C#--SQLserver、oracle、MySQL和Access的封装源码

抽象类：

using System;
using System.Collections.Generic;
using System.Data;  //DataSet引用集
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace AdoNet
{
    public abstract class Database
    {
        public abstract string Open(string link);                                   //打开
        public abstract string Insdelupd(string sql);                               //增删改
        public abstract string Insdelupd(string sql, string link);                  //增删改
        public abstract DataSet Select(string sql, out string record);              //查
        public abstract DataSet Select(string sql, string link, out string record); //查
        public abstract string Close();                                             //关闭
    }
}

SQLserver：

/*----------------------------------------------------------------
 * 
// author:HQ
 * 
// describe:SQLserver
 * 
// date:2019-10-08
 * 
------------------------------------------------------------------*/
using System;
using System.Collections.Generic;
using System.Data;              //DataSet引用集
using System.Data.SqlClient;    //sql引用集
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace AdoNet
{
    public class SQLserver : Database
    {
        private SqlConnection sql_con;  //声明对象

        /// <summary>
        /// SQLserver open
        /// </summary>
        /// <param name="link">link statement</param>
        /// <returns>Success:success; Fail:reason</returns>
        public override string Open(string link)
        {
            try
            {
                sql_con = new SqlConnection(link);
                sql_con.Open();
                return "success";
            }
            catch (Exception ex)
            {
                return ex.Message;
            }
        }

        /// <summary>
        /// SQLserver close
        /// </summary>
        /// <returns>Success:success Fail:reason</returns>
        public override string Close()
        {
            try
            {
                if (sql_con == null)
                {
                    return "No database connection";
                }
                if (sql_con.State == ConnectionState.Open || sql_con.State == ConnectionState.Connecting)
                {
                    sql_con.Close();
                    sql_con.Dispose();
                }
                else
                {
                    if (sql_con.State == ConnectionState.Closed)
                    {
                        return "success";
                    }
                    if (sql_con.State == ConnectionState.Broken)
                    {
                        return "ConnectionState:Broken";
                    }
                }
                return "success";
            }
            catch (Exception ex)
            {
                return ex.Message;
            }
        }

        /// <summary>
        /// SQLserver insert,delete,update
        /// </summary>
        /// <param name="sql">insert,delete,update statement</param>
        /// <returns>Success:success + Number of affected rows; Fail:reason</returns>
        public override string Insdelupd(string sql)
        {
            try
            {
                int num = 0;
                if (sql_con == null)
                {
                    return "Please open the database connection first";
                }
                if (sql_con.State == ConnectionState.Open)
                {
                    SqlCommand sqlCommand = new SqlCommand(sql, sql_con);
                    num = sqlCommand.ExecuteNonQuery();
                }
                else
                {
                    if (sql_con.State == ConnectionState.Closed)
                    {
                        return "Database connection closed";
                    }
                    if (sql_con.State == ConnectionState.Broken)
                    {
                        return "Database connection is destroyed";
                    }
                    if (sql_con.State == ConnectionState.Connecting)
                    {
                        return "The database is in connection";
                    }
                }
                return "success" + num;
            }
            catch (Exception ex)
            {
                return ex.Message.ToString();
            }
        }

        /// <summary>
        /// SQLserver insert,delete,update
        /// </summary>
        /// <param name="sql">insert,delete,update statement</param>
        /// <param name="link">link statement</param>
        /// <returns>Success:success + Number of affected rows; Fail:reason</returns>
        public override string Insdelupd(string sql, string link)
        {
            try
            {
                int num = 0;
                using (SqlConnection con = new SqlConnection(link))
                {
                    con.Open();
                    //操作数据库的工具SqlCommand
                    SqlCommand cmd = new SqlCommand(sql, con);  //操作语句和链接工具
                    num = cmd.ExecuteNonQuery();            //执行操作返回影响行数
                    con.Close();
                    return "success" + num;
                }
            }
            catch (Exception ex)
            {
                return ex.Message.ToString();
            }
        }

        /// <summary>
        /// SQLserver select
        /// </summary>
        /// <param name="sql">select statement</param>
        /// <param name="record">Success:success; Fail:reason</param>
        /// <returns>select result</returns>
        public override DataSet Select(string sql, out string record)
        {
            try
            {
                //储存数据的工具初始化
                DataSet dataSet = new DataSet();
                if (sql_con == null)
                {
                    record = "Please open the database connection first";
                    return dataSet;
                }
                if (sql_con.State == ConnectionState.Open)
                {
                    SqlDataAdapter sqlDataAdapter = new SqlDataAdapter(sql, sql_con);
                    sqlDataAdapter.Fill(dataSet, "sample");
                    sqlDataAdapter.Dispose();
                    record = "success";
                    return dataSet;
                }
                if (sql_con.State == ConnectionState.Closed)
                {
                    record = "Database connection closed";
                    return dataSet;
                }
                if (sql_con.State == ConnectionState.Broken)
                {
                    record = "Database connection is destroyed";
                    return dataSet;
                }
                if (sql_con.State == ConnectionState.Connecting)
                {
                    record = "The database is in connection";
                    return dataSet;
                }
                record = "ERROR";
                return dataSet;
            }
            catch (Exception ex)
            {
                DataSet dataSet = new DataSet();
                record = ex.Message.ToString();
                return dataSet;
            }
        }

        /// <summary>
        /// SQLserver select
        /// </summary>
        /// <param name="sql">select statement</param>
        /// <param name="link">link statement</param>
        /// <param name="record">Success:success; Fail:reason</param>
        /// <returns>select result</returns>
        public override DataSet Select(string sql, string link, out string record)
        {
            try
            {
                //储存数据的工具初始化
                DataSet ds = new DataSet();
                //相当于链接数据库的一个工具类（连接字符串）
                using (SqlConnection con = new SqlConnection(link))
                {
                    con.Open();                                         //打开
                    //用SqlConnection工具链接数据库，在通过sql查询语句查询结果现存入sql适配器
                    SqlDataAdapter sda = new SqlDataAdapter(sql, con);  //(查询语句和连接工具)
                    sda.Fill(ds, "sample");                             //将适配器数据存入DataSet工具中
                    con.Close();                                        //用完关闭SqlConnection工具
                    sda.Dispose();                                      //手动释放SqlDataAdapter
                    record = "success";
                    return ds;
                }
            }
            catch (Exception ex)
            {
                DataSet dataSet = new DataSet();
                record = ex.Message.ToString();
                return dataSet;
            }
        }
    }
}

Oracle：

/*----------------------------------------------------------------
 * 
// author:HQ
 * 
// describe:Oracle
 * 
// date:2019-10-08
 * 
------------------------------------------------------------------*/
using System;
using System.Collections.Generic;
using System.Data;              //DataSet引用集
using System.Data.OracleClient; //oracle引用
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace AdoNet
{
    public class Oracle : Database
    {
        private OracleConnection oracle_con;

        /// <summary>
        /// Oracle open
        /// </summary>
        /// <param name="link">link statement</param>
        /// <returns>Success:success; Fail:reason</returns>
        public override string Open(string link)
        {
            try
            {
                oracle_con = new OracleConnection(link);
                oracle_con.Open();
                return "success";
            }
            catch (Exception ex)
            {
                return ex.Message;
            }
        }

        /// <summary>
        /// Oracle close
        /// </summary>
        /// <returns>Success:success Fail:reason</returns>
        public override string Close()
        {
            try
            {
                if (oracle_con == null)
                {
                    return "No database connection";
                }
                if (oracle_con.State == ConnectionState.Open)
                {
                    oracle_con.Close();
                    oracle_con.Dispose();
                }
                else
                {
                    if (oracle_con.State == ConnectionState.Closed)
                    {
                        return "success";
                    }
                    if (oracle_con.State == ConnectionState.Broken)
                    {
                        return "ConnectionState:Broken";
                    }
                }
                return "success";
            }
            catch (Exception ex)
            {
                return ex.Message;
            }
        }

        /// <summary>
        /// Oracle insert,delete,update
        /// </summary>
        /// <param name="sql">insert,delete,update statement</param>
        /// <returns>Success:success + Number of affected rows; Fail:reason</returns>
        public override string Insdelupd(string sql)
        {
            try
            {
                int num = 0;
                if (oracle_con == null)
                {
                    return "Please open the database connection first";
                }
                if (oracle_con.State == ConnectionState.Open)
                {
                    OracleCommand oracleCommand = new OracleCommand(sql, oracle_con);
                    num = oracleCommand.ExecuteNonQuery();
                }
                else
                {
                    if (oracle_con.State == ConnectionState.Closed)
                    {
                        return "Database connection closed";
                    }
                    if (oracle_con.State == ConnectionState.Broken)
                    {
                        return "Database connection is destroyed";
                    }
                }
                return "success" + num;
            }
            catch (Exception ex)
            {
                return ex.Message.ToString();
            }
        }

        /// <summary>
        /// Oracle insert,delete,update
        /// </summary>
        /// <param name="sql">insert,delete,update statement</param>
        /// <param name="link">link statement</param>
        /// <returns>Success:success + Number of affected rows; Fail:reason</returns>
        public override string Insdelupd(string sql, string link)
        {
            try
            {
                int num = 0;
                using (OracleConnection oracleConnection = new OracleConnection(link))
                {
                    DataSet dataSet = new DataSet();
                    oracleConnection.Open();
                    OracleCommand oracleCommand = new OracleCommand(sql, oracleConnection);
                    num = oracleCommand.ExecuteNonQuery();
                    oracleConnection.Close();
                    return "success" + num;
                }
            }
            catch (Exception ex)
            {
                return ex.Message.ToString();
            }
        }

        /// <summary>
        /// Oracle select
        /// </summary>
        /// <param name="sql">select statement</param>
        /// <param name="record">Success:success; Fail:reason</param>
        /// <returns>select result</returns>
        public override DataSet Select(string sql, out string record)
        {
            try
            {
                DataSet dataSet = new DataSet();
                if (oracle_con != null)
                {
                    if (oracle_con.State == ConnectionState.Open)
                    {
                        OracleDataAdapter oracleDataAdapter = new OracleDataAdapter(sql, oracle_con);
                        oracleDataAdapter.Fill(dataSet, "sample");
                        oracleDataAdapter.Dispose();
                        record = "OK";
                        return dataSet;
                    }
                    if (oracle_con.State == ConnectionState.Closed)
                    {
                        record = "Database connection closed";
                    }
                    else if (oracle_con.State == ConnectionState.Broken)
                    {
                        record = "Database connection is destroyed";
                    }
                }
                else
                {
                    record = "Please open the database connection first";
                }
                record = "error";
                return dataSet;
            }
            catch (Exception ex)
            {
                DataSet dataSet = new DataSet();
                record = ex.Message.ToString();
                return dataSet;
            }
        }

        /// <summary>
        /// Oracle select
        /// </summary>
        /// <param name="sql">select statement</param>
        /// <param name="link">link statement</param>
        /// <param name="record">Success:success; Fail:reason</param>
        /// <returns>select result</returns>
        public override DataSet Select(string sql, string link, out string record)
        {
            try
            {
                using (OracleConnection oracleConnection = new OracleConnection(link))
                {
                    DataSet dataSet = new DataSet();
                    oracleConnection.Open();
                    OracleDataAdapter oracleDataAdapter = new OracleDataAdapter(sql, oracleConnection);
                    oracleDataAdapter.Fill(dataSet, "sample");
                    oracleDataAdapter.Dispose();
                    oracleConnection.Close();
                    record = "success";
                    return dataSet;
                }
            }
            catch (Exception ex)
            {
                DataSet dataSet = new DataSet();
                record = ex.Message.ToString();
                return dataSet;
            }
        }
    }
}

MySQL：

/*----------------------------------------------------------------
 * 
// author:HQ
 * 
// describe:MySQL
 * 
// date:2019-10-08
 * 
------------------------------------------------------------------*/
using System;
using System.Collections.Generic;
using System.Data;              //DataSet引用集
using MySql.Data.MySqlClient;   //MySQL引用
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace AdoNet
{
    public class MySQL : Database
    {
        private MySqlConnection mysql_con;

        /// <summary>
        /// MySQL open
        /// </summary>
        /// <param name="link">link statement</param>
        /// <returns>Success:success; Fail:reason</returns>
        public override string Open(string link)
        {
            try
            {
                mysql_con = new MySqlConnection(link);
                mysql_con.Open();
                return "success";
            }
            catch (Exception ex)
            {
                return ex.Message;
            }
        }

        /// <summary>
        /// MySQL close
        /// </summary>
        /// <returns>Success:success Fail:reason</returns>
        public override string Close()
        {
            try
            {
                if (mysql_con == null)
                {
                    return "No database connection";
                }
                if (mysql_con.State == ConnectionState.Open || mysql_con.State == ConnectionState.Connecting)
                {
                    mysql_con.Close();
                    mysql_con.Dispose();
                }
                else
                {
                    if (mysql_con.State == ConnectionState.Closed)
                    {
                        return "success";
                    }
                    if (mysql_con.State == ConnectionState.Broken)
                    {
                        return "ConnectionState:Broken";
                    }
                }
                return "success";
            }
            catch (Exception ex)
            {
                return ex.Message;
            }
        }

        /// <summary>
        /// MySQL insert,delete,update
        /// </summary>
        /// <param name="sql">insert,delete,update statement</param>
        /// <returns>Success:success + Number of affected rows; Fail:reason</returns>
        public override string Insdelupd(string sql)
        {
            try
            {
                int num = 0;
                if (mysql_con == null)
                {
                    return "Please open the database connection first";
                }
                if (mysql_con.State == ConnectionState.Open)
                {
                    MySqlCommand sqlCommand = new MySqlCommand(sql, mysql_con);
                    num = sqlCommand.ExecuteNonQuery();
                }
                else
                {
                    if (mysql_con.State == ConnectionState.Closed)
                    {
                        return "Database connection closed";
                    }
                    if (mysql_con.State == ConnectionState.Broken)
                    {
                        return "Database connection is destroyed";
                    }
                    if (mysql_con.State == ConnectionState.Connecting)
                    {
                        return "The database is in connection";
                    }
                }
                return "success" + num;
            }
            catch (Exception ex)
            {
                return ex.Message.ToString();
            }
        }

        /// <summary>
        /// MySQL insert,delete,update
        /// </summary>
        /// <param name="sql">insert,delete,update statement</param>
        /// <param name="link">link statement</param>
        /// <returns>Success:success + Number of affected rows; Fail:reason</returns>
        public override string Insdelupd(string sql, string link)
        {
            try
            {
                int num = 0;
                using (MySqlConnection con = new MySqlConnection(link))
                {
                    con.Open();
                    //操作数据库的工具SqlCommand
                    MySqlCommand cmd = new MySqlCommand(sql, con);  //(操作语句和链接工具)
                    num = cmd.ExecuteNonQuery();            //执行操作返回影响行数
                    con.Close();
                    return "success" + num;
                }
            }
            catch (Exception ex)
            {
                return ex.Message.ToString();
            }
        }

        /// <summary>
        /// MySQL select
        /// </summary>
        /// <param name="sql">select statement</param>
        /// <param name="record">Success:success; Fail:reason</param>
        /// <returns>select result</returns>
        public override DataSet Select(string sql, out string record)
        {
            try
            {
                //储存数据的工具初始化
                DataSet dataSet = new DataSet();
                if (mysql_con == null)
                {
                    record = "Please open the database connection first";
                    return dataSet;
                }
                if (mysql_con.State == ConnectionState.Open)
                {
                    MySqlDataAdapter sqlDataAdapter = new MySqlDataAdapter(sql, mysql_con);
                    sqlDataAdapter.Fill(dataSet, "sample");
                    sqlDataAdapter.Dispose();
                    record = "success";
                    return dataSet;
                }
                if (mysql_con.State == ConnectionState.Closed)
                {
                    record = "Database connection closed";
                    return dataSet;
                }
                if (mysql_con.State == ConnectionState.Broken)
                {
                    record = "Database connection is destroyed";
                    return dataSet;
                }
                if (mysql_con.State == ConnectionState.Connecting)
                {
                    record = "The database is in connection";
                    return dataSet;
                }
                record = "ERROR";
                return dataSet;
            }
            catch (Exception ex)
            {
                DataSet dataSet = new DataSet();
                record = ex.Message.ToString();
                return dataSet;
            }
        }

        /// <summary>
        /// MySQL select
        /// </summary>
        /// <param name="sql">select statement</param>
        /// <param name="link">link statement</param>
        /// <param name="record">Success:success; Fail:reason</param>
        /// <returns>select result</returns>
        public override DataSet Select(string sql, string link, out string record)
        {
            try
            {
                //储存数据的工具初始化
                DataSet ds = new DataSet();
                //相当于链接数据库的一个工具类（连接字符串）
                using (MySqlConnection con = new MySqlConnection(link))
                {
                    con.Open();                                         //打开
                    //用SqlConnection工具链接数据库，在通过sql查询语句查询结果现存入sql适配器
                    MySqlDataAdapter sda = new MySqlDataAdapter(sql, con);  //(查询语句和连接工具)
                    sda.Fill(ds, "sample");                             //将适配器数据存入DataSet工具中
                    con.Close();                                        //用完关闭SqlConnection工具
                    sda.Dispose();                                      //手动释放SqlDataAdapter
                    record = "success";
                    return ds;
                }
            }
            catch (Exception ex)
            {
                DataSet dataSet = new DataSet();
                record = ex.Message.ToString();
                return dataSet;
            }
        }
    }
}

Access：

/*----------------------------------------------------------------
 * 
// author:HQ
 * 
// describe:Access
 * 
// date:2019-10-08
 * 
------------------------------------------------------------------*/
using System;
using System.Collections.Generic;
using System.Data;          //DataSet引用
using System.Data.OleDb;    //Access引用
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace AdoNet
{
    public class Access
    {
        #region Access
        /// <summary>
        /// Access select
        /// </summary>
        /// <param name="sql">select statement</param>
        /// <param name="link">link statement</param>
        /// <param name="record">Success:success; Fail:reason</param>
        /// <returns>select result</returns>
        public DataSet Access_Mdb_Select(string sql, string link, out string record)
        {
            try
            {
                DataSet dataSet = new DataSet();
                using (OleDbConnection oleDbConnection = new OleDbConnection(link))
                {
                    oleDbConnection.Open();
                    OleDbDataAdapter oleDbDataAdapter = new OleDbDataAdapter(sql, oleDbConnection);
                    oleDbDataAdapter.Fill(dataSet, "sample");
                    oleDbDataAdapter.Dispose();
                    oleDbConnection.Close();
                    record = "success";
                    return dataSet;
                }
            }
            catch (Exception ex)
            {
                DataSet dataSet = new DataSet();
                record = ex.Message.ToString();
                return dataSet;
            }
        }

        /// <summary>
        /// Access insert,delete,update
        /// </summary>
        /// <param name="sql">insert,delete,update statement</param>
        /// <param name="link">link statement</param>
        /// <returns>Success:success + Number of affected rows; Fail:reason</returns>
        public string Access_Mdb_Insdelupd(string sql, string link)
        {
            try
            {
                using (OleDbConnection oleDbConnection = new OleDbConnection(link))
                {
                    DataSet dataSet = new DataSet();
                    oleDbConnection.Open();
                    OleDbCommand oleDbCommand = new OleDbCommand(sql, oleDbConnection);
                    int num = oleDbCommand.ExecuteNonQuery();
                    oleDbConnection.Close();
                    return "success" + num;
                }
            }
            catch (Exception ex)
            {
                return ex.Message.ToString();
            }
        }
        #endregion
    }
}

由于Access用的比较少就没做其他功能