Transcript Visual Basic Database Access

Introduction to ADO.Net, VB.Net
Database Tools and Data Binding
ISYS 350
Client/Server Structure
a. Presentation – user interface
• Menus, forms, reports, etc
b. Processing logic
• Business rules
c. Database
SQL queries
Client
Database Server
Results
Database Processing
• Querying database
• Updating database:
– 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
Data Consumer
Adapter
Dataset
WinForm
Connection
Command
WebForm
Reader
ADO.NET 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
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 access to
data stored in diverse information sources, or data stores.
– Access
• SQL Server Provider
• Oracle Provider
– Microsoft’s .NET data provider for Oracle
Using ODBC
• Windows XP:
• Control Panel /Administrative Tools/DataSource(ODBC)
• Creating data source names
– System DSN
• Demo:
– Access:
Connecting to Database from Visual
Studio
• Adding connection:
– Tools/Connect to database
• Data Source
–
–
–
–
ODBC
OLE DB (Access)
SQL Server
Oracle, etc.
• Server Explorer
– Data connections: Right click data connection
• Add Connection
– Tables, Views
• Create new SQL Server Database
Adding Data Source to VB Project
• Data/Add New Data Source
– Database:
• Using the connections
– Service
– Object
• LINQ To SQL Server
How to create ADO.Net objects?
• Automatically generated when creating
data bound 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 binding: 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 control’s Data Source and
Data Member to bind the data.
Creating Data Bound Form
• Creating a form with ADO.Net objects and databound 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 table’s name:
• Datagrid view
• Details
– Drag the table to form.
Items Added to the Form
• 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(ByVal sender
As System.Object, ByVal e As System.EventArgs) Handles
CUSTOMERBindingNavigatorSaveItem.Click
Me.Validate()
Me.CUSTOMERBindingSource.EndEdit()
Me.CUSTOMERTableAdapter.Update(Me.SalesDBDataSet.CUSTOMER)
End Sub
Private Sub Form3_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
'TODO: 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, Save buttons from
navigator bar.
Hierarchical Forms
• Parent table/Child table
– Add parent table and child table to Data Source
– Parent table uses detail view and child table uses
dataGrid view
– Drag the parent table and the child table to the form.
– RightClick Dataset object to choose Edit in Dataset
Designer
– With the designer, right click the parent table and
choose Add/Relation
– Change dataGrid’s 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 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
Creating 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