SQL基本操作(示例代码)

 

using System;
using System.Collections;
using System.Collections.Specialized;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;

namespace SQLServerDAL //可以修改成实际项目的命名空间名称
{
    /**//// <summary>
    /// Copyright (C) 2004-2008 LiTianPing 
    /// 数据访问基础类(基于SQLServer)
    /// 用户可以修改满足自己项目的需要。
    /// </summary>
    public abstract class DbHelperSQL
    {
        //数据库连接字符串(web.config来配置)
        //<add key="ConnectionString" value="server=127.0.0.1;database=DATABASE;uid=sa;pwd=" />        
        protected static string connectionString = ConfigurationSettings.AppSettings["ConnectionString"];
        public DbHelperSQL()
        {            
        }

        公用方法#region 公用方法

        public static int GetMaxID(string FieldName,string TableName)
        {
            string strsql = "select max(" + FieldName + ")+1 from " + TableName;
            object obj = GetSingle(strsql);
            if (obj == null)
            {
                return 1;
            }
            else
            {
                return int.Parse(obj.ToString());
            }
        }
        public static bool Exists(string strSql, params SqlParameter[] cmdParms)
        {
            object obj = GetSingle(strSql, cmdParms);
            int cmdresult;
            if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
            {
                cmdresult = 0;
            }
            else
            {
                cmdresult = int.Parse(obj.ToString());
            }
            if (cmdresult == 0)
            {
                return false;
            }
            else
            {
                return true;
            }
        }
        #endregion

        执行简单SQL语句#region  执行简单SQL语句

        /**//// <summary>
        /// 执行SQL语句，返回影响的记录数
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <returns>影响的记录数</returns>
        public static int ExecuteSql(string SQLString)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {                
                using (SqlCommand cmd = new SqlCommand(SQLString,connection))
                {
                    try
                    {        
                        connection.Open();
                        int rows=cmd.ExecuteNonQuery();
                        return rows;
                    }
                    catch(System.Data.SqlClient.SqlException E)
                    {                    
                        connection.Close();
                        throw new Exception(E.Message);
                    }
                }                
            }
        }
        
        /**//// <summary>
        /// 执行多条SQL语句，实现数据库事务。
        /// </summary>
        /// <param name="SQLStringList">多条SQL语句</param>        
        public static void ExecuteSqlTran(ArrayList SQLStringList)
        {
            using (SqlConnection conn = new SqlConnection(connectionString))
            {
                conn.Open();
                SqlCommand cmd = new SqlCommand();
                cmd.Connection=conn;                
                SqlTransaction tx=conn.BeginTransaction();            
                cmd.Transaction=tx;                
                try
                {           
                    for(int n=0;n<SQLStringList.Count;n++)
                    {
                        string strsql=SQLStringList[n].ToString();
                        if (strsql.Trim().Length>1)
                        {
                            cmd.CommandText=strsql;
                            cmd.ExecuteNonQuery();
                        }
                    }                                        
                    tx.Commit();                    
                }
                catch(System.Data.SqlClient.SqlException E)
                {        
                    tx.Rollback();
                    throw new Exception(E.Message);
                }
            }
        }
        /**//// <summary>
        /// 执行带一个存储过程参数的的SQL语句。
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <param name="content">参数内容,比如一个字段是格式复杂的文章，有特殊符号，可以通过这个方式添加</param>
        /// <returns>影响的记录数</returns>
        public static int ExecuteSql(string SQLString,string content)
        {                
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                SqlCommand cmd = new SqlCommand(SQLString,connection);        
                System.Data.SqlClient.SqlParameter  myParameter = new System.Data.SqlClient.SqlParameter ( "@content", SqlDbType.NText);
                myParameter.Value = content ;
                cmd.Parameters.Add(myParameter);
                try
                {
                    connection.Open();
                    int rows=cmd.ExecuteNonQuery();
                    return rows;
                }
                catch(System.Data.SqlClient.SqlException E)
                {                
                    throw new Exception(E.Message);
                }
                finally
                {
                    cmd.Dispose();
                    connection.Close();
                }    
            }
        }        
        /**//// <summary>
        /// 向数据库里插入图像格式的字段(和上面情况类似的另一种实例)
        /// </summary>
        /// <param name="strSQL">SQL语句</param>
        /// <param name="fs">图像字节,数据库的字段类型为image的情况</param>
        /// <returns>影响的记录数</returns>
        public static int ExecuteSqlInsertImg(string strSQL,byte[] fs)
        {        
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                SqlCommand cmd = new SqlCommand(strSQL,connection);    
                System.Data.SqlClient.SqlParameter  myParameter = new System.Data.SqlClient.SqlParameter ( "@fs", SqlDbType.Image);
                myParameter.Value = fs ;
                cmd.Parameters.Add(myParameter);
                try
                {
                    connection.Open();
                    int rows=cmd.ExecuteNonQuery();
                    return rows;
                }
                catch(System.Data.SqlClient.SqlException E)
                {                
                    throw new Exception(E.Message);
                }
                finally
                {
                    cmd.Dispose();
                    connection.Close();
                }                
            }
        }
        
        /**//// <summary>
        /// 执行一条计算查询结果语句，返回查询结果（object）。
        /// </summary>
        /// <param name="SQLString">计算查询结果语句</param>
        /// <returns>查询结果（object）</returns>
        public static object GetSingle(string SQLString)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                using(SqlCommand cmd = new SqlCommand(SQLString,connection))
                {
                    try
                    {
                        connection.Open();
                        object obj = cmd.ExecuteScalar();
                        if((Object.Equals(obj,null))||(Object.Equals(obj,System.DBNull.Value)))
                        {                    
                            return null;
                        }
                        else
                        {
                            return obj;
                        }                
                    }
                    catch(System.Data.SqlClient.SqlException e)
                    {                        
                        connection.Close();
                        throw new Exception(e.Message);
                    }    
                }
            }
        }
        /**//// <summary>
        /// 执行查询语句，返回SqlDataReader
        /// </summary>
        /// <param name="strSQL">查询语句</param>
        /// <returns>SqlDataReader</returns>
        public static SqlDataReader ExecuteReader(string strSQL)
        {
            SqlConnection connection = new SqlConnection(connectionString);            
            SqlCommand cmd = new SqlCommand(strSQL,connection);                
            try
            {
                connection.Open();    
                SqlDataReader myReader = cmd.ExecuteReader();
                return myReader;
            }
            catch(System.Data.SqlClient.SqlException e)
            {                                
                throw new Exception(e.Message);
            }            
            
        }        
        /**//// <summary>
        /// 执行查询语句，返回DataSet
        /// </summary>
        /// <param name="SQLString">查询语句</param>
        /// <returns>DataSet</returns>
        public static DataSet Query(string SQLString)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                DataSet ds = new DataSet();
                try
                {
                    connection.Open();
                    SqlDataAdapter command = new SqlDataAdapter(SQLString,connection);                
                    command.Fill(ds,"ds");
                }
                catch(System.Data.SqlClient.SqlException ex)
                {                
                    throw new Exception(ex.Message);
                }            
                return ds;
            }            
        }


        #endregion

        执行带参数的SQL语句#region 执行带参数的SQL语句

        /**//// <summary>
        /// 执行SQL语句，返回影响的记录数
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <returns>影响的记录数</returns>
        public static int ExecuteSql(string SQLString,params SqlParameter[] cmdParms)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {                
                using (SqlCommand cmd = new SqlCommand())
                {
                    try
                    {        
                        PrepareCommand(cmd, connection, null,SQLString, cmdParms);
                        int rows=cmd.ExecuteNonQuery();
                        cmd.Parameters.Clear();
                        return rows;
                    }
                    catch(System.Data.SqlClient.SqlException E)
                    {                
                        throw new Exception(E.Message);
                    }
                }                
            }
        }
        
            
        /**//// <summary>
        /// 执行多条SQL语句，实现数据库事务。
        /// </summary>
        /// <param name="SQLStringList">SQL语句的哈希表（key为sql语句，value是该语句的SqlParameter[]）</param>
        public static void ExecuteSqlTran(Hashtable SQLStringList)
        {            
            using (SqlConnection conn = new SqlConnection(connectionString))
            {
                conn.Open();
                using (SqlTransaction trans = conn.BeginTransaction()) 
                {
                    SqlCommand cmd = new SqlCommand();
                    try 
                    {
                        //循环
                        foreach (DictionaryEntry myDE in SQLStringList)
                        {    
                            string     cmdText=myDE.Key.ToString();
                            SqlParameter[] cmdParms=(SqlParameter[])myDE.Value;
                            PrepareCommand(cmd,conn,trans,cmdText, cmdParms);
                            int val = cmd.ExecuteNonQuery();
                            cmd.Parameters.Clear();

                            trans.Commit();
                        }                    
                    }
                    catch 
                    {
                        trans.Rollback();
                        throw;
                    }
                }                
            }
        }
    
                
        /**//// <summary>
        /// 执行一条计算查询结果语句，返回查询结果（object）。
        /// </summary>
        /// <param name="SQLString">计算查询结果语句</param>
        /// <returns>查询结果（object）</returns>
        public static object GetSingle(string SQLString,params SqlParameter[] cmdParms)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                using (SqlCommand cmd = new SqlCommand())
                {
                    try
                    {
                        PrepareCommand(cmd, connection, null,SQLString, cmdParms);
                        object obj = cmd.ExecuteScalar();
                        cmd.Parameters.Clear();
                        if((Object.Equals(obj,null))||(Object.Equals(obj,System.DBNull.Value)))
                        {                    
                            return null;
                        }
                        else
                        {
                            return obj;
                        }                
                    }
                    catch(System.Data.SqlClient.SqlException e)
                    {                
                        throw new Exception(e.Message);
                    }                    
                }
            }
        }
        
        /**//// <summary>
        /// 执行查询语句，返回SqlDataReader
        /// </summary>
        /// <param name="strSQL">查询语句</param>
        /// <returns>SqlDataReader</returns>
        public static SqlDataReader ExecuteReader(string SQLString,params SqlParameter[] cmdParms)
        {        
            SqlConnection connection = new SqlConnection(connectionString);
            SqlCommand cmd = new SqlCommand();                
            try
            {
                PrepareCommand(cmd, connection, null,SQLString, cmdParms);
                SqlDataReader myReader = cmd.ExecuteReader();
                cmd.Parameters.Clear();
                return myReader;
            }
            catch(System.Data.SqlClient.SqlException e)
            {                                
                throw new Exception(e.Message);
            }                    
            
        }        
        
        /**//// <summary>
        /// 执行查询语句，返回DataSet
        /// </summary>
        /// <param name="SQLString">查询语句</param>
        /// <returns>DataSet</returns>
        public static DataSet Query(string SQLString,params SqlParameter[] cmdParms)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                SqlCommand cmd = new SqlCommand();
                PrepareCommand(cmd, connection, null,SQLString, cmdParms);
                using( SqlDataAdapter da = new SqlDataAdapter(cmd) )
                {
                    DataSet ds = new DataSet();    
                    try
                    {                                                
                        da.Fill(ds,"ds");
                        cmd.Parameters.Clear();
                    }
                    catch(System.Data.SqlClient.SqlException ex)
                    {                
                        throw new Exception(ex.Message);
                    }            
                    return ds;
                }                
            }            
        }


        private static void PrepareCommand(SqlCommand cmd,SqlConnection conn,SqlTransaction trans, string cmdText, SqlParameter[] cmdParms) 
        {
            if (conn.State != ConnectionState.Open)
                conn.Open();
            cmd.Connection = conn;
            cmd.CommandText = cmdText;
            if (trans != null)
                cmd.Transaction = trans;
            cmd.CommandType = CommandType.Text;//cmdType;
            if (cmdParms != null) 
            {
                foreach (SqlParameter parm in cmdParms)
                    cmd.Parameters.Add(parm);
            }
        }

        #endregion

        存储过程操作#region 存储过程操作

        /**//// <summary>
        /// 执行存储过程
        /// </summary>
        /// <param name="storedProcName">存储过程名</param>
        /// <param name="parameters">存储过程参数</param>
        /// <returns>SqlDataReader</returns>
        public static SqlDataReader RunProcedure(string storedProcName, IDataParameter[] parameters )
        {
            SqlConnection connection = new SqlConnection(connectionString);
            SqlDataReader returnReader;
            connection.Open();
            SqlCommand command = BuildQueryCommand( connection,storedProcName, parameters );
            command.CommandType = CommandType.StoredProcedure;
            returnReader = command.ExecuteReader();                
            return returnReader;            
        }
        
        
        /**//// <summary>
        /// 执行存储过程
        /// </summary>
        /// <param name="storedProcName">存储过程名</param>
        /// <param name="parameters">存储过程参数</param>
        /// <param name="tableName">DataSet结果中的表名</param>
        /// <returns>DataSet</returns>
        public static DataSet RunProcedure(string storedProcName, IDataParameter[] parameters, string tableName )
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                DataSet dataSet = new DataSet();
                connection.Open();
                SqlDataAdapter sqlDA = new SqlDataAdapter();
                sqlDA.SelectCommand = BuildQueryCommand(connection, storedProcName, parameters );
                sqlDA.Fill( dataSet, tableName );
                connection.Close();
                return dataSet;
            }
        }

        
        /**//// <summary>
        /// 构建 SqlCommand 对象(用来返回一个结果集，而不是一个整数值)
        /// </summary>
        /// <param name="connection">数据库连接</param>
        /// <param name="storedProcName">存储过程名</param>
        /// <param name="parameters">存储过程参数</param>
        /// <returns>SqlCommand</returns>
        private static SqlCommand BuildQueryCommand(SqlConnection connection,string storedProcName, IDataParameter[] parameters)
        {            
            SqlCommand command = new SqlCommand( storedProcName, connection );
            command.CommandType = CommandType.StoredProcedure;
            foreach (SqlParameter parameter in parameters)
            {
                command.Parameters.Add( parameter );
            }
            return command;            
        }
        
        /**//// <summary>
        /// 执行存储过程，返回影响的行数        
        /// </summary>
        /// <param name="storedProcName">存储过程名</param>
        /// <param name="parameters">存储过程参数</param>
        /// <param name="rowsAffected">影响的行数</param>
        /// <returns></returns>
        public static int RunProcedure(string storedProcName, IDataParameter[] parameters, out int rowsAffected )
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                int result;
                connection.Open();
                SqlCommand command = BuildIntCommand(connection,storedProcName, parameters );
                rowsAffected = command.ExecuteNonQuery();
                result = (int)command.Parameters["ReturnValue"].Value;
                //Connection.Close();
                return result;
            }
        }
        
        /**//// <summary>
        /// 创建 SqlCommand 对象实例(用来返回一个整数值)    
        /// </summary>
        /// <param name="storedProcName">存储过程名</param>
        /// <param name="parameters">存储过程参数</param>
        /// <returns>SqlCommand 对象实例</returns>
        private static SqlCommand BuildIntCommand(SqlConnection connection,string storedProcName, IDataParameter[] parameters)
        {
            SqlCommand command = BuildQueryCommand(connection,storedProcName, parameters );
            command.Parameters.Add( new SqlParameter ( "ReturnValue",
                SqlDbType.Int,4,ParameterDirection.ReturnValue,
                false,0,0,string.Empty,DataRowVersion.Default,null ));
            return command;
        }
        #endregion    

    }
}

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