ADO.NET操作SQL Server：数据库操作类(未封装)

1.添加数据

        /// <summary>
        /// 添加数据
        /// </summary>
        /// <param name="newEntity"></param>
        /// <returns></returns>
        public static int Insert(Student newEntity)
        {
            string sql = @"insert into [Student] ([StudentId],[StudentNo],[IdCard],[RealName]) values (@StudentId,@StudentNo,@IdCard,@RealName)";
            using (SqlConnection conn = new SqlConnection(datalink.ConnectionString))
            {
                using (SqlCommand cmd = new SqlCommand(sql, conn))
                {
                    #region MyRegion
                    cmd.Parameters.Add("@StudentId", SqlDbType.UniqueIdentifier).Value = newEntity.StudentId;
                    cmd.Parameters.Add("@StudentNo", SqlDbType.Int).Value = newEntity.StudentNo;
                    cmd.Parameters.Add("@IdCard", SqlDbType.NVarChar).Value = newEntity.IdCard ?? (object)DBNull.Value;
                    cmd.Parameters.Add("@RealName", SqlDbType.NVarChar).Value = newEntity.RealName ?? (object)DBNull.Value;
                    #endregion

                    conn.Open();
                    return cmd.ExecuteNonQuery();
                }
            }
        }

2.修改数据

        /// <summary>
        /// 修改数据
        /// </summary>
        /// <param name="updateEntity"></param>
        /// <returns></returns>
        public static int Update(Student updateEntity)
        {
            string sql = @"update [Student] set [StudentNo]=@StudentNo,[IdCard]=@IdCard,[RealName]=@RealName where [StudentId]=@StudentId";
            using (SqlConnection conn = new SqlConnection(datalink.ConnectionString))
            {
                using (SqlCommand cmd = new SqlCommand(sql, conn))
                {
                    #region MyRegion
                    cmd.Parameters.Add("@StudentId", SqlDbType.UniqueIdentifier).Value = updateEntity.StudentId;
                    cmd.Parameters.Add("@StudentNo", SqlDbType.Int).Value = updateEntity.StudentNo;
                    cmd.Parameters.Add("@IdCard", SqlDbType.NVarChar).Value = updateEntity.IdCard ?? (object)DBNull.Value;
                    cmd.Parameters.Add("@RealName", SqlDbType.NVarChar).Value = updateEntity.RealName ?? (object)DBNull.Value;
                    #endregion

                    conn.Open();
                    return cmd.ExecuteNonQuery();
                }
            }
        }

3.删除数据

        /// <summary>
        /// 删除数据
        /// </summary>
        /// <param name="studentId"></param>
        /// <returns></returns>
        public static int Delete(Guid studentId)
        {
            string sql = @"delete from [Student] where [StudentId]=@StudentId";
            using (SqlConnection conn = new SqlConnection(datalink.ConnectionString))
            {
                using (SqlCommand cmd = new SqlCommand(sql, conn))
                {
                    cmd.Parameters.Add("@StudentId", SqlDbType.UniqueIdentifier).Value = studentId;
                    conn.Open();
                    return cmd.ExecuteNonQuery();
                }
            }
        }

4.读取数据

        /// <summary>
        /// 读取数据
        /// </summary>
        /// <param name="reader"></param>
        /// <returns></returns>
        private static Student Reader(SqlDataReader reader)
        {
            Student newEntity = new Student();
            if (reader != null && !reader.IsClosed)
            {
                if (reader["StudentId"] != DBNull.Value) newEntity.StudentId = (Guid)reader["StudentId"];
                if (reader["StudentNo"] != DBNull.Value) newEntity.StudentNo = (int)reader["StudentNo"];
                if (reader["IdCard"] != DBNull.Value) newEntity.IdCard = (string)reader["IdCard"];
                if (reader["RealName"] != DBNull.Value) newEntity.RealName = (string)reader["RealName"];
            }
            return newEntity;
        }

5.查询1行数据

        /// <summary>
        /// 查询1行数据
        /// </summary>
        /// <param name="studentId"></param>
        /// <returns></returns>
        public static Student GetEntity(Guid studentId)
        {
            Student entity = null;
            string sql = @"select * from [Student] where [StudentId]=@StudentId";
            using (SqlConnection conn = new SqlConnection(datalink.ConnectionString))
            {
                using (SqlCommand cmd = new SqlCommand(sql, conn))
                {
                    cmd.Parameters.Add("@StudentId", SqlDbType.UniqueIdentifier).Value = studentId;
                    conn.Open();
                    using (SqlDataReader sr = cmd.ExecuteReader())
                    {
                        while (sr.Read())
                        {
                            entity = Reader(sr);
                        }
                    }
                }
            }
            return entity;
        }

6.查询n行数据

        /// <summary>
        /// 查询n行数据
        /// </summary>
        /// <returns></returns>
        public static List<Student> SearchAllList()
        {
            List<Student> list = new List<Student>();
            string sql = @"select * from [Student]";
            using (SqlConnection conn = new SqlConnection(datalink.ConnectionString))
            {
                using (SqlCommand cmd = new SqlCommand(sql, conn))
                {
                    conn.Open();
                    using (SqlDataReader sr = cmd.ExecuteReader())
                    {
                        while (sr.Read())
                        {
                            Student info = Reader(sr);
                            list.Add(info);
                        }
                    }
                }
            }
            return list;
        }

7.添加数据列表

        /// <summary>
        /// 添加数据列表
        /// </summary>
        /// <param name="newEntityList"></param>
        /// <param name="message"></param>
        /// <returns></returns>
        public static bool Insert(List<Student> newEntityList, out string message)
        {
            message = string.Empty;
            int rows = 0;
            string sql = @"insert into [Student] ([StudentId],[StudentNo],[IdCard],[RealName]) values (@StudentId,@StudentNo,@IdCard,@RealName)";
            using (SqlConnection conn = new SqlConnection(datalink.ConnectionString))
            {
                conn.Open();

                SqlCommand cmd = conn.CreateCommand();
                SqlTransaction tran = conn.BeginTransaction();
                cmd.CommandText = sql;
                cmd.Connection = conn;
                cmd.Transaction = tran;

                try
                {
                    //打开数据库连接后，循环执行insert语句。在循环过程中，如果没有出现异常，则提交事务；如果出现异常，则回滚事务。
                    foreach (var newEntity in newEntityList)
                    {
                        cmd.Parameters.Clear();//注意

                        #region MyRegion
                        cmd.Parameters.Add("@StudentId", SqlDbType.UniqueIdentifier).Value = newEntity.StudentId;
                        cmd.Parameters.Add("@StudentNo", SqlDbType.Int).Value = newEntity.StudentNo;
                        cmd.Parameters.Add("@IdCard", SqlDbType.NVarChar).Value = newEntity.IdCard ?? (object)DBNull.Value;
                        cmd.Parameters.Add("@RealName", SqlDbType.NVarChar).Value = newEntity.RealName ?? (object)DBNull.Value;
                        #endregion

                        rows += cmd.ExecuteNonQuery();
                    }
                    message = rows.ToString();
                    tran.Commit();//提交事务
                    return true;
                }
                catch (Exception e)
                {
                    message = e.Message;
                    tran.Rollback();//回滚事务
                    return false;
                }
            }
        }

8.修改数据列表

        /// <summary>
        /// 修改数据列表
        /// </summary>
        /// <param name="updateEntityList"></param>
        /// <param name="message"></param>
        /// <returns></returns>
        public static bool Update(List<Student> updateEntityList, out string message)
        {
            message = string.Empty;
            int rows = 0;
            string sql = @"update [Student] set [StudentNo]=@StudentNo,[IdCard]=@IdCard,[RealName]=@RealName where [StudentId]=@StudentId";
            using (SqlConnection conn = new SqlConnection(datalink.ConnectionString))
            {
                conn.Open();

                SqlCommand cmd = conn.CreateCommand();
                SqlTransaction tran = conn.BeginTransaction();
                cmd.CommandText = sql;
                cmd.Connection = conn;
                cmd.Transaction = tran;

                try
                {
                    //打开数据库连接后，循环执行insert语句。在循环过程中，如果没有出现异常，则提交事务；如果出现异常，则回滚事务。
                    foreach (var newEntity in updateEntityList)
                    {
                        cmd.Parameters.Clear();//注意
                        #region MyRegion
                        cmd.Parameters.Add("@StudentId", SqlDbType.UniqueIdentifier).Value = newEntity.StudentId;
                        cmd.Parameters.Add("@StudentNo", SqlDbType.Int).Value = newEntity.StudentNo;
                        cmd.Parameters.Add("@IdCard", SqlDbType.NVarChar).Value = newEntity.IdCard ?? (object)DBNull.Value;
                        cmd.Parameters.Add("@RealName", SqlDbType.NVarChar).Value = newEntity.RealName ?? (object)DBNull.Value;
                        #endregion
                        rows += cmd.ExecuteNonQuery();
                    }
                    message = rows.ToString();
                    tran.Commit();//提交事务
                    return true;
                }
                catch (Exception e)
                {
                    message = e.Message;
                    tran.Rollback();//回滚事务
                    return false;
                }
            }
        }

9.删除数据列表

        /// <summary>
        /// 删除数据列表
        /// </summary>
        /// <param name="studentIdList"></param>
        /// <param name="message"></param>
        /// <returns></returns>
        public static bool Delete(List<Student> studentIdList, out string message)
        {
            message = string.Empty;
            int rows = 0;
            string sql = @"delete from [Student] where [StudentId]=@StudentId";
            using (SqlConnection conn = new SqlConnection(datalink.ConnectionString))
            {
                conn.Open();

                SqlCommand cmd = conn.CreateCommand();
                SqlTransaction tran = conn.BeginTransaction();

                cmd.CommandText = sql;
                cmd.Connection = conn;
                cmd.Transaction = tran;

                try
                {
                    //打开数据库连接后，循环执行insert语句。在循环过程中，如果没有出现异常，则提交事务；如果出现异常，则回滚事务。
                    foreach (var studentId in studentIdList)
                    {
                        cmd.Parameters.Clear();//注意
                        cmd.Parameters.Add("@StudentId", SqlDbType.UniqueIdentifier).Value = studentId;
                        rows += cmd.ExecuteNonQuery();
                    }
                    message = rows.ToString();
                    tran.Commit();//提交事务
                    return true;
                }
                catch (Exception e)
                {
                    message = e.Message;
                    tran.Rollback();//回滚事务
                    return false;
                }
            }
        }