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Apostrophe Error in SQL matching

Posted on 2004-08-11
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Last Modified: 2013-12-25
I have used code similar to the following to search for matching records in a database, and it works well, providing a narrowing list of matches as the 'Search' texts gets longer.

Variables FtExt1 and FtExt2 are the contents of the two Search text boxes, and the code is called to update the Recordset after every change in either text box.

The problem occurs when the Search text includes an APOSTROPHE eg O'Carrol. This is because SQL uses the apostrophe for its' own purposes, and this extra apostrophe destroys the logic of the SQL.

If the user types an Apostrophe, the program crashed, until I added code to trap this character


    SQL = "Select [ID], [Title], [Name], Age FROM Entrants WHERE ([Title] like '" & FtExt1 & "' OR [Title] is Null) AND ([Name] like '" & FtExt2 & "') ORDER BY 3,2;"
    MatchingRs.Open SQL, SMConn, adOpenKeyset, adLockReadOnly

This problem is not a large one, but does restrict the scope of my 'Find' routine to some extent.

Is there a way to include the apostrophe in the SQL without crashing it

thanks

nedwob
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Question by:nedwob
8 Comments
 
LVL 69

Assisted Solution

by:Éric Moreau
Éric Moreau earned 30 total points
ID: 11774001
You have to double it:

 SQL = "Select [ID], [Title], [Name], Age FROM Entrants WHERE ([Title] like '" & replace(FtExt1, "'","''") & "' OR [Title] is Null) AND ([Name] like '" & replace(FtExt2,"'", "''") & "') ORDER BY 3,2;"
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LVL 6

Assisted Solution

by:bkthompson2112
bkthompson2112 earned 30 total points
ID: 11774007
Hi nedwob,

Use 2 apostrophes.  ''
When the user enters an apostrophe add another to the search string.

bkt
0
 
LVL 29

Accepted Solution

by:
leonstryker earned 80 total points
ID: 11774575
You may want to use a function to do this to all of your SQl string before passing them to the database.  Here is sample function which does it:

http://www.experts-exchange.com/Programming/Programming_Languages/Visual_Basic/VB_Databases/Q_20602507.html

Leon
0
 
LVL 6

Assisted Solution

by:PePi
PePi earned 50 total points
ID: 11774804
use replace like so:


SQL = "Select [ID], [Title], [Name], Age FROM Entrants WHERE ([Title] like '" & Replace(FtExt1,"'","''") & "' OR [Title] is Null) AND ([Name] like '" & Replace(FtExt2,"'","''") & "') ORDER BY 3,2;"


in the replace function, the second parameter is a double quote, single quote, double quote
the third parameter is a double quote,  a single quote, another single quote then a double quote.

it's very hard to see the difference of these single & double quotes just by looking at it. hope this helps
0
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LVL 8

Assisted Solution

by:mladenovicz
mladenovicz earned 70 total points
ID: 11781918
Public Function m_PrepareQueryParams(str As String) As String
Dim sRes As String
   
    sRes = str
   
    sRes = Replace(sRes, "[", "[[]")
    sRes = Replace(sRes, "*", "[*]")
    sRes = Replace(sRes, "?", "[?]")
    sRes = Replace(sRes, "#", "[#]")
    sRes = Replace(sRes, "%", "[%]")
    sRes = Replace(sRes, "_", "[_]")
    sRes = Replace(sRes, "'", "''")
   
    m_PrepareQueryParams = sRes
   
End Function
0
 

Author Comment

by:nedwob
ID: 11784958
Thanks for the comments. I will look at them and come back to award the points in a day or two.

nedwob
0
 
LVL 18

Assisted Solution

by:JR2003
JR2003 earned 40 total points
ID: 11826298
I use a function called DBStr and call it with every string I put into some sql.
Just paste the function into a module and call it from all the literals you put in sql.
It works a treat...

'Example Usage:
===========

 SQL = "Select [ID], [Title], [Name], Age FROM Entrants WHERE ([Title] like '" & DBStr(FtExt1) & "' OR [Title] is Null) AND ([Name] like '" & DBStr(FtExt2) & "') ORDER BY 3,2;"



'Function:
'======

Public Function DBStr(sIn As String) As String

    Dim tmp As String
    Dim i As Long
    Dim j As Long
   
    If Len(sIn) <> 0 Then
        j = 1
        Do
            i = InStr(j, sIn, "'")
            If i = 0 Then Exit Do
            tmp = tmp & Mid$(sIn, j, i - j) & "''"
            j = i + 1
        Loop
        DBStr = tmp & Mid(sIn, j)
    End If
   
End Function

0
 

Author Comment

by:nedwob
ID: 11831908
Thanks to all. I have increased the points and will split according to the input or usefulness to me.
0

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