1       大概思路

备注：黄色为影响参数

2       PetShop4的经典数据库连接代码回顾

PetShop4有3个函数，具体有：

ExecuteReader:可以读一个表的记录，只能读不能写。

ExecuteScalar:只能读一条记录，一般用来判断数据库是否有数据等，只能读不能写。

ExecuteNonQuery:可以写以可以读。

这里介绍一下PrepareCommand、ExecuteNoQuery。

2.1   PrepareCommand

注意：当前函数是private的，不提供给外部调用。

        /// <summary>        /// Internal function to prepare a command for execution by the database        /// </summary>        /// <param name="cmd">Existing command object</param>        /// <param name="conn">Database connection object</param>        /// <param name="trans">Optional transaction object</param>        /// <param name="cmdType">Command type, e.g. stored procedure</param>        /// <param name="cmdText">Command test</param>        /// <param name="commandParameters">Parameters for the command</param>        private static void PrepareCommand(OracleCommand cmd, OracleConnection conn, OracleTransaction trans, CommandType cmdType, string cmdText, OracleParameter[] commandParameters) {            //Open the connection if required            if (conn.State != ConnectionState.Open)                conn.Open();            //Set up the command            cmd.Connection = conn;            cmd.CommandText = cmdText;            cmd.CommandType = cmdType;            //Bind it to the transaction if it exists            if (trans != null)                cmd.Transaction = trans;            // Bind the parameters passed in            if (commandParameters != null) {                foreach (OracleParameter parm in commandParameters)                    cmd.Parameters.Add(parm);            }        }

2.2   ExecuteNoQuery

此函数：传入连接串、执行类型、SQL、参数

       /// <summary>        /// Execute a database query which does not include a select        /// </summary>        /// <param name="connString">Connection string to database</param>        /// <param name="cmdType">Command type either stored procedure or SQL</param>        /// <param name="cmdText">Acutall SQL Command</param>        /// <param name="commandParameters">Parameters to bind to the command</param>        /// <returns></returns>        public static int ExecuteNonQuery(string connectionString, CommandType cmdType, string cmdText, params OracleParameter[] commandParameters) {            // Create a new Oracle command            OracleCommand cmd = new OracleCommand();            //Create a connection            using (OracleConnection connection = new OracleConnection(connectionString)) {                //Prepare the command                PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);                //Execute the command                int val = cmd.ExecuteNonQuery();                cmd.Parameters.Clear();                return val;            }        }

此函数：传入事务、执行类型、SQL、参数

      /// <summary>        /// Execute an OracleCommand (that returns no resultset) against an existing database transaction        /// using the provided parameters.        /// </summary>        /// <remarks>        /// e.g.:         ///  int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "PublishOrders", new OracleParameter(":prodid", 24));        /// </remarks>        /// <param name="trans">an existing database transaction</param>        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>        /// <param name="commandText">the stored procedure name or PL/SQL command</param>        /// <param name="commandParameters">an array of OracleParamters used to execute the command</param>        /// <returns>an int representing the number of rows affected by the command</returns>        public static int ExecuteNonQuery(OracleTransaction trans, CommandType cmdType, string cmdText, params OracleParameter[] commandParameters) {            OracleCommand cmd = new OracleCommand();            PrepareCommand(cmd, trans.Connection, trans, cmdType, cmdText, commandParameters);            int val = cmd.ExecuteNonQuery();            cmd.Parameters.Clear();            return val;        }

此函数：传入连接、执行类型、SQL、参数

       /// <summary>        /// Execute an OracleCommand (that returns no resultset) against an existing database connection        /// using the provided parameters.        /// </summary>        /// <remarks>        /// e.g.:         ///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new OracleParameter(":prodid", 24));        /// </remarks>        /// <param name="conn">an existing database connection</param>        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>        /// <param name="commandText">the stored procedure name or PL/SQL command</param>        /// <param name="commandParameters">an array of OracleParamters used to execute the command</param>        /// <returns>an int representing the number of rows affected by the command</returns>        public static int ExecuteNonQuery(OracleConnection connection, CommandType cmdType, string cmdText, params OracleParameter[] commandParameters) {            OracleCommand cmd = new OracleCommand();            PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);            int val = cmd.ExecuteNonQuery();            cmd.Parameters.Clear();            return val;        }

3       如何写好一个的OracleHelper

3.1   PetShop的OracleHelper

PetShop不是写好了吗？为什么还要自己写？

eg:PetShop4的函数不足以方便我们操作数据库，如批量插入需要防注入的参数时，需要等全部插入完再提交整个事务。

eg:PetShop4的函数在处理存储过程里还不完善，返回值没有指向。

3.2   OracleHelper

注意：PetShop4在参数上在调用OracleHelper考虑了缓存，这里暂时不考虑。

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Data;using System.Data.OracleClient;using System.Collections;namespace Util{    public abstract class OracleHelper    {        /// <summary>        /// 准备存储过程执行查询        /// </summary>                /// <param name="connectionString">数据库连接</param>        public static OracleTransaction GetTrans(string connectionString)        {            OracleConnection conn = new OracleConnection(connectionString);            conn.Open();            OracleTransaction trans = conn.BeginTransaction();            return trans;        }        /// <summary>        /// 返回视图        /// </summary>        /// <param name="cmdType"></param>        /// <param name="cmdText"></param>        /// <param name="commandParameters"></param>        /// <returns></returns>        public static DataView ExecuteView(String connectionString, CommandType cmdType, string cmdText, params OracleParameter[] commandParameters)        {            OracleCommand cmd = new OracleCommand();            using (OracleConnection conn = new OracleConnection(connectionString))            {                PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);                DataSet ds = new DataSet();                OracleDataAdapter da = new OracleDataAdapter(cmd);                da.Fill(ds);                DataView dv = ds.Tables[0].DefaultView;                cmd.Parameters.Clear();                return dv;            }        }        /// <summary>        /// 执行并返回影响行数        /// </summary>        /// <param name="connectionString">连接字符串</param>        /// <param name="cmdType">执行类型</param>        /// <param name="cmdText">执行文本</param>        /// <param name="commandParameters">参数</param>        /// <returns></returns>        public static int ExecuteNonQuery(string connectionString, CommandType cmdType, string cmdText, IList commandParameters)        {            OracleCommand cmd = new OracleCommand();            using (OracleConnection connection = new OracleConnection(connectionString))            {                PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);                int val = cmd.ExecuteNonQuery();                cmd.Parameters.Clear();                return val;            }        }        /// <summary>        /// Execute a database query which does not include a select        /// </summary>        /// <param name="connString">Connection string to database</param>        /// <param name="cmdType">Command type either stored procedure or SQL</param>        /// <param name="cmdText">Acutall SQL Command</param>        /// <param name="commandParameters">Parameters to bind to the command</param>        /// <returns></returns>        public static int ExecuteNonQuery(string connectionString, CommandType cmdType, string cmdText, params OracleParameter[] commandParameters)        {            // Create a new Oracle command            OracleCommand cmd = new OracleCommand();            //Create a connection            using (OracleConnection connection = new OracleConnection(connectionString))            {                //Prepare the command                PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);                //Execute the command                int val = cmd.ExecuteNonQuery();                cmd.Parameters.Clear();                return val;            }        }        ///    <summary>        ///    Execute    a OracleCommand (that returns a 1x1 resultset)    against    the    specified SqlTransaction        ///    using the provided parameters.        ///    </summary>        ///    <param name="transaction">A    valid SqlTransaction</param>        ///    <param name="commandType">The CommandType (stored procedure, text, etc.)</param>        ///    <param name="commandText">The stored procedure name    or PL/SQL command</param>        ///    <param name="commandParameters">An array of    OracleParamters used to execute the command</param>        ///    <returns>An    object containing the value    in the 1x1 resultset generated by the command</returns>        public static int ExecuteNonQuery(OracleTransaction trans, CommandType cmdType, string cmdText, params OracleParameter[] commandParameters)        {            OracleCommand cmd = new OracleCommand();            PrepareCommand(cmd, trans.Connection, trans, cmdType, cmdText, commandParameters);            int val = cmd.ExecuteNonQuery();            cmd.Parameters.Clear();            return val;        }        /// <summary>        /// 执行并返回影响行数，得手动关闭数据库连接        /// </summary>        /// <param name="connection">连接字符串</param>        /// <param name="cmdType">执行类型</param>        /// <param name="cmdText">执行文本</param>        /// <param name="commandParameters">参数</param>        /// <returns></returns>        public static int ExecuteNonQuery(OracleConnection connection, CommandType cmdType, string cmdText, params OracleParameter[] commandParameters)        {            OracleCommand cmd = new OracleCommand();            PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);            int val = cmd.ExecuteNonQuery();            cmd.Parameters.Clear();            return val;        }        /// <summary>        /// Execute a select query that will return a result set        /// </summary>        /// <param name="connString">Connection string</param>        //// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>        /// <param name="commandText">the stored procedure name or PL/SQL command</param>        /// <param name="commandParameters">an array of OracleParamters used to execute the command</param>        /// <returns></returns>        public static OracleDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText, params OracleParameter[] commandParameters)        {            //Create the command and connection            OracleCommand cmd = new OracleCommand();            OracleConnection conn = new OracleConnection(connectionString);            try            {                //Prepare the command to execute                PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);                //Execute the query, stating that the connection should close when the resulting datareader has been read                OracleDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);                cmd.Parameters.Clear();                return rdr;            }            catch            {                //If an error occurs close the connection as the reader will not be used and we expect it to close the connection                conn.Close();                throw;            }        }        /// <summary>        /// Internal function to prepare a command for execution by the database        /// </summary>        /// <param name="cmd">Existing command object</param>        /// <param name="conn">Database connection object</param>        /// <param name="trans">Optional transaction object</param>        /// <param name="cmdType">Command type, e.g. stored procedure</param>        /// <param name="cmdText">Command test</param>        /// <param name="commandParameters">Parameters for the command</param>        private static void PrepareCommand(OracleCommand cmd, OracleConnection conn, OracleTransaction trans, CommandType cmdType, string cmdText, OracleParameter[] commandParameters)        {            //Open the connection if required            if (conn.State != ConnectionState.Open)                conn.Open();            //Set up the command            cmd.Connection = conn;            cmd.CommandText = cmdText;            cmd.CommandType = cmdType;            //Bind it to the transaction if it exists            if (trans != null)                cmd.Transaction = trans;            // Bind the parameters passed in            if (commandParameters != null)            {                // 若参数Value值为null时，插入到数据库的值应该为DBNull.Value，且为ParameterDirection.Input                foreach (OracleParameter parm in commandParameters)                    if (parm.Value == null && parm.Direction == ParameterDirection.Input)                    {                        cmd.Parameters.Add(parm.ParameterName, parm.OracleType, parm.Size).Value = DBNull.Value;                    }                    else                    {                        cmd.Parameters.Add(parm);                    }            }        }        /// <summary>        /// Internal function to prepare a command for execution by the database        /// </summary>        /// <param name="cmd">Existing command object</param>        /// <param name="conn">Database connection object</param>        /// <param name="trans">Optional transaction object</param>        /// <param name="cmdType">Command type, e.g. stored procedure</param>        /// <param name="cmdText">Command test</param>        /// <param name="commandParameters">Parameters for the command</param>        private static void PrepareCommand(OracleCommand cmd, OracleConnection conn, OracleTransaction trans, CommandType cmdType, string cmdText, IList commandParameters)        {            //Open the connection if required            if (conn.State != ConnectionState.Open)                conn.Open();            //Set up the command            cmd.Connection = conn;            cmd.CommandText = cmdText;            cmd.CommandType = cmdType;            //Bind it to the transaction if it exists            if (trans != null)                cmd.Transaction = trans;            // Bind the parameters passed in            if (commandParameters != null)            {                // 若参数Value值为null时，插入到数据库的值应该为DBNull.Value，且为ParameterDirection.Input                foreach (OracleParameter parm in commandParameters)                    if (parm.Value == null && parm.Direction == ParameterDirection.Input)                    {                        cmd.Parameters.Add(parm.ParameterName, parm.OracleType, parm.Size).Value = DBNull.Value;                    }                    else                    {                        cmd.Parameters.Add(parm);                    }            }        }    }}

4       代码示例

4.1   使用存储过程

      /// <summary>        /// 新增        /// </summary>        /// <param name="v_dept">实体</param>        /// <param name="re">返回ID</param>        /// <param name="msg">返回消息</param>        /// <returns></returns>        private void executeWithOracleTrans(DEPT v_dept, ref int re, ref string msg)        {            try            {                OracleParameter[] paras = new OracleParameter[5];                paras[0] = new OracleParameter("P_DEPTNO", OracleType.Number);                paras[0].Value = v_dept.DEPTNO;                paras[1] = new OracleParameter("P_DNAME", OracleType.VarChar);                paras[1].Value = v_dept.DNAME;                paras[2] = new OracleParameter("P_LOC", OracleType.VarChar);                paras[2].Value = v_dept.LOC;                paras[3] = new OracleParameter("X_RE", OracleType.Int32);                paras[3].Direction = ParameterDirection.Output;                paras[4] = new OracleParameter("X_MSG", OracleType.VarChar, 100);                paras[4].Direction = ParameterDirection.Output;                OracleHelper.ExecuteNonQuery(this.OracleConnectString, CommandType.StoredProcedure, "PKG_DEMO.Dept_Add", paras);                re = Convert.ToInt32(paras[3].Value);                msg = paras[4].Value.ToString();            }            catch (Exception ex)            {                re = 9;                msg = ex.Message;            }        }

4.2   批处理之使用PL/SQL

      /// <summary>        /// 用PL/SQL增加        /// </summary>        /// <param name="list_dept"></param>        /// <param name="re"></param>        /// <param name="msg"></param>        private void executeWithPLSQL(IList<DEPT> list_dept, ref int re, ref string msg)        {            string sql = string.Empty;            string insert_sql = string.Empty;            List<OracleParameter> list_parm = new List<OracleParameter>();            try            {                int i = 0;                foreach (DEPT v_dept in list_dept)                {                    insert_sql += "insert into DEPT (DEPTNO, DNAME, LOC) values(:P_DEPTNO" + i + ", :P_DNAME" + i + ", :P_LOC" + i + ");";                    OracleParameter[] paras = new OracleParameter[3];                    paras[0] = new OracleParameter("P_DEPTNO" + i, OracleType.Number);                    paras[0].Value = v_dept.DEPTNO;                    paras[1] = new OracleParameter("P_DNAME" + i, OracleType.VarChar);                    paras[1].Value = v_dept.DNAME;                    paras[2] = new OracleParameter("P_LOC" + i, OracleType.VarChar);                    paras[2].Value = v_dept.LOC;                    list_parm.Add(paras[0]);                    list_parm.Add(paras[1]);                    list_parm.Add(paras[2]);                    i++;                }                sql = "begin " +                    insert_sql +                  ":X_RE  := 1; " +                  ":X_MSG := '提示：新增成功!'; " +                  "commit; " +                "exception " +                  "when others then " +                    "rollback; " +                    ":X_RE  := 9; " +                    ":X_MSG := '操作失败:[' || sqlcode || ':' || sqlerrm || ']'; " +                "end; ";                OracleParameter x_re = new OracleParameter("X_RE", OracleType.Int32);                x_re.Direction = ParameterDirection.Output;                OracleParameter x_msg = new OracleParameter("X_MSG", OracleType.VarChar, 100);                x_msg.Direction = ParameterDirection.Output;                list_parm.Add(x_re);                list_parm.Add(x_msg);                 OracleHelper.ExecuteNonQuery(this.OracleConnectString, CommandType.Text, sql, list_parm);                re = Convert.ToInt32(x_re.Value);                msg = x_msg.Value.ToString();            }            catch (Exception ex)            {                re = 9;                msg = ex.Message;            }        }

4.3   批处理之使用事务

       /// <summary>        /// 用事务新增        /// </summary>        /// <param name="list_dept"></param>        /// <param name="re"></param>        /// <param name="msg"></param>        private void executeWithTrans(IList<DEPT> list_dept, ref int re, ref string msg)        {            // 启用事务进行控制            OracleTransaction myTrans = OracleHelper.GetTrans(this.OracleConnectString);            OracleConnection conn = myTrans.Connection;            try            {                string sql = string.Empty;                foreach (DEPT o in list_dept)                {                    sql = "insert into DEPT(DEPTNO,DNAME,LOC) values(:P_DEPTNO,:P_DNAME,:P_LOC)";                    OracleParameter[] paras = new OracleParameter[3];                    paras[0] = new OracleParameter("P_DEPTNO", OracleType.Int32);                    paras[0].Value = o.DEPTNO;                    paras[1] = new OracleParameter("P_DNAME", OracleType.VarChar);                    paras[1].Value = o.DNAME;                    paras[2] = new OracleParameter("P_LOC", OracleType.VarChar);                    paras[2].Value = o.LOC;                    OracleHelper.ExecuteNonQuery(myTrans, CommandType.Text, sql, paras);                }                myTrans.Commit();                re = 1;            }            catch (Exception ex)            {                myTrans.Rollback();                re = 9;                msg = ex.Message;            }            finally            {                conn.Close();            }        }

5       运行效果

6       小结

学好.Net，从PetShop开始。