vb net data access sf 10

8/10/2019 Vb Net Data Access Sf 10

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Introduction to ADO.Net, VB.Net

Database Tools and Data Binding

ISYS 512



Database Processing

• Querying database

• Updating database:

– Insertion, deletion, modification



Steps to Retrieve Data

• Establishes a connection to the database.

• Executes commands against the database.

– SQL Select commands

• Store data results.



A Simplified View of ADO.Net

Objects

Ado.Net

Data Provider

Connection

Adapter

Command

Reader

DatasetData Consumer

WinForm

WebForm

SQL Updates

Results of SQL Selects



ADO.NET Objects

• Connection Object: Represent a connection to thedatabase.

• Command Object: The command object allows usto 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 todata stored in diverse information sources, or data stores.

– Access

• SQL Server Provider

• Oracle Provider

– Microsoft’s .NET data provider for Oracle

• Etc.



Demo: SAS Reading ODBC Data

• proc sql;

• connect to odbc (dsn=MySalesDB2007);

• Create table sasuser.TEST

• As select * from connection to ODBC

• (select * from customer);

• disconnect from odbc;

• quit;

• proc sql;

• select * from sasuser.test;



VB.NET Database Tools

• Add a new connection to database: – Database connection:

• Tools/Connect to database

– Add Connection

– Server Explorer

• Data connections: Right click data connection

– Add Connection

» Tables, Views

• Create new SQL Server Database

• Add a new data source: – Data/Add New Data Source



Types of Data Source



Working with SQL Server

• Starting SQL Server:

– Control Panel/Administrative

Tools/Services/SQLServer

• SQL Server database file extension: mdf

• Default database folder:

– A SQL Server file: testSQL08.mdf

– C:\Program Files\Microsoft SQL

Server\MSSQL.1\MSSQL\Data\testSQL08.mdf



Creating SQL Server Database

• From Server Explorer, right click data connectionand choose:

• Create new SQL Server Database

• Server name:

– LocalServerName\SQLExpress• Add new table: Right click Tables and choose Add

New Table

– Define table’s fields

• Add rows: Right click the table name and chooseShow table data.

• Note: After creating the database, you may createan ODBC DSN to connect to it.



Create a New SQL Server

Database: EmployeeDB• Add a new table: EmployeeTable

– EID Char 10

– Ename Char 30

– Sex Char 1

– Salary Numeric (10,2)

– HireDate Date

• Enter data



How to create ADO.Net objects?

• Automatically generated when creatingdata 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 afield 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 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 table’s name: • Datagrid view

• Details

– Drag the table to form.



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(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 fromnavigator 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 usesdataGrid view

– Click Dataset object’s smart tag to choose Edit inDataset Designer

– With the designer, right click the parent table andchoose Add/Relation

– Change dataGrid’s DataSource property to the relation.



Detail Form with Bound ListBox

• Example: Customer table form with CID listboxand displays selected customer information intextboxes.

– 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 dataforms:

– DisplayInfo

– Enter New

– Modify

– Exit



Data Adapter Wizard – 2nd Level

of Using ADO.Net• Configure Data Adapter and generating a dataset:

– From the Data tab of the ToolBox, DragOledbDataAdapter to the form.

– Use the Data Adapter Wizard to configure the Adapter. – Right Click the Adapter to preview data and create

dataset.

• Note: If OledbDataAdapter is not listed inToolbox’s Data tab , right click ToolBox DataTab and select Choose Item; then selectOleDbDataAdapter from .Net Framework components.



Creating a Form with Bound DataGridView

• Configure Adapter and generate dataset.

• Bind DataGridView control to the table:

– Data Source property:• DataSet

– Data Member property

• A table in the dataset

• In the Form Load event, use Adapter’s Fillmethod to load the dataset:

• OleDbDataAdapter1.Fill(DataSet11)

• Note 1: No navigation capability

• Note 2: View adapter’s properties and seethe SQL commands.



Using BindingContext to Navigate

Records

• BindingContext: It 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. Twouseful properties:

– Position property: is the index of the current row. The

index is a 0-based index, the first record has a position

of 0. – Count property: The number of rows in the data source.



MoveNext and MoveLast Example

• MoveNext: – Me.BindingContext(DataSet21, "customer").Position += 1

• MoveLast: – Me.BindingContext(DataSet21, "customer").Position =

Me.BindingContext(DataSet21, "customer").Count -1

• How to MovePrevious and MoveFirst?

• Note: The Position property takes care of the end of fileautomatically.

• Note: Me.BindingContext(DataSet21, "customer") returnsa CurrencyManager object.



Using BindingSource Object to Do

the Binding and Navigation

• 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

– AddNew – AllowEdit

– EndEdit

– Current

– RemoveCurrent



Bind Controls to BindingSource

Object• Configure Adapter and generate dataset.

• Add BindingSource object to the form

• Use BindingSource object’s property window toset its DataSource and Data Member properties tothe dataset object and table object.

• Set control’s DataBinding property to theBindingSource object.



Use BindingSource Object’s

MoveNext, MovePrevious Methods• Add a MoveNext button

– BindingSource1.MoveNext()

• Add a MovePrevious button:

– BindingSource1.MovePrevious()



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.Click

BindingSource1.AddNew()

End Sub

Save button: Use BindingSource EndEdit method and

Adapter’s Update method:

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As

System.EventArgs) Handles Button2.Click

BindingSource1.EndEdit()

OleDbDataAdapter1.Update(DataSet21.CUSTOMER)

End Sub



Binding ListBox

• Example: Bind Customer Table’s CID field

to a listbox.

– Create a Adapter for Customer table , andgenerate the dataset.

– Add ListBox and set binding properties:

• Data Source: Customer table• Display Member: Field to display in the listbox.

• 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.

• Unbound 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 unboundtextbox?

• After binding to a data source, this property return aDataRowView 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 object’s properties,methods. Ex. System.Data.OleDbDataAdapter



DataSet and Data Adapter

• DataSet Object: A DataSet object can hold severaltables and relationships between tables.

• DataAdapter: This the object used to pass data between the database and the dataset.

– It is an object with SQL Select, Insert, Update andDelete commands.

i / hild i



Creating Parent/Child Form Using

DataAdapter Wizard

• Add two DataAdapters to the form: one for the parenttable and one for the child table.

• Use the parent table’s DataAdapter to generate a

dataset; then use the child table’s DataAdapter to

generate the child table into the same dataset.

• Open dataset’s designer and right-click the parent table

and choose Add/Relation to add a relation.

• Add and bind textboxes to the parent table; adddataGridView and bind its datasource property to the

relation.

• Add navigation button’s using BindingSource object.

vb net data access sf 10

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