Senin, 13 Agustus 2012

RE: [MS_AccessPros] Decreasing potential of "too many databases"

 

Connie-

The "too many databases" is a mystery. Me, I like to control what's going on,
so I always assign CurrentDb to an object variable and then make sure I clear it
before exit. With CurrentDb, you know you're always opening one more thread,
then killing it when you Set db = Nothing. I dunno what happens with a
reference to DBEngine.

John Viescas, author
Microsoft Office Access 2010 Inside Out
Microsoft Office Access 2007 Inside Out
Building Microsoft Access Applications
Microsoft Office Access 2003 Inside Out
SQL Queries for Mere Mortals
http://www.viescas.com/
(Paris, France)

-----Original Message-----
From: MS_Access_Professionals@yahoogroups.com
[mailto:MS_Access_Professionals@yahoogroups.com] On Behalf Of mrsgoudge
Sent: Monday, August 13, 2012 9:14 PM
To: MS_Access_Professionals@yahoogroups.com
Subject: Re: [MS_AccessPros] Decreasing potential of "too many databases"

John - That is code I copied from Allen Browne's site. Should I be changing
that? Any idea why Crystal would experience a decrease in the "cannot open
databases" messages using DBEngine(0)(0)?

Thanks!
Connie

--- In MS_Access_Professionals@yahoogroups.com, John Viescas <JohnV@...> wrote:
>
> Connie-
>
> Why are you using DBEngine(0)(0)? I would declare a db object As
DAO.Database,
> set it to CurrentDb, then release it in your exit code.
>
> John Viescas, author
> Microsoft Office Access 2010 Inside Out
> Microsoft Office Access 2007 Inside Out
> Building Microsoft Access Applications
> Microsoft Office Access 2003 Inside Out
> SQL Queries for Mere Mortals
> http://www.viescas.com/
> (Paris, France)
>
>
>
>
> -----Original Message-----
> From: MS_Access_Professionals@yahoogroups.com
> [mailto:MS_Access_Professionals@yahoogroups.com] On Behalf Of mrsgoudge
> Sent: Monday, August 13, 2012 8:03 PM
> To: MS_Access_Professionals@yahoogroups.com
> Subject: [MS_AccessPros] Decreasing potential of "too many databases"
>
> Good afternoon! Evening to you, John!
>
> I am working on getting rid of the "too many databases" message again and
doing
> my best to decrease the chances it will crop up. From some reading I've done,
> it seems that using the following function in a query could be a major
> contributor. Yes? when I do get the "too many databases" message debugging
> shows that it's usually stopped at this point.
>
> I'm considering putting the result in the underlying table. For example, once
> the listers are entered and the ListingContacts form is closed this would be
> entered for that listing in
> Listings.AllContacts.
>
> Input? I know this doesn't really follow the rules but I can only see the
> benefits.
>
> Thanks,
> Connie
>
>
> Public Function ConcatRelated(strField As String, _
> strTable As String, _
> Optional strWhere As String, _
> Optional strOrderBy As String, _
> Optional strSeparator = ", ") As Variant
> On Error GoTo Err_Handler
> 'Purpose: Generate a concatenated string of related records.
> 'Return: String variant, or Null if no matches.
> 'Arguments: strField = name of field to get results from and concatenate.
> ' strTable = name of a table or query.
> ' strWhere = WHERE clause to choose the right values.
> ' strOrderBy = ORDER BY clause, for sorting the values.
> ' strSeparator = characters to use between the concatenated
> values.
> 'Notes: 1. Use square brackets around field/table names with spaces or
> odd characters.
> ' 2. strField can be a Multi-valued field (A2007 and later), but
> strOrderBy cannot.
> ' 3. Nulls are omitted, zero-length strings (ZLSs) are returned
as
> ZLSs.
> ' 4. Returning more than 255 characters to a recordset triggers
> this Access bug:
> ' http://allenbrowne.com/bug-16.html
> Dim rs As DAO.Recordset 'Related records
> Dim rsMV As DAO.Recordset 'Multi-valued field
> recordset
> Dim strSQL As String 'SQL statement
> Dim strOut As String 'Output string to
> concatenate to.
> Dim lngLen As Long 'Length of string.
> Dim bIsMultiValue As Boolean 'Flag if strField is a
> multi-valued field.
>
> 'Initialize to Null
> ConcatRelated = Null
>
> 'Build SQL string, and get the records.
> strSQL = "SELECT " & strField & " FROM " & strTable
> If strWhere <> vbNullString Then
> strSQL = strSQL & " WHERE " & strWhere
> End If
> If strOrderBy <> vbNullString Then
> strSQL = strSQL & " ORDER BY " & strOrderBy
> End If
> Set rs = DBEngine(0)(0).OpenRecordset(strSQL, dbOpenDynaset)
> 'Determine if the requested field is multi-valued (Type is above 100.)
> bIsMultiValue = (rs(0).Type > 100)
>
> 'Loop through the matching records
> Do While Not rs.EOF
> If bIsMultiValue Then
> 'For multi-valued field, loop through the values
> Set rsMV = rs(0).Value
> Do While Not rsMV.EOF
> If Not IsNull(rsMV(0)) Then
> strOut = strOut & rsMV(0) & strSeparator
> End If
> rsMV.MoveNext
> Loop
> Set rsMV = Nothing
> ElseIf Not IsNull(rs(0)) Then
> strOut = strOut & rs(0) & strSeparator
> End If
> rs.MoveNext
> Loop
> rs.Close
>
> 'Return the string without the trailing separator.
> lngLen = Len(strOut) - Len(strSeparator)
> If lngLen > 0 Then
> ConcatRelated = Left(strOut, lngLen)
> End If
>
> Exit_Handler:
> 'Clean up
> Set rsMV = Nothing
> Set rs = Nothing
> Exit Function
>
> Err_Handler:
> MsgBox "Error " & Err.Number & ": " & Err.Description, _
> vbExclamation, "ConcatRelated()"
> Resume Exit_Handler
> End Function
>
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>

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