Database & Image

[Jaime Herrero]

Hi!

I have a SQLserver table with a field whose datatype is Image.
I have a form with a Picture bound to this
table field.
When I´m in AddNew or Update and I load the Image
(LoadPicture) I can see my image in the form.
But when i update the register, the image is lost.
How can I avoid this? Maybe Must I load the image with GetChuck?

Thank you

[cniquille]

I give you a class that I have created to do this work. I use it on SQL 7.0


VERSION 1.0 CLASS
BEGIN
MultiUse = -1 'True
Persistable = 0 'NotPersistable
DataBindingBehavior = 0 'vbNone
DataSourceBehavior = 0 'vbNone
MTSTransactionMode = 0 'NotAnMTSObject
END
Attribute VB_Name = "CImageSql"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = True
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = True
Option Explicit

Const BLOCK_SIZE = 16384

Public Sub SQLToFile(fld As ADODB.Field, ByVal FName As String, _
Optional FieldSize As Long = -1, _
Optional Threshold As Long = 1048576)
'
' Assumes file does not exist
' Data cannot exceed approx. 2Gb in size
'
Dim F As Long, bData() As Byte, sData As String
F = FreeFile
Open FName For Binary As #F
Select Case fld.Type
Case adLongVarBinary
If FieldSize = -1 Then ' blob field is of unknown size
WriteFromUnsizedBinary F, fld
Else ' blob field is of known size
If FieldSize > Threshold Then ' very large actual data
WriteFromBinary F, fld, FieldSize
Else ' smallish actual data
bData = fld.Value
Put #F, , bData ' PUT tacks on overhead if use fld.Value
End If
End If
Case adLongVarChar
If FieldSize = -1 Then
WriteFromUnsizedText F, fld
Else
If FieldSize > Threshold Then
WriteFromText F, fld, FieldSize
Else
sData = fld.Value
Put #F, , sData ' PUT tacks on overhead if use fld.Value
End If
End If
End Select
Close #F
End Sub

Private Sub WriteFromBinary(ByVal F As Long, fld As ADODB.Field, _
ByVal FieldSize As Long)
Dim Data() As Byte, BytesRead As Long
Do While FieldSize <> BytesRead
If FieldSize - BytesRead < BLOCK_SIZE Then
Data = fld.GetChunk(FieldSize - BLOCK_SIZE)
BytesRead = FieldSize
Else
Data = fld.GetChunk(BLOCK_SIZE)
BytesRead = BytesRead + BLOCK_SIZE
End If
Put #F, , Data
Loop
End Sub

Private Sub WriteFromUnsizedBinary(ByVal F As Long, fld As ADODB.Field)
Dim Data() As Byte, Temp As Variant
Do
Temp = fld.GetChunk(BLOCK_SIZE)
If IsNull(Temp) Then Exit Do
Data = Temp
Put #F, , Data
Loop While LenB(Temp) = BLOCK_SIZE
End Sub

Private Sub WriteFromText(ByVal F As Long, fld As ADODB.Field, _
ByVal FieldSize As Long)
Dim Data As String, CharsRead As Long
Do While FieldSize <> CharsRead
If FieldSize - CharsRead < BLOCK_SIZE Then
Data = fld.GetChunk(FieldSize - BLOCK_SIZE)
CharsRead = FieldSize
Else
Data = fld.GetChunk(BLOCK_SIZE)
CharsRead = CharsRead + BLOCK_SIZE
End If
Put #F, , Data
Loop
End Sub

Private Sub WriteFromUnsizedText(ByVal F As Long, fld As ADODB.Field)
Dim Data As String, Temp As Variant
Do
Temp = fld.GetChunk(BLOCK_SIZE)
If IsNull(Temp) Then Exit Do
Data = Temp
Put #F, , Data
Loop While Len(Temp) = BLOCK_SIZE
End Sub

Public Sub FileToSQL(ByVal FName As String, fld As ADODB.Field, _
Optional Threshold As Long = 1048576)
'
' Assumes file exists
' Assumes calling routine does the UPDATE
' File cannot exceed approx. 2Gb in size
'
Dim F As Long, Data() As Byte, FileSize As Long
F = FreeFile
Open FName For Binary As #F
FileSize = LOF(F)
Select Case fld.Type
Case adLongVarBinary
If FileSize > Threshold Then
ReadToBinary F, fld, FileSize
Else
Data = InputB(FileSize, F)
fld.Value = Data
End If
Case adLongVarChar
If FileSize > Threshold Then
ReadToText F, fld, FileSize
Else
fld.Value = Input(FileSize, F)
End If
End Select
Close #F
End Sub

Private Sub ReadToBinary(ByVal F As Long, fld As ADODB.Field, _
ByVal FileSize As Long)
Dim Data() As Byte, BytesRead As Long
Do While FileSize <> BytesRead
If FileSize - BytesRead < BLOCK_SIZE Then
Data = InputB(FileSize - BytesRead, F)
BytesRead = FileSize
Else
Data = InputB(BLOCK_SIZE, F)
BytesRead = BytesRead + BLOCK_SIZE
End If
fld.AppendChunk Data
Loop
End Sub

Private Sub ReadToText(ByVal F As Long, fld As ADODB.Field, _
ByVal FileSize As Long)
Dim Data As String, CharsRead As Long
Do While FileSize <> CharsRead
If FileSize - CharsRead < BLOCK_SIZE Then
Data = Input(FileSize - CharsRead, F)
CharsRead = FileSize
Else
Data = Input(BLOCK_SIZE, F)
CharsRead = CharsRead + BLOCK_SIZE
End If
fld.AppendChunk Data
Loop
End Sub




Christian Niquille