Hello
I'd like to use a timestamp column in each table to keep track of when a
column was last updated, so that a user can be notified of a problem when
trying to updated a record that has already been updated by another user
while the first user was still working on the original data.
In www.sqlite.org/lang_conflict.html, I read about the "UPDATE OR ROLLBACK"
instructions, so tried the following using Todd Tanner's VBified SQLite
DLL... but am not notified of anything special: SQLite doesn't return any
error, and just reports that no row matches:
=========== CODE ===============
Private Declare Sub sqlite3_open Lib "SQLite3VB.dll" (ByVal FileName As
String, ByRef handle As Long)
Private Declare Function sqlite_get_table Lib "SQLite3VB.dll" (ByVal
DB_Handle As Long, ByVal SQLString As String, ByRef ErrStr As String) As
Variant()
Private Declare Function number_of_rows_from_last_call Lib "SQLite3VB.dll"
() As Long
'row already updated by someone else, so timestamp=2 -> no row
actually matches constraint
mQuery = "begin;"
mQuery = mQuery & "update OR ROLLBACK mytable set name='bart',
timestamp=2 where id=1 and timestamp=1;"
mQuery = mQuery & "commit"
sqlite3_open DBFile, DB
If DB > 0 Then
mVar = sqlite_get_table(DB, QueryStr, mErrStr)
If mErrStr <> "" Then
ErrStr = mErrStr
sqlite3_close DB
Exit Function
Else
'No error + empty array! How to be notified of conflict?
=========== CODE ===============
Thank you
G.
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