Using SQL Server Express with Visual Basic.NET
Professor Ralph Westfall April 2011
Sample Code
Create Visual Basic.NET Project
Start>All Programs>Microsoft Visual Studio 2008
Click Project link after Create: on left side
Expand Visual Basic>click Windows>Windows Forms Application>rename as Olympics-SQL>
OK
File>Save All>[check Create Directory for solution if available>]browse to the
Desktop>Save
File>Exit
SQL Server Express Versions
You may get SQL Server Express 2005
when you install Visual Studio Professional 2008
If so, you should also install SQL Server Express 2008 to go with it (download the x64 version for Vista, or the x86 one for other Windows
versions)
If you can avoid installing SQL Server Express 2005 when installing Visual Basic, it will make it easier to install SQL Server Express 2008
Set Up SQL Server Express
I was having trouble connecting with SQL Server 2008 until I did the following
See the following slide if these menu choices aren’t available
Start>All Programs>Microsoft SQL Server 2008>Configuration Tools>SQL Server
[Surface Area] Configuration Manager
click lower link that says Surface Area
Configuration for Services and Connections
Click Remote Connections>Local and remote connections>Using TCP/IP only>OK
Set Up SQL Server Express
I installed a later version and it was like this:
Start>All Programs>Microsoft SQL Server 2008>Configuration Tools>SQL Server
Configuration Manager
Click SQL Server Services>if Log On As is not LocalSystem, right-click SQL Server
(SQLEXPRESS)>Properties>Built-in account:>select LocalSystem>OK>Yes
Then close Tools>SQL Server Configuration Manager
Create a SQL Server Database
Start>All Programs>Microsoft SQL Server 2008>SQL Server Management Studio>OK
Be sure Windows Authentication is being used, write down the Server name:>click Connect
Expand server name and then Databases in Object Explorer window on lower left
if get error message, minimize, click refresh button at top of Object Explorer and try again
problem may be a database that wasn't detached before deletion
right-click Databases>New Database>type Olympics as Database name:>OK
Import Data
File for following instructions: olympics.csv
Opens in Excel, save from there>Yes (to keep CSV format, then No on save changes)
Right-click Olympics (database name)>
Tasks>Import Data>Next>
select Flat File Source>Browse and select Files of type: CSV files (*.csv) to get
olympics.csv>select Format: Delimited>Next>
(use Format: Ragged right for *.txt files)
Next >Next (Use Windows authentication)>
Next> click Edit Mappings button
Modify Fields, View Data
Change field names and properties in Destination column:
1st column = Country, Data Type = nchar(20)
Next three rows should be Gold, Silver, Bronze, each with Data Type of int
Last row should be Pop, with Data Type of decimal with Precision = 7, Scale = 2>OK
Create destination table should be checked
Next>Next>Next>Finish> Close
Modify Database Structure
Expand database name in Object Explorer
Right-click Olympics>Refresh
Expand Tables>right-click dbo.olympics>Design
Set up key field
Right-click first row>Insert Column>make name be ID>change Data Type to int>unclick Allow nulls (but leave checked for other fields)
Right-click ID>Set Primary Key
In Column properties below, expand Identity
Specification, set (IsIdentity) as Yes, set Identity Seed as 100 or 101 (makes all keys same length)
Saving New Database Table
File>Save Olympics>Yes (ignore warnings)
If still can’t save: Tools>Options>Designers>
uncheck Prevent saving changes … >OK and then try to save again
Right-click table name>Edit Top 200 Rows
Verify that proper data is in right-most fields (integers in Bronze, decimals in Pop
Edit data if necessary to fix problems
Field Length Data Types
int 4 bytes, values range from ±2 billion
char is number of bytes in parentheses
Reserves that much space for fields
nchar is for international (Unicode) applications
varchar is for variable length text fields
Only uses as much space as is needed for each field (saves space in database)
Use nvarchar for international applications
decimal (x, y) is more accurate than float for decimal values (x=total digits, y=decimals)
Can have missing values with Allow Nulls
Never allow ID field value to be missing!
Detach Database
Right-click Olympics (database name) in Object Explorer>Facets>select and copy PrimaryFilePath>OK
Open File Explorer and paste that path into address box
Close the Design and/or Edit windows on the right of Management studio>right-click
Olympics>Tasks>Detach>check Drop>OK
Close Management Studio
Move SQL Server Database
Select and Cut Olympics.mdf and
Olympics_log.ldf files in Windows Explorer
Create a new folder named cis338 on the C:\
drive
Then paste the two files into that directory
Microsoft Access 2007
File for following instructions: olympics.csv
Start>All Programs>Microsoft Office>
Microsoft Office Access 2007
Click Blank database>name it
olympics.accdb>browse to C:\cis338 [thanks
to Rafael Robles] folder and Save the file in
that directory>Click Create
Microsoft Access Data Fields
Click External Data tab>click Import text file icon>Import the source data into a new
table>browse to olympics.csv file>OK>
Delimited>Next>Comma>Next>
Change Field Names to Country, Gold, Silver, Bronze, Pop
Make Country be Text, the medals be Integer, and Pop be Double>Next
Let Access add primary key>Next
Leave Table name as Olympics>Finish>Close
Close Table1>Exit Access
Restart Visual Basic Project
Double click the Olympics-SQL.sln file in Olympics-SQL folder on the Desktop to restart Visual Studio 2008
Click Form1 in Solution Explorer and then the icon to view it in the designer window
Right-click Form1 in designer window>
Properties
Change (Name) to frmUI
Change Text to Olympics Data
Click and drag right side of Form to make it
wider
Add Controls
Go to Form Designer window and drag the
following onto the following locations on Form:
Upper left: Label, set Text as Country
Under Label: ComboBox, (Name) cboCountries, change DropDownStyle to Simple, Sorted to True, Font to Courier New
To right of 1st Label: Label, set Text as # of Golds
Under 2nd Label: ListBox, (Name) lstGolds
Click Items (Collection) in lstGolds and type 1 through 10 on separate rows>OK
More Controls
Add a CheckBox to right of 2
ndLabel with (Name) = chkPop, Text = Populous?
Put * separate Buttons below each control
Name them btnCountry, btnGolds, btnPop and set the Text for each as Select
Add two more Buttons: btnClear and btnExit, with Text of Clear and Exit
* grammar error (superfluous ‘a’) spotted by Cameron Berlino
Output ListBox
Add another ListBox stretching across the bottom of the Form, (Name) lstOutputs
Add label over it: Text=Countries G S B Pop
Set ListBox Font to Courier New so that outputs will line up in columns
Align controls and Labels to look professional
Add a Module: Data Tier
Project>Add Module>Name: DataSS.vb>OK
Type: Imports System.Data.SqlClient above the Module statement
Imports System.Data.OleDb 'Use for MS Access
Below the Module statement, type:
Private pads() As Integer = {19, 3, 3, 3, 7}
Public Function AcquireData(ByVal queryStr As String, ByVal startSize As Integer) As ArrayList
Then hit Enter to generate End Function
Add Variable Declarations
Type the following in the new Function
Dim alsData As ArrayList
Dim da As SqlDataAdapter '*
Dim ds As DataSet
Dim con As SqlConnection '**
Dim dr As DataRow
Dim dc As DataColumn Dim rowData As String
'* OleDbDataAdapter for Access '** OleDbConnection for Access
Add Code for Database
Below the declarations, type following lines:
ds = New DataSet
con = New SqlConnection 'OleDbConnection
con.ConnectionString = "server=(local)\SQLEXPRESS;
AttachDbFilename=" & "C:\cis338\Olympics.mdf;" &
"Integrated Security=True;"
'or Olympics.dbo if that's the file type 'or con.ConnectionString =
"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" &
"C:\cis338\Olympics.accdb;" [thanks to Karla Lopez]
More Code for Database
con.Open()
da = New SqlDataAdapter(queryStr, con) 'OleDbDataAdapter
da.Fill(ds) 'da.Fill(ds, "Olympics")
Add Code to Load ArrayList
Next, type:
alsData = New ArrayList(startSize)
Dim i as Integer 'move up into other declations For Each dr In ds.Tables(0).Rows
rowData = ""
For Each dc In ds.Tables(0).Columns
rowData += Trim(dr(dc).ToString()).PadRight(pads(i)) '*
i += 1 Next
i = 0
alsData.Add(rowData) Next
* will need to use PadLeft for left padding numbers
Finish Function and Module
Type:
con.Close() da = Nothing
ds = Nothing Return alsData
Code the Form
Double-click the Form in the designer
Add the following declaration above the frmUI_Load Sub:
Private alsData As ArrayList
Add the following code to the frmUI_Load Sub
alsData = DataSS.AcquireData("select Country from Olympics order by Country", 80)
For Each item In alsData
cboCountries.Items.Add(Trim(item.ToString)) Next
Test the Data Tier and Form
Double click the Exit button on the Form and then put the word End in the generated Sub
Now run the code and make corrections if necessary
might be easier to just copy code from this PowerPoint over again where problems are found
and/or look at code/copy from Sample Code zip
Add a Module: Business Tier
Project>Add Module>name BizTier.vb>OK
Type code below the Module statement:
Private Const COUNTRY_FIELD As String = "
Country "
Private Const ALL_FIELDS As String = " * "
Private Const COUNTRY_COUNT As Integer = 80 'default ArrayList size
Private Const SIZE_FACTOR As Integer = 3 'for reducing ArrayList size for selections
Code a Function
Type the following below the declarations shown on previous slide:
Public Function GetData(ByVal whatData As
String, Optional ByVal whatCriteria As String =
"", Optional ByVal whatCompare As String = "=") As ArrayList
With cursor at end of above line, hit Enter to
generate End Function
Declare and Initialize
Type the following code within the Function:
Dim selectors As String Dim fromArg As String Dim orderArg As String Dim dataSize As Integer
Dim dataSizeSmaller As Integer Dim sqlStr As String = ""
selectors = " select Country "
fromArg = " from Olympics "
orderArg = " order by Country; "
Add Selection Code
Type:
dataSizeSmaller = CInt(COUNTRY_COUNT / SIZE_FACTOR) 'reduces default size
If whatData = "formLoad" Then
sqlStr = selectors & fromArg & orderArg dataSize = COUNTRY_COUNT
Else
selectors += ", Gold, Silver, Bronze, Pop"
dataSize = dataSizeSmaller
More Selection Code
Type:
If whatData = "country" Then
sqlStr = selectors & fromArg & " where
Country " & whatCompare & "'" & whatCriteria &
"'" & orderArg
dataSize = dataSizeSmaller ElseIf whatData = "population" Then
sqlStr = selectors & fromArg & " where Pop " & whatCompare & whatCriteria & orderArg
Finish Coding BizTier Module
Type:
ElseIf whatData = "golds" Then
sqlStr = selectors & fromArg & " where Gold "
& whatCompare & whatCriteria & orderArg End If
End If
Type the following just above End Function:
Console.WriteLine(sqlStr) 'for debugging
Return DataSS.AcquireData(sqlStr, dataSize)
Run the code and fix any compilation errors
Note: you won't get any output yet
Add Code for Form Selections
In the frmUI.vb file, add the following lines just below the Class statement at top of file:
Private selector As String Private comparer As String
Replace the line for loading the ArrayList
from the DataSQL Module in the frmUI_Load Sub (starts with alsData =) with :
alsData = BizTier.GetData("formLoad")
In the design window, double-click all of the
buttons to generate Subs for their code
Add Code to Clear Selections
Add a Sub to clear selections:
Private Sub ClearSelections()
lstOutputs.SelectedItem
= Nothing
lstGolds.SelectedItem = Nothing
cboCountries.SelectedItem = Nothing chkPop.Checked = False
End Sub
Put following into Sub for btnClear:
ClearSelections()
lstOutputs.DataSource = Nothing 'clears outputs
Add Country Selection Code
Put following into Sub to select countries:
If cboCountries.SelectedIndex = -1 Then
MessageBox.Show("Please select a country”) Else
selector =
cboCountries.SelectedItem.ToString.Replace("'", "''") 'single quote in 1st string, 2 single quotes in 2nd
lstOutputs.DataSource =
BizTier.GetData("country", selector, "=") lstOutputs.DataSource =
BizTier.GetData("country", selector, "=")
cboCountries.SelectedItem = selector 'restore this End If
Add Gold Medal Selections
Add the following code for btnGolds:
If lstGolds.SelectedIndex = -1 Then
MessageBox.Show("Please select number of gold medals")
Else
selector = lstGolds.SelectedItem.ToString comparer = "="
lstOutputs.DataSource =
BizTier.GetData("golds", selector, comparer) ClearSelections()
lstGolds.SelectedItem = selector End If
Add Large Population Selection
Add the following code for btnPop:
Dim bigPop As Boolean comparer = ""
bigPop = chkPop.Checked If bigPop Then
comparer = ">="
Else
comparer = "<"
End If
lstOutputs.DataSource =
BizTier.GetData("population", "100", comparer) ClearSelections()
chkPop.Checked = bigPop
Test and Fine Tune
Run the code and test all the buttons and selection possibilities
Be sure to verify that current selections stay visible but all others are cleared on each click
Verify that the outputs data is correct for each selection
Be sure that every Button gets clicked several times before you click the Exit button
Fine tune form appearance and usability
Appearance should be pleasing and professional
Form should be easy and “natural” to use
Form should be as compact as possible for user
