Transcript Visual Basic Database Access

Introduction to ADO.Net and Visual
Studio Database Tools
ISYS 512
Database Processing
• Querying database
• Updating database:
– Insertion, deletion, modification
Steps to Retrieve Data
• Establishes a connection to the database.
• Executes query commands against the
database.
– SQL Select commands
• Process the returned data.
Steps to Update Data
• Establishes a connection to the database.
• Executes update commands against the
database.
– SQL Insert, Delete, Update commands
• Receive confirmation of completion.
ADO.Net: Connected and Disconnected
Data Processing
• The ADO.Net environment can be categorized
into connected and disconnected environments.
– A connected environment requires a constant
connection to transfer data between the client
application and the data source.
– A disconnected environment retrieves data and
performs modification without a constant connection
to the data source.
ADO.Net Classes
ADO.Net Classes and Data Consumer
Ado.Net
Adapter
Connection
Dataset
Data Consumer
Command
WinForm
DataReader
WebForm
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.
– MS Access (accdb)
• SQL Server Provider
• Oracle Provider
• Etc.
Using ODBC
• Windows 7:
• Control Panel /Administrative Tools/DataSource(ODBC)
• Three types of data source names, DSN
– User DSN: usable only by you and only on the machine
currently using.
– System DSN: Any one using the machine can use.
– File DSN: Can be copied and used by other computers
with the same driver installed.
• Note: For 32 bit software, you have to open the
ODBC panel from
C:\Windows\SysWOW64\odbcad32.exe
Define an ODBC DSN for Access
Database
• Download: SalesDB2011.accdb
• Open ODBC Window
• Define a System DSN to SalesDB2011 and
name it: MySalesData
SQL Server Express/
SQL Server Express LocalDB
• SQL Server Express is available free from
Microsoft, but it requires more computer
resources.
• SQL Server Express LocalDB is a lightweight version of SQL Server Express that is
already installed with VS 2012, and it does not
bring heavy workload on development
machines
VS Database Tools
• View/Server Explorer:
– For connection to ODBC data sources, OleDB to
MS Access, and SQL Server Express
• View/SQL Server Object Explorer
– For connection to SQL Server LocalDB
Connect to Access Database using OLE DB
• From Server Explorer, right-click Add Connection:
– Microsoft Access Database File (OLE DB)
– Browse for database
– Test Connection
• Tools/Connect to database
Connect to Access Database using ODBC
• From Server Explorer:
–
–
–
–
–
right-click Add Connection
Click Change
Microsoft Access ODBC Data source
Select DSN from the dropdown list
Test Connection
To Start SQL Server Express LocalDB
• View/SQL Server Object Explorer
• Point to SQL Server and Right-click:
– Add SQL Server
• Connect to Server
– Serve name: (localdb)\v11.0
– Connect
Lab: Creating a LocalDB
Database
• Database Name: MyDept
• Tables:
– Department:
• DID, Dname, Office
– Employee
• EID, Ename, Sex, Salary, HireDate, DID
To Add a New Database
• Open the LocalDB node
• Right-click Databases
– Add new database
• Enter database name
– Example: MyDept
To Add a New Table: Department
• Open the Database node: Open the MyDept node
• Right-click Tables and select: Add New Table
• Change the table name to Department
– CREATE TABLE [dbo].[Department]
• Click Update; then click Update Database
To Add Records
• Open the Tables node
• Right-click the table name (Department)
and select View Data
To Modify Table Design
• Point and right-click the table name:
– Select: View/Designer
• Change the CREATE TABLE command
• Or Change the design with the designer
Add Employee Table
• Right-click Tables and select Add Table:
– EID, Ename, Sex, Salary, HireDate, DID
Working with SQL Server Express
• Starting SQL Server:
– Control Panel/Administrative Tools
/Services/SQLServer(SQLExpress)
• SQL Server database file extension: mdf
• Default database folder:
– A SQL Server file: testSQLServer.mdf
– C:\Program Files\Microsoft SQL
Server\MSSQL10.SQLEXPRESS\MSSQL\DATA\testSQLServer.mdf
Creating SQL Server Database
• From Server Explorer, right click data connection
and choose:
• Create new SQL Server Database
• Server name:
– LocalServerName\SQLExpress
– Ex: David-PC\SQLExpress
• Add new table: Right click Tables and choose Add
New Table
– Define table’s fields
• Add rows: Right click the table name and choose
Show table data.
Create a New SQL Server
Database: EmployeeDB
• Add a new table: EmployeeTable
–
–
–
–
–
EID
Ename
Sex
Salary
HireDate
• Enter data
Char 10
Char 30
Char 1
Numeric (10,2)
Date
Three Ways to Create ADO.Net Objects
• 1. Automatically generated when
creating data bound form.
– Form wizard
• 2. Using Data Adapter Wizard
• 3. Using code:
– Example:
– string strConn = "Provider=Microsoft.ACE.OLEDB.12.0;Data
Source=C:\\SalesDB2007.accdb";
– OleDbConnection objConn = new OleDbConnection(strConn);
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.
Automatically Generating Data
Bound Form
• Creating a form with ADO.Net objects and databound controls to display and update information in
a dataset.
• Step 1: Add a new data source:
• Step 2: Select controls for table fields:
– Click the dropdown list next to the table’s name:
• Datagrid view
• Details
• Step 3: Drag the table to form.
Add Data Source
• Data Source window:
– View/Other windows/Data Source
• Add New Data Source
– From Dataset
– Select connection
– Select tables
Data Bound Form Examples
• Using the LocalDB database MyDept, show
records of the Employee table:
– with dataGridView
– with detail view
Items Added to the Form
• Table Adapter: click smart tag
– Add query
– Preview data
• Dataset:
– Edit in dataset designer
• Binding Source: It is an object that keeps track of
position (the current row) of a data source.
– Preview data
• Code view:
– Form load event:
• Adapter’s Fill command
Other Data Form Demos
• DataGrid View
• Add /Modify/Delete records.
• Read only form:
– Delete AddNew, Delete, Save buttons from
navigator bar.
Hierarchical Forms:
Department/Employees
• 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 object’s smart tag 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: Employee table form with EID listbox
and displays selected employee information in
textboxes.
– Choose detail view for the Employee table.
– Click the dropdown list next to the EID field and click
ListBox
– Drag the Employee table to the form.
– Bind the EID field to the BindingSource:
• Activate the Property window and click the listbox
• Set the DataSOurce property to BindingSource
• Set the Display Member property to EID
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
Demo: Add Data Source from
OleDB and ODBC Data source
Data Adapter Wizard – 2nd Level
of Using ADO.Net
• Configure Data Adapter and generating a dataset:
– From the Data tab of the ToolBox, Drag
OledbDataAdapter 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 in
Toolbox’s Data tab , right click ToolBox Data
Tab and select Choose Item; then select
OleDbDataAdapter 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 Fill
method to load the dataset:
• OleDbDataAdapter1.Fill(DataSet11);
• Note 1: No navigation capability
• Note 2: View adapter’s properties and see
the SQL commands.
Creating a Form with Bound
Textboxes
• Configure Adapter and generate dataset.
• Select textbox’s Data Bindings property:
– Text: choose field from bindingSOurce object
• In the Form Load event, use Adapter’s Fill
method to load the dataset:
• OleDbDataAdapter1.Fill(DataSet11)
• Note: No navigation capability
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 0based 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 to
set its DataSource and Data Member properties to
the dataset object and table object.
• Set control’s DataBinding property to the
BindingSource 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 void button3_Click(object sender, EventArgs e)
{
bindingSource1.AddNew();
}
Save button: Use BindingSource EndEdit method and
Adapter’s Update method:
private void button4_Click(object sender, EventArgs e)
{
bindingSource1.EndEdit();
oleDbDataAdapter1.Update(dataSet2.CUSTOMER);
}
Binding ListBox
• Example: Bind Customer Table’s 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 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
• textBox3.Text = listBox1.SelectedValue.ToString();
– To display other fields:
• VB with late binding
– Textbox1.text = ListBox1.SelectedItem(“Cname”)
• C# does not support late binding:
No!
ListBox SelectedItem Property:
(Works for VB)
• How to display the selected record in unbound
textbox?
• After binding 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 object’s properties,
methods. Ex. System.Data.OleDbDataAdapter
Unbound Textbox:
Navigate from Dataset to Table;
from Table to Row and Field
textBox3.Text =
dataSet41.Tables["employee"].Rows[listBox1.SelectedIndex
][1].ToString();
textBox4.Text =
dataSet41.Tables["employee"].Rows[listBox1.SelectedIndex
]["Salary"].ToString();
Working with SQL Server Data
Adapter
• From the Data tab:
– Choose: SQLDataAdapter
– (If you don’t see it, right-click the Data tab and
select Choose Item. Then select it from the
.Net components)
DataSet and Data Adapter
• 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.
– It is an object with SQL Select, Insert, Update and
Delete commands.
Creating Parent/Child Form Using
DataAdapter Wizard
• Add two DataAdapters to the form: one for the parent
table 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; add
dataGridView and bind its datasource property to the
relation.
• Add navigation button’s using parent table’s
BindingSource object.