How to retreive image from acces database using datareader in VB.NET

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I use following code for storing image into access database and now I want to retrieve image through data reader please help me.

[removed duplicate code]

What I have tried:

VB

 Try

	Dim ms As New System.IO.MemoryStream
	Dim bmpImage As New Bitmap(stphoto.Image)

	bmpImage.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg)
	bytImage = ms.ToArray()
	ms.Close()

	Dim con As New OleDb.OleDbConnection
	Dim cmd As New OleDb.OleDbCommand
	Dim sqlstring As String
	Dim query As String
	sqlstring = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=bin\fee.accdb"
	con = New OleDb.OleDbConnection(sqlstring)
	con.Open()
	query = "INSERT INTO smaster ([sid],[sname],[fname],[add],[dob],[class],[college],[session],[cnumber],[gnumber],[photo]) Values (" & sidtxt.Text & ",'" & snametxt.Text & "','" & fnametxt.Text & "','" & addtxt.Text & "','" & dobpick.Value.ToShortDateString & "','" & classcombo.Text & "', '" & collegecombo.Text & "','" & sessioncombo.Text & "','" & mobtxt.Text & "','" & gnumbertxt.Text & "','@bytImage')"

	cmd = New OleDb.OleDbCommand(query, con)
	cmd.ExecuteNonQuery()

	studentid = sidtxt.Text
	studentname = snametxt.Text
	'code for opening add subject form

	Dim result As Integer = MessageBox.Show("Master Data Saved, Please Click OK for adding Subjects", "Student Data", MessageBoxButtons.OK)
	If result = DialogResult.OK Then
		addsub.Show()
	End If
Catch ex As Exception
	MessageBox.Show(ex.Message)
End Try

Posted 7-Sep-17 0:34am

Member 13397933

Updated 7-Sep-17 1:32am

Graeme_Grant

v2

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Graeme_Grant 7-Sep-17 6:44am

You pull it out the same way that you put it in.

Also, never concat SQL queries, always use parameters.

Member 13397933 7-Sep-17 12:03pm

Can you please explain through the code for the above problem, it will easy to understand for me.

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OriginalGriff · Answer 1 · 2017-09-07T01:32:00

Don't do it like that! Never concatenate strings to build a SQL command. It leaves you wide open to accidental or deliberate SQL Injection attack which can destroy your entire database. Use Parametrized queries instead.

When you concatenate strings, you cause problems because SQL receives commands like:

SQL

SELECT * FROM MyTable WHERE StreetAddress = 'Baker's Wood'

The quote the user added terminates the string as far as SQL is concerned and you get problems. But it could be worse. If I come along and type this instead: "x';DROP TABLE MyTable;--" Then SQL receives a very different command:

SQL

SELECT * FROM MyTable WHERE StreetAddress = 'x';DROP TABLE MyTable;--'

Which SQL sees as three separate commands:

SQL

SELECT * FROM MyTable WHERE StreetAddress = 'x';

A perfectly valid SELECT

SQL

DROP TABLE MyTable;

A perfectly valid "delete the table" command

SQL

--'

And everything else is a comment.
So it does: selects any matching rows, deletes the table from the DB, and ignores anything else.

So ALWAYS use parameterized queries! Or be prepared to restore your DB from backup frequently. You do take backups regularly, don't you?

And if you have used string concatenation to insert your images, well, you have another problem. They are all garbage, and you can't retrieve them...
See here: Why do I get a "Parameter is not valid." exception when I read an image from my database?[^] - the code is all in C#, but it's pretty simple and online convertes can change it if you can't cope.