Introduction to ADO, VB Database Tools and Data .ppt

1、Introduction to ADO.Net, VB.Net Database Tools and Data Binding,ISYS 512,Client/Server Structure,a. Presentation user interface Menus, forms, reports, etc b. Processing logic Business rules c. Database,Client,Database Server,SQL queries,Results,Database Processing,Querying database Updating database

2、: Insertion, deletion, modification,Steps to Retrieve Data,Establishes a connection to the database. Executes commands against the database. Store data results.,A Simplified View of ADO.Net Objects,Ado.Net,Data Provider,Connection,Adapter,Command,Reader,Dataset,Data Consumer,WinForm,WebForm,ADO.NET

3、Objects,Connection Object: Represent a connection to the database. Command Object: The command object allows us to execute a SQL statement or a stored procedure. DataReader: It is a read-only and forward-only pointer into a table to retrieve records. DataSet Object: A DataSet object can hold several

4、 tables and relationships between tables. DataAdapter: This the object used to pass data between the database and the dataset.,Data Providers,ODBC Provider Open Database Connectivity A driver manager Used for relational databases OLE DB Provider OLE DB interfaces provide applications with uniform ac

5、cess to data stored in diverse information sources, or data stores. Access SQL Server Provider Oracle Provider,Using ODBC,Windows XP: Control Panel /Administrative Tools/DataSource(ODBC) Three types of data source names User DSN: usable only by you and only on the machine currently using. System DSN

6、: Any one using the machine can use. File DSN: Can be copied and used by other computers with the same driver installed. Demo: Excel: Data/Import Access: File/Get External Data/Import, then select ODBC data source,VB.NET Database Tools,Database connection: Tools/Connect to database Data Source Serve

7、r Explorer Data connections: Right click data connection Add Connection Tables, Views Create new SQL Server Database Toolbox:Data tab Data/Add New Data Source,Creating SQL Server Database,From Server Explorer, right click data connection and choose: Create new SQL Server Database Server name: LocalS

8、erverNameSQLExpress Add new table: Right click Tables and choose Add New Table Add rows: Right click the table name and choose Show table data. Note: After creating the database, you may create an ODBC DSN to connect to it.,How to create ADO.Net objects?,Automatically generated when creating data bo

9、und form. Form wizard Using Data Adapter Wizard Using code: Example: dim strConn as string =“Provider=Microsoft.Jet.OLEDB.4.0;Data Source = c:sales2k.mdb“ dim objConn as new OledbConnection(strConn) objConn.open(),Data Binding,Connect a control or property to one or more data elements. Simple bindin

10、g: Use simple binding to display a field value in controls that show Data Bindings in the property window, such as text box or label. Complex binding: Use complex binding to bind more than one field to controls such as DataGrid and list box. Use the controls Data Source and Data Member to bind the d

11、ata.,Creating Data Bound Form,Creating a form with ADO.Net objects and data-bound controls to display and update information in a dataset. Demo: Add data source: Data/Add New Data Source Data/Show Data Source Click the dropdown list next to the tables name: Datagrid view Details Drag the table to fo

12、rm.,Items Added to the Form,Connection Table Adapter: click smart tag Add query Preview data Dataset: Edit in dataset designer Binding Source Add query: Add a new tool strip. Preview data Binding navigator Code view: Form load event,Generated Code,Private Sub CUSTOMERBindingNavigatorSaveItem_Click(B

13、yVal sender As System.Object, ByVal e As System.EventArgs) Handles CUSTOMERBindingNavigatorSaveItem.ClickMe.Validate()Me.CUSTOMERBindingSource.EndEdit()Me.CUSTOMERTableAdapter.Update(Me.SalesDBDataSet.CUSTOMER) End SubPrivate Sub Form3_Load(ByVal sender As System.Object, ByVal e As System.EventArgs)

14、 Handles MyBase.LoadTODO: This line of code loads data into the SalesDBDataSet.CUSTOMER table. You can move, or remove it, as needed.Me.CUSTOMERTableAdapter.Fill(Me.SalesDBDataSet.CUSTOMER) End Sub,Other Data Form Demos,DataGrid View Add /Modify/Delete records. Read only form: Delete AddNew, Delete,

15、 Save buttons from navigator bar.,Hierarchical Forms,Parent table/Child table Add parent table and child table to Data Source Drag the parent table and the child table to the form. Parent table uses detail view and child table uses dataGrid view Click Dataset objects smart tag to choose Edit in Data

16、set Designer With the designer, right click the parent table and choose Add/Relation Change dataGrids DataSource property to the relation.,Detail Form with Bound ListBox,Example: Customer table form with CID listbox and displays selected customer information in textboxes. Choose detail view for the

17、customer table. Click the dropdown list next to the CID field and click ListBox Drag the Customer table to the form. Bind the CID field to the BindingSource: Activate the Property window and click the listbox Set the DataSOurce property to BindingSource Set the Display Member property to CID,Creatin

18、g A Database Application Without Programming,Creating a database application to display information and update database. A main form with buttons to open data forms: DisplayInfo Enter New Modify Exit,Data Adapter Wizard,Configure Data Adapter and generating a dataset: From the Data tab of the ToolBo

19、x, Drag OledbDataAdapter to the form. Use the Data Adapter Wizard to configure the Adapter. Right Click the Adapter to preview data and create dataset. Bind the dataset to controls. In the Form Load event, use Adapters Fill method to load the dataset: OleDbDataAdapter1.Fill(DataSet11),Creating Bound

20、 DataGridView,DataGridView control: Data Source property: DataSet Data Member property A table in the dataset In the Form Load event, use Adapters Fill method to load the dataset: OleDbDataAdapter1.Fill(DataSet11) Note: A BindingSource object is created after choosing data source.,BindingSource Obje

21、ct,It is an object that keeps track of position (the current row) of a data source. Useful properties: DataSource DataMember Position property: is the index of the current row. The index is a 0-based index, the first record has a position of 0. Methods: MoveFirst, MoveLast, MoveNext, MovePrevious Ad

22、dNew AllowEdit EndEdit,Adding AddNew and Save Button,Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.ClickCUSTOMERBindingSource.AddNew()End SubPrivate Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.C

23、lickCUSTOMERBindingSource.EndEdit()CUSTOMERTableAdapter.Update(SalesDBDataSet1.CUSTOMER)End Sub,Adding AddNew and Save Button,AddNew button: Use BindingSource AddNew Method:,Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.ClickCUSTOMERBindingSour

24、ce.AddNew()End Sub,Save button: Use BindingSource EndEdit method and Adapters Update method:,Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.ClickCUSTOMERBindingSource.EndEdit() CUSTOMERTableAdapter.Update(SalesDBDataSet1.CUSTOMER)End Sub,Binding

25、Sources Position Property,If controls are bound to a BindingSource object, to move the current record we change the Position property of the BindingSource object: To move to the next record:Me.EmpBindingSource.Position += 1 Or Me.EmpBindingSource.MoveNext To move to the previous record:Me.EmpBinding

26、Source.Position -= 1 Or Me.EmpBindingSource.MovePrevious,Binding Text Box,Select Data Bindings property: Text: choose field Add navigation buttons: MoveNext: CUSTOMERBindingSource.Position += 1 MovePrevious: CUSTOMERBindingSource.Position -= 1,Other Objects Related to Data Binding,BindingContext: It

27、 is an object that manages a collection of data sources used for binding. CurrencyManager: It is an object that keeps track of position (the current row) of a data source. Two useful properties: Position property: is the index of the current row. The index is a 0-based index, the first record has a

28、position of 0. Count property: The number of rows in the data source.,MoveNext and MoveLast Example,MoveNext:Me.BindingContext(DataSet21, “customer“).Position += 1MoveLast: Me.BindingContext(DataSet21, “customer“).Position = Me.BindingContext(DataSet21, “customer“).Count -1How to MovePrevious and Mo

29、veFirst? Note: The Position property takes care of the end of file automatically. Note: Me.BindingContext(DataSet21, “customer“) returns a CurrencyManager object.,BindingNavigator Object,This object automatically adds navigation buttons to the form. Property: BindingSource property Specify a Binding

30、Source object (Must first define a BindingSource object),Binding ListBox,Example: Bind Customer Tables CID field to a listbox. Create a Adapter for Customer table , and generate the dataset. Add ListBox and set binding properties: Data Source: Customer table Display Member: Field to display in the l

31、istbox. Value Member: the actual values for items in the list box.,Display Selected Record,Bound textbox (same data source as the listbox): If the Listbox and the textbox are bound to the same BindingSource object, the textbox will automatically displays the record of the selected listbox item. Unbo

32、und textbox To display the ValueMember Textbox1.text = ListBox1.SelectedValue To display other fields: Textbox1.text = ListBox1.SelectedItem(“Cname”) Can we use TextBox1.text=ListBox1.SelectedItem?No!,ListBox SelectedItem Property,How to display the selected record in unbound textbox? After binding

33、to a data source, this property return a DataRowView object. What is DataRowView? Object Browser: System.Data DataRowView: Item property is the default property To retrieve a column from a DataRowView object (use 0-based index to identity a column): ListBox1.SelectedItem.Item(1) Or: ListBox1.SelectedItem(1) Or: ListBox1.SelectedItem(“Cname”),Using Object Browser,View/Object Browser DataSet object model: System.Data DataSet Relations Tables Rows Columns Use Object Browser to study objects properties, methods.,