Storing byte array in MySQL Blob with VBA - mysql

Question

Anybody have some VBA code that will store a byte array into a MySQL blob column?

Answer 1

Here is some code. Requires a reference to Microsoft Active Data Objects 2.x Library. It uses the OLE DB provider for MySQL (Might need to install that on the client machine).
Sub StoreBLOB(data() As Byte, key As Double)
'stores the BLOB byte array into the row identified by the key
'requires reference to Microsoft Active Data Objects 2.x Library
On Error GoTo handler:
Dim con As New ADODB.Connection
Dim rs As New ADODB.Recordset
Dim conStr As String
Dim strSQL As String
'have it return only the record you want to store your blob
strSQL = strSQL & "SELECT * FROM YOURTABLE WHERE KEY = " & key
'setup connection
conStr = conStr & "Provider=MySQLProv;"
conStr = conStr & "Data Source=mydb;"
conStr = conStr & "User Id=myUsername;"
conStr = conStr & "Password=myPassword;"
con.ConnectionString = conStr
con.Open
rs.Open strSQL, con, adOpenDynamic, adLockOptimistic
If rs.RecordCount > 1 Then
Err.Raise 1001, "StoreBLOB", "Too many records returned from dataset. Check to make sure you have the right key value"
Else
Err.Raise 1002, "StoreBLOB", "No Records found that match the key"
End If
rs.Fields("BLOBFIELDNAME").Value = data
rs.Update 'store the contents to the database
rs.Close
con.Close
Set rs = Nothing
Set con = Nothing
Exit Sub
handler:
Err.Raise 1003, "StoreBLOB", "Unexpected Error in StoreBLOB. Check that server is running"
End Sub

Answer 2

Assuming you are using ADO to access mysql, there's a KB article on the subject.

Answer 3

I have some code, I replicated the mysql_real_escape_string_quote C function in VBA so that one can escape the necessary characters and build your SQL as you would for regular text:
Function mysql_real_escape_string_quote(toStr() As Byte, fromStr() As Byte, length As Long, quote As String) As Long
mysql_real_escape_string_quote = 0
Dim CharMap() As Byte: CharMap = StrConv(String(256, 0), vbFromUnicode)
CharMap(0) = Asc("0"): CharMap(39) = Asc("'"): CharMap(34) = Asc(""""): CharMap(8) = Asc("b"): CharMap(10) = Asc("n"): CharMap(13) = Asc("r"):
CharMap(9) = Asc("t"): CharMap(26) = Asc("z"): CharMap(92) = Asc("\"): CharMap(37) = Asc("%"): CharMap(95) = Asc("_"):
Dim i As Long: Dim n As Long: n = 0
If length > UBound(fromStr) + 1 Then Exit Function
For i = 0 To length - 1 '---count escapable chars before redim---
n = n + 1
If CharMap(fromStr(i)) <> 0 Then n = n + 1
Next i
ReDim toStr(n - 1) As Byte
n = 0
For i = 0 To length - 1 '---test chars---
If CharMap(fromStr(i)) = 0 Then
toStr(n) = fromStr(i)
Else '---escape char---
toStr(n) = Asc(quote): n = n + 1
toStr(n) = CharMap(fromStr(i))
End If
n = n + 1
Next i
mysql_real_escape_string_quote = n
End Function
Function mysql_real_escape_string(InputString As String) As String
mysql_real_escape_string = ""
Dim toStr() As Byte: Dim fromStr() As Byte
fromStr = StrToChar(InputString)
If mysql_real_escape_string_quote(toStr, fromStr, UBound(fromStr) + 1, "\") = 0 Then Exit Function
mysql_real_escape_string = StrConv(toStr(), vbUnicode)
End Function
Function StrToChar(str As String) As Byte()
Dim ans() As Byte
ans = StrConv(str, vbFromUnicode)
ReDim Preserve ans(Len(str)) As Byte
ans(Len(str)) = 0
StrToChar = ans
End Function
Sub testit()
Dim toStr() As Byte: Dim fromStr() As Byte
fromStr = StrToChar("hello world's")
MsgBox (mysql_real_escape_string_quote(toStr, fromStr, UBound(fromStr) + 1, "\"))
MsgBox (mysql_real_escape_string("hello world's"))
For i = 0 To UBound(toStr)
Debug.Print i & " " & toStr(i)
Next i
End Sub
It's been optimized for large amounts of data without a ridiculous amount of conditionals (ifs).