对链接不可控
   /// </summary>
    public class CmdRunner : System.IDisposable
    {
        int _sqlBulkCopySize = 10000;
        string _connString = string.Empty;
        SqlConnection _conn = null;

        public CmdRunner(string connectionString)
        {
            if (string.IsNullOrEmpty(connectionString))
                throw new System.ArgumentNullException();

            _connString = connectionString;
            _conn = new SqlConnection(connectionString);
            _conn.Open();
        }
        public SqlConnection Connection { get { return _conn; } }
        public int SqlBulkCopySize
        {
            get { return _sqlBulkCopySize; }
            set { _sqlBulkCopySize = value > 1 ? value : 10000; }
        }

        public int ExcuteNoQuery(string sql)
        {
            return ExcuteNoQuery(sql, 0, null);
        }
        public int ExcuteNoQuery(string sql, params SqlParameter[] array)
        {
            return ExcuteNoQuery(sql, 0, array);
        }
        public int ExcuteNoQuery(string sql, int iTimeOut, params SqlParameter[] array)
        {
            System.Diagnostics.Debug.Assert(_conn != null && _conn.State == System.Data.ConnectionState.Open);

            int nCount = 0;
            using (SqlCommand cmd = _conn.CreateCommand())
            {
                cmd.CommandText = sql;
                cmd.CommandTimeout = iTimeOut;
                if (array != null && array.Length > 0)
                {
                    cmd.Parameters.AddRange(array);
                }

                nCount = cmd.ExecuteNonQuery();
                cmd.Parameters.Clear();
            }

            return nCount;
        }

        public object ExecuteScalar(string sql)
        {
            return ExecuteScalar(sql, null);
        }
        public object ExecuteScalar(string sql, params SqlParameter[] array)
        {
            System.Diagnostics.Debug.Assert(_conn != null && _conn.State == System.Data.ConnectionState.Open);

            object value = null;
            using (SqlCommand cmd = _conn.CreateCommand())
            {
                cmd.CommandText = sql;
                cmd.CommandTimeout = 0;
                if (array != null && array.Length > 0)
                {
                    cmd.Parameters.AddRange(array);
                }

                value = cmd.ExecuteScalar();
                cmd.Parameters.Clear();
            }

            return value;
        }

        public System.Data.DataTable ExcuteDataTable(string sql)
        {
            return ExcuteDataTable(sql, null);
        }
        public System.Data.DataTable ExcuteDataTable(string sql, params SqlParameter[] array)
        {
            System.Diagnostics.Debug.Assert(_conn != null && _conn.State == System.Data.ConnectionState.Open);

            System.Data.DataTable dt = new System.Data.DataTable();
            using (SqlCommand cmd = _conn.CreateCommand())
            {
                cmd.CommandText = sql;
                cmd.CommandTimeout = 0;
                if (array != null && array.Length > 0)
                {
                    cmd.Parameters.AddRange(array);
                }

                using (SqlDataAdapter ad = new SqlDataAdapter(cmd))
                {
                    ad.Fill(dt);
                }

                cmd.Parameters.Clear();
            }

            return dt;
        }

        /// <summary>
        /// 以SqlBulkCopy的方式，将在sourceRunner中的sourceSql查询结果，按照desColumns的顺序插入到当前Runner的desTable表中
        /// </summary>
        /// <param name="sourceRunner">源数据库连接</param>
        /// <param name="sourceSql">取数据的源SQL</param>
        /// <param name="desTable">要插入的表</param>
        /// <param name="desColumns">要插入表的列，格式： "column1, column2, ……"</param>
        public void ExcuteSqlBulkCopy(SqlConnection sourceConn, string sourceSql, string desTable, string desColumns)
        {
            if (string.IsNullOrEmpty(desTable))
                throw new System.ArgumentNullException("desTable");

            if (string.IsNullOrEmpty(sourceSql))
                throw new System.ArgumentNullException("sourceSql");

            if (string.IsNullOrEmpty(desColumns))
                throw new System.ArgumentNullException("desColumns");

            using (SqlBulkCopy bulkCopy = new SqlBulkCopy(this._conn))
            {
                bulkCopy.BulkCopyTimeout = 1200;
                bulkCopy.BatchSize = SqlBulkCopySize;
                bulkCopy.DestinationTableName = desTable;

                string[] columns = desColumns.Split(',');
                for (int i = 0; i < columns.Length; i++)
                {
                    string dbColumn = this.GetDbColumn(desTable, columns[i].Trim());
                    bulkCopy.ColumnMappings.Add(i, dbColumn);
                }
                using (SqlCommand sourceCmd = sourceConn.CreateCommand())
                {
                    sourceCmd.CommandText = sourceSql;
                    sourceCmd.CommandTimeout = 90000;
                    using (SqlDataReader sourceReader = sourceCmd.ExecuteReader())
                    {
                        bulkCopy.WriteToServer(sourceReader);
                    }
                }
            }
        }
        public void ExcuteSqlBulkCopy(string sourceSql, string desTable, string desColumns)
        {
            using (CmdRunner runner = new CmdRunner(this._connString))
            {
                ExcuteSqlBulkCopy(runner.Connection, sourceSql, desTable, desColumns);
            }
        }
        #region sqlbulkcopy-column-manage
        Dictionary<string, string> _columnToDbColumn = new Dictionary<string, string>();
        /// <summary>
        /// 获取给定表给定列的数据库精确名称，返回的列和数据库定义保持大小写一致
        /// </summary>
        /// <param name="tableName">表名，可以是dbName..tableName、dbName.dbo.tableName、tableName三种形式之一</param>
        /// <param name="writeColumnName">列名，同通常SQL语句写法，不计大小写</param>
        /// <returns>返回对应的精确列名；如果未找到，会抛掷异常</returns>
        string GetDbColumn(string tableName, string writeColumnName)
        {
            if (string.IsNullOrEmpty(tableName)
                || string.IsNullOrEmpty(writeColumnName))
            {
                throw new System.InvalidOperationException();
            }

            // 查看缓存是否存在
            string key = tableName + "." + writeColumnName.ToLower();
            if (_columnToDbColumn.ContainsKey(key))
                return _columnToDbColumn[key];

            // 从数据库创建缓存
            // tableName 可以是：olap..tableName、olap.dbo.tableName、tableName三种形式
            string dbTable = tableName;
            string dbName = string.Empty;
            int nIndex = tableName.IndexOf('.');
            if (nIndex > 0)
            {
                dbName = tableName.Substring(0, nIndex) + "..";

                nIndex = tableName.LastIndexOf('.');
                dbTable = tableName.Substring(nIndex + 1);
            }

            string sql = string.Format("select name from {0}syscolumns where id=object_id('{1}')", dbName, dbTable);
            System.Data.DataTable dt = this.ExcuteDataTable(sql);
            if (dt.Rows.Count == 0)
                throw new System.Exception("不存在表'" + tableName + "'！");

            string dbColumn = string.Empty;
            List<string> dbColumns = new List<string>();
            foreach (System.Data.DataRow row in dt.Rows)
            {
                string column = Convert.ToString(row[0]);
                _columnToDbColumn[tableName + "." + column.ToLower()] = column;

                if (dbColumn.Length == 0 && column.Equals(writeColumnName, StringComparison.InvariantCultureIgnoreCase))
                    dbColumn = column;
            }

            if (dbColumn.Length == 0)
                throw new System.Exception("表'" + tableName + "'不存在列'" + writeColumnName + "'！");

            return dbColumn;
        }
        #endregion

        #region IDisposable 成员

        public void Dispose()
        {
            if (_conn != null)
            {
                _conn.Dispose();
                _conn = null;
            }
        }

        #endregion
    }
}

和SQLHelper的主要区别点：

1. CmdRunner对象组合SQLConnection，用完需要Disppose

2. 带SqlParameter[] 参数的，都给params化，调用的时候会少了new SqlParameter[]的代码

3. 封装SQLBulkCopy，批量数据插入，提高数据插入效率

欢迎发表看法，交流经验