c# 连接sql数据库的类应该怎么写？

Question

  c# 连接sql数据库的类应该怎么写？

Answer 1

string _connectionString = ConfigurationManager.ConnectionStrings["xxxx"].ConnectionString;
SqlConnection con = new SqlConnection(_connectionString);SqlCommand cmd = new SqlCommand();
cmd.Connection = con;
cmd.CommandText = ".....";
cmd.CommandType = CommandType.StoredProcedure;
using (con)
            {
                con.Open();
                SqlDataReader reader = cmd.ExecuteReader();
                while (reader.Read())
                {
                  .....
                   }
            }            ....
        }

Answer 2

类
class DBconnect
{
       public static SqlConnection sqlcon()
        {                      
            return new SqlConnection("server=.;Initial Catalog=chaoshi;Integrated Security=True");        }}
调用时。。SqlConnection con=DBconnect.sqlcon();

Answer 3

using System;
using System.Data;
using AuditOnline.Common.ExceptionHandler;namespace AuditOnline.Common.DataAccess
{
    /// <summary>
    /// 提供对数据表进行数据访问
    /// </summary>
    public abstract class DataAccessor
    {
        /// <summary>
        /// 更新与DataRow绑定的对象
        /// </summary>
        /// <param name="binder"></param>
        public void Update(IDataBinder binder)
        {
            binder.BindToRow();
            UpdateDataSet(binder);
        }        /// <summary>
        /// 更新一条记录
        /// </summary>
        /// <param name="binder"></param>
        private void UpdateDataSet(IDataBinder binder)
        {
            string sql = string.Format("select * from {0}", TableName);
            if (binder.Row.Table.DataSet == null)
            {
                DataSet ds = new DataSet();
                ds.Tables.Add(binder.Row.Table);
            }
            try
            {
                WebServiceCommon.Instance.SystemServiceCommon.UpdateDataSet(sql, binder.Row.Table.DataSet);
            }
            catch (Exception ex)
            {
                ExceptionRecords.AddExceptionRecords(this.GetType(), ex);
                throw ex;
            }            try
            {
                binder.Row.AcceptChanges();
            }
            catch (Exception ex)
            {
                ExceptionRecords.AddExceptionRecords(this.GetType(), ex);
            }
        }        /// <summary>
        /// 删除一个与DataRow绑定的对象
        /// </summary>
        /// <param name="findedmodel"></param>
        public virtual void Delete(IDataBinder findedmodel)
        {
            findedmodel.Row.Delete();
            UpdateDataSet(findedmodel);
        }        /// <summary>
        ///  查询当前表所有数据集
        /// </summary>
        /// <returns></returns>
        public DataTable FindAll()
        {
            string sql = string.Format("select * from {0}  ", TableName);
            DataSet ds = null;
            try
            {
                ds = WebServiceCommon.Instance.SystemServiceCommon.SysQuery(sql);
            }
            catch (Exception ex)
            {
                ExceptionRecords.AddExceptionRecords(this.GetType(), ex);
                throw ex;
            }
            return ds.Tables[0];
        }        /// <summary>
        /// 通过条件查询当前关联表名的数据集
        /// </summary>
        /// <param name="clause"></param>
        /// <returns></returns>
        public DataTable FindByWhereClause(string clause)
        {
            string sql = string.Format("select * from {0} where {1} ", TableName, clause);
            DataSet ds = null;
            try
            {
                ds = WebServiceCommon.Instance.SystemServiceCommon.SysQuery(sql);
            }
            catch (Exception ex)
            {
                ExceptionRecords.AddExceptionRecords(this.GetType(), ex);
                throw ex;
            }
            return ds.Tables[0];
        }        /// <summary>
        /// 通过SQL语句查询数据集
        /// </summary>
        /// <param name="sqlString"></param>
        /// <returns></returns>
        public DataTable FindBySQLString(String sqlString)
        {
            string sql = string.Format(sqlString);
            DataSet ds = null;
            try
            {
                ds = WebServiceCommon.Instance.SystemServiceCommon.SysQuery(sql);
            }
            catch (Exception ex)
            {
                ExceptionRecords.AddExceptionRecords(this.GetType(), ex);
                throw ex;
            }
            return ds.Tables[0];
        }        /// <summary>
        /// 通过SQL语句查询数据集（重复）
        /// </summary>
        /// <param name="sqlString"></param>
        /// <returns></returns>
        public DataSet FillDataToDataSet(String sqlString)
        {
            string sql = string.Format(sqlString);
            DataSet ds = null;
            try
            {
                ds = WebServiceCommon.Instance.SystemServiceCommon.SysQuery(sql);
            }
            catch (Exception ex)
            {
                ExceptionRecords.AddExceptionRecords(this.GetType(), ex);
                throw ex;
            }
            return ds;
        }        /// <summary>
        /// 当前关联的表的名称
        /// </summary>
        public abstract string TableName
        {
            get;
        }
        /// <summary>
        ///  执行SQL语句
        /// </summary>
        /// <param name="sql"></param>
        /// <returns>该SQL语句执行后受影响的行数</returns>
        public int ExcuteNoQuery(string sql)
        {
            try
            {
                return WebServiceCommon.Instance.SystemServiceCommon.SysExecuteNoQuery(sql);
            }
            catch (Exception ex)
            {
                ExceptionRecords.AddExceptionRecords(this.GetType(), ex);
                throw ex;
            }
        }
    }
}