今天小編給大家分享一下如何完成一個(gè)小型工程報(bào)價(jià)數(shù)據(jù)庫(kù)系統(tǒng)的相關(guān)知識(shí)點(diǎn)，內(nèi)容詳細(xì)，邏輯清晰，相信大部分人都還太了解這方面的知識(shí)，所以分享這篇文章給大家參考一下，希望大家閱讀完這篇文章后有所收獲，下面我們一起來(lái)了解一下吧。

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功能很簡(jiǎn)單，完成基本的增刪改查

• 搭建項(xiàng)目三層結(jié)構(gòu)

• 界面的設(shè)計(jì)以及美化

• 分層代碼的設(shè)計(jì)與實(shí)現(xiàn)

1.模型層：由于表設(shè)計(jì)時(shí)存在主外鍵關(guān)系，故把表映射成對(duì)象時(shí)添加一個(gè)外鍵對(duì)象來(lái)保存外鍵那張表的相關(guān)數(shù)據(jù)。

// 外鍵實(shí)體              private Product _product;              private Project _project;               public Project _Project              {                  get { return _project; }                  set { _project = value; }              }               public Product _Product              {                  get { return _product; }                  set { _product = value; }              }

2.數(shù)據(jù)訪問(wèn)層：把數(shù)據(jù)封裝成Model對(duì)象的各層之間傳遞。

我個(gè)人不喜歡三層之間傳遞DataSet數(shù)據(jù)集，我的理解是盡量不在BLL層出現(xiàn)DataSet，所以我在DAL層把所有獲取的數(shù)據(jù)封裝成IEnumerable集合，然后返回。

protected IEnumerable ToModelsByFK(SqlDataReader reader)           {               var list = new List();               while (reader.Read())               {                   list.Add(ToModelByFK(reader));               }               return list;           }

public ProjectItem ToModelByFK(SqlDataReader reader)           {               ProjectItem projectItem = new ProjectItem();               projectItem._Product = new Product();               projectItem._Project = new Project();               projectItem.ID = (int)ToModelValue(reader, "ID");               projectItem._Product.ID = (int)ToModelValue(reader, "ProductID");               projectItem._Project.ID = (int)ToModelValue(reader,"projectID");               projectItem._Product.Manufacturer = ToModelValue(reader, "Manufacturer").ToString();               projectItem._Product.Parameters = ToModelValue(reader, "Parameters").ToString();               projectItem._Product.Price = decimal.Parse( ToModelValue(reader, "Price").ToString());               projectItem._Product.ProductName = ToModelValue(reader, "ProductName").ToString();               projectItem._Product.Specification = ToModelValue(reader, "Specification").ToString();               projectItem._Product.Unit = ToModelValue(reader, "Unit").ToString();               projectItem.Count = (int)ToModelValue(reader, "Count");               projectItem.TotalMoney = (decimal)ToModelValue(reader, "TotalMoney");               projectItem.UnitPrice = (decimal)ToModelValue(reader, "UnitPrice");                return projectItem;           }

protected object ToModelValue(SqlDataReader reader,string columnName)          {              if(reader.IsDBNull(reader.GetOrdinal(columnName)))              {                  return null;              }              else             {                  return reader[columnName];              }          }

使用GetProjectByCondition方法返回一個(gè)封裝成對(duì)象的 IEnumerable集合

public IEnumerable GetProjectByCondition(string projectName, string customerName, string contract, string tel)          {              StringBuilder sqlWhere = new StringBuilder("select * from Project where 1=1");              List listParameters = new List();              if (!string.IsNullOrWhiteSpace(projectName))              {                  sqlWhere.AppendLine(" and projectName like @projectName");                  listParameters.Add(new SqlParameter("projectName", "%" + projectName + "%"));              }              if (!string.IsNullOrWhiteSpace(contract))              {                  sqlWhere.AppendLine(" and Contact like @Contact");                  listParameters.Add(new SqlParameter("Contact", "%" + contract + "%"));              }              if (!string.IsNullOrWhiteSpace(customerName))              {                  sqlWhere.AppendLine(" and customer like @customer");                  listParameters.Add(new SqlParameter("customer", "%" + customerName + "%"));              }              if (!string.IsNullOrWhiteSpace(tel))              {                  sqlWhere.AppendLine(" and tel like @tel");                  listParameters.Add(new SqlParameter("tel", "%" + tel + "%"));              }              using (SqlDataReader reader = SqlHelper.ExecuteDataReader(sqlWhere.ToString(), listParameters.ToArray()))              {                  return ToModels(reader);              }           }

UpdatePassChecked方法接受一個(gè)對(duì)象，通過(guò)對(duì)象的屬性來(lái)獲取數(shù)據(jù)

public int UpdatePassChecked(ProjectItem projectItem)           {               string sql =                   "UPDATE Project " +                   "SET " +               " ProjectName = @ProjectName"                  + ", Customer = @Customer"                  + ", Contact = @Contact"                  + ", Tel = @Tel"                  + ", DeliveryPlace = @DeliveryPlace"                  + ", DeliveryTime = @DeliveryTime"                  + ", TransportCosts = @TransportCosts"                  + ", PaymentTerm = @PaymentTerm"                  + ", Bak = @Bak"               + " WHERE ID = @ID";                 SqlParameter[] para = new SqlParameter[]              {                  new SqlParameter("@ID", projectItem._Project.ID)                      ,new SqlParameter("@ProjectName", ToDBValue(projectItem._Project.ProjectName))                      ,new SqlParameter("@Customer", ToDBValue(projectItem._Project.Customer))                      ,new SqlParameter("@Contact", ToDBValue(projectItem._Project.Contact))                      ,new SqlParameter("@Tel", ToDBValue(projectItem._Project.Tel))                      ,new SqlParameter("@DeliveryPlace", ToDBValue(projectItem._Project.DeliveryPlace))                      ,new SqlParameter("@DeliveryTime", ToDBValue(projectItem._Project.DeliveryTime))                      ,new SqlParameter("@TransportCosts", ToDBValue(projectItem._Project.TransportCosts))                      ,new SqlParameter("@PaymentTerm", ToDBValue(projectItem._Project.PaymentTerm))                      ,new SqlParameter("@Bak", ToDBValue(projectItem._Project.Bak))              };                return SqlHelper.ExecuteNonQuery(sql, para);            }

Add方法傳入一個(gè)已經(jīng)把數(shù)據(jù)封裝好的對(duì)象，然后返回一個(gè)新的對(duì)象（包含新創(chuàng)建生成的ID）

public Product Add(Product product)          {                  string sql ="INSERT INTO Product (ProductName, Specification, Manufacturer, Parameters, Price, Unit)  output inserted.ID VALUES (@ProductName, @Specification, @Manufacturer, @Parameters, @Price, @Unit)";                  SqlParameter[] para = new SqlParameter[]                      {                          new SqlParameter("@ProductName", ToDBValue(product.ProductName)),                          new SqlParameter("@Specification", ToDBValue(product.Specification)),                          new SqlParameter("@Manufacturer", ToDBValue(product.Manufacturer)),                          new SqlParameter("@Parameters", ToDBValue(product.Parameters)),                          new SqlParameter("@Price", ToDBValue(product.Price)),                          new SqlParameter("@Unit", ToDBValue(product.Unit)),                      };                                        int newId = (int)SqlHelper.ExecuteScalar(sql, para);                  return GetByID(newId);          }

3.業(yè)務(wù)邏輯層：業(yè)務(wù)邏輯層是項(xiàng)目的核心，業(yè)務(wù)邏輯上的代碼通常在這兒實(shí)現(xiàn)（一言難盡）。

簡(jiǎn)單數(shù)據(jù)驗(yàn)證：

public bool UpdateThroughChecked(ProjectItem projectItem)          {              if (string.IsNullOrEmpty(projectItem._Project.ProjectName))              {                  throw new Exception("項(xiàng)目名稱不能為空");              }              //顧客姓名可以為空，但聯(lián)系人不能為空，所以數(shù)據(jù)庫(kù)里就應(yīng)該設(shè)計(jì)好              if (string.IsNullOrEmpty(projectItem._Project.Contact))              {                  throw new Exception("聯(lián)系人姓名不能為空");              }              if (string.IsNullOrEmpty(projectItem._Project.Tel))              {                  throw new Exception("聯(lián)系電話不能為空");              }              if (string.IsNullOrEmpty(projectItem._Project.DeliveryPlace))              {                  throw new Exception("交貨地點(diǎn)不能為空");              }              if (string.IsNullOrEmpty(projectItem._Project.DeliveryTime))              {                  throw new Exception("交貨時(shí)間不能為空");              }              if (projectItem._Project.TransportCosts<00)              {                  throw new Exception("運(yùn)輸費(fèi)用不能為負(fù)數(shù)");              }              return new DAL.ProjectItemService().UpdatePassChecked(projectItem) > 0;           }

計(jì)算總金額：

public decimal GetProductTotalMoney(int projectID)          {              var list = new DAL.ProjectItemService().GetProductTotalMoney(projectID);              decimal  totalMoney = 0.00M;              foreach (var model in list)              {                  totalMoney+=model.TotalMoney.Value;              }              return totalMoney;          }

根據(jù)查詢條件獲取數(shù)據(jù)集合：

/// 
          /// 根據(jù)查詢條件獲取數(shù)據(jù)集合          /// 
          ///           ///           public IEnumerable GetProductsByCondition(string condition)          {             return new DAL.ProductService().GetProductsByCondition(condition);                   }

根據(jù)ProjectItemID獲取一條記錄（封裝成對(duì)象）

public Model.ProjectItem GetOneProjectItemByID(int ProjectItemID)          {              return new DAL.ProjectItemService().GetOneProjectItemByID(ProjectItemID);          }

增加一條記錄：

/// 
          /// 新增一條記錄 根據(jù)條件          /// 
          ///           ///           public Model.Project AddPassCheckd(Model.Project modelProject)          {               if (string.IsNullOrEmpty(modelProject.ProjectName))              {                  throw new Exception("項(xiàng)目名稱不能為空");              }              if (string.IsNullOrEmpty(modelProject.Customer))              {                  throw new Exception("顧客名稱不能為空");              }              if (string.IsNullOrEmpty(modelProject.Tel))              {                  throw new Exception("聯(lián)系電話不能為空");              }              if (modelProject.TransportCosts <= 0)              {                  throw new Exception("運(yùn)輸費(fèi)用不能為負(fù)數(shù):(");              }              return new DAL.ProjectService().Add(modelProject);                       }

刪除一個(gè)項(xiàng)目：

/// 
          /// 刪除一個(gè)項(xiàng)目          /// 
          ///           ///           public bool DeleteProject(int projectID)          {               bool isSucceed=  new BLL.ProjectItemManager().DeleteProjectItemsByProjectID(projectID);               isSucceed = new DAL.ProjectService().DeleteByID(projectID) > 0 && isSucceed;               return isSucceed;          }

4.表現(xiàn)層（UI）

簡(jiǎn)單的窗體里嵌套窗體：

public void LoadProjectListForm()          {              projectListForm = null;              if (projectListForm==null)              {                  projectListForm = new ProjectListForm();              }              //去掉邊框              projectListForm.FormBorderStyle = FormBorderStyle.None;              projectListForm.TopLevel = false;//窗體是否是頂級(jí)窗體              projectListForm.Dock = DockStyle.Fill;//填充              projectListForm.Show();//不寫看不到              panelContainer.Controls.Clear();//清空              panelContainer.Controls.Add(projectListForm);          }

綁定數(shù)據(jù)：

void LoadData()          {              var list = new BLL.ProjectItemManager().GetAllProducts(projectID);              //dataGridViewProjectItems.DataSource = list;//當(dāng)控件被綁定時(shí)無(wú)法向其添加Row              dataGridViewProjectItems.Rows.Clear();              foreach (var model in list)              {                  int i = dataGridViewProjectItems.Rows.Add();                  dataGridViewProjectItems.Rows[i].Cells["idColumn"].Value = model.ID;                  dataGridViewProjectItems.Rows[i].Cells["specificationColumn"].Value = model._Product.Specification;                  dataGridViewProjectItems.Rows[i].Cells["productNameColumn"].Value = model._Product.ProductName;                  dataGridViewProjectItems.Rows[i].Cells["manufacturerColumn"].Value = model._Product.Manufacturer;                  dataGridViewProjectItems.Rows[i].Cells["parametersColumn"].Value = model._Product.Parameters;                  dataGridViewProjectItems.Rows[i].Cells["productIDColumn"].Value = model._Product.ID;                  dataGridViewProjectItems.Rows[i].Cells["totalMoneyColumn"].Value = model.TotalMoney;                  dataGridViewProjectItems.Rows[i].Cells["countColumn"].Value = model.Count;                  dataGridViewProjectItems.Rows[i].Cells["unitPriceColumn"].Value = model.UnitPrice;                  dataGridViewProjectItems.Rows[i].Cells["projectIDColumn"].Value = model._Project.ID;              }

以上就是“如何完成一個(gè)小型工程報(bào)價(jià)數(shù)據(jù)庫(kù)系統(tǒng)”這篇文章的所有內(nèi)容，感謝各位的閱讀！相信大家閱讀完這篇文章都有很大的收獲，小編每天都會(huì)為大家更新不同的知識(shí)，如果還想學(xué)習(xí)更多的知識(shí)，請(qǐng)關(guān)注創(chuàng)新互聯(lián)行業(yè)資訊頻道。