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leegold

Help With SQLite_Backup

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leegold

Hi,

I to access a DB every few seconds so I thought to take the file DB "mirror"/copy it to a memory DB and check the memory DB every few seconds. sqlitebackup.au3 seems an easy way to do this - to make the memory copy. But I must be missing something when I try a simple test because I didn't get anything from a select statement on the memory DB. But when I substitute the disk DB with the same code it works. I tried:

...

...

#include <SQLite.au3>
#include <SQLite.dll.au3>
#include <sqlitebackup.au3>

$sSQliteDll = _SQLite_Startup()
$sDbName = "C:\sqlite\relays.db"
$hDskDb = _SQLite_Open($sDbName)
Local $aRow

Local $hmemDb = _SQLite_Backup($hDskDb, ':memory:', Default, Default, Default, Default, Default)

Local $d = _SQLite_Exec($hmemDb, "Select * From sched", "_cb")    ; this does not work
; Local $d = _SQLite_Exec($hDskDb, "Select * From sched", "_cb")  ; this works

Func _cb($aRow)
    For $s In $aRow
        ConsoleWrite($s & @TAB)
    Next
    ConsoleWrite(@CRLF)
EndFunc   ;==>_cb
; ...
; ...
_SQLite_Close()
_SQLite_Shutdown()

I guess my questions is - What am I doing wrong? Thanks.

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kylomas

leegold,

Are you sure it is even running.  When I run it (under SCiTE) I get

! Au3check doesn't support input files encoded as UTF8 with BOM:

followed by

"C:UsersADMIN010Desktopsqlite backup.au3"(11,96) : error: _SQLite_Backup(): undefined function.

 

The version of _SQLite_Backup that I am using is dated 2010-03-08 (author - jchd)

Also,

I don't see anything in the UDF that suggests that ':memory:' is valid as the 2ND parm (destination database filename). 

Once you get the script to run you can add error checking after the function call.  I do not know what the UTF8/BOM message means. 

kylomas

edit: running 3.3.10

Edited by kylomas

Forum Rules         Procedure for posting code

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jchd

kylomas,

":memory:" indeed is a valid pseudo-filename for a memory-based DB, as mentionned in _SQLite_Open help.

Those whishing to use Au3Check may rewrite the include as ASCII (Au3Check doesn't support UTF-8).

leegold,

I strongly doubt that your _SQLite_Exec on the disk-based DB would work: read help file again and you'll see that _SQLite_Exec doesn't produce any output. Use _SQLite_GetTable2D instead.


This wonderful site allows debugging and testing regular expressions (many flavors available). An absolute must have in your bookmarks.
Another excellent RegExp tutorial. Don't forget downloading your copy of up-to-date pcretest.exe and pcregrep.exe here
RegExp tutorial: enough to get started
PCRE v8.33 regexp documentation latest available release and currently implemented in AutoIt beta.

SQLitespeed is another feature-rich premier SQLite manager (includes import/export). Well worth a try.
SQLite Expert (freeware Personal Edition or payware Pro version) is a very useful SQLite database manager.
An excellent eBook covering almost every aspect of SQLite3: a must-read for anyone doing serious work.
SQL tutorial (covers "generic" SQL, but most of it applies to SQLite as well)
A work-in-progress SQLite3 tutorial. Don't miss other LxyzTHW pages!
SQLite official website with full documentation (may be newer than the SQLite library that comes standard with AutoIt)

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leegold
snip...

 

leegold,

I strongly doubt that your _SQLite_Exec on the disk-based DB would work: read help file again and you'll see that _SQLite_Exec doesn't produce any output. Use _SQLite_GetTable2D instead.

 

Hi,

Did you mean to say the _SQLite_Exec will not work on the memory DB? Because it does work OK with the disk DB:)  You mean it won't work witht memory DB(?), and it certainly seems not too...so I should try _SQLite_GetTable2D for the memory DB instead was  what you were saying(?) I don't want to put works in you mouth but _SQLite_Exec works on the disk DB fine. Or did I not understand?

You mentioned a help file above. if you could cite a link I'd be grateful. Thank you jchd!

 

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leegold

I tried this which works fine when using a disk DB but will not work on the memory DB I tried to mirror from the disk db.

I get Sqlite error 21: Library Used Incorrectly. 

I just want to run SQL on the memory DB - is my memory DB valid that I'm trying to make? I must not be seeing this in the documentation - I will try to read more...thanks

#include <SQLite.au3>
#include <SQLite.dll.au3>
#include <File.au3>
#include <sqlitebackup.au3>

Local $aResult, $iRows, $iColumns, $iRval

$sSQliteDll = _SQLite_Startup()
$sDbName = "C:\sqlite\relays.db"
$hDskDb = _SQLite_Open($sDbName) ; Open a permanent disk database

Local $hmemDb = _SQLite_Backup($hDskDb, ':memory:', Default, Default, Default, Default, Default)

$iRval = _SQLite_GetTable2d($hmemDb, "SELECT * FROM sched;", $aResult, $iRows, $iColumns)
If $iRval = $SQLITE_OK Then
    _SQLite_Display2DResult($aResult)
Else
    MsgBox($MB_SYSTEMMODAL, "SQLite Error: " & $iRval, _SQLite_ErrMsg())
EndIf

_SQLite_Close()
_SQLite_Shutdown()




_SQLite_Close()
_SQLite_Shutdown()

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leegold

I'm just going to read the disk db into an array and use that - much simpler. I would still like to know like to know what I was doing wrong and I'm grateful for the help provided.

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jchd

Instead try this:

#include <MsgBoxConstants.au3>

#include <SQLite.au3>
#include <SQLite.dll.au3>
#include <File.au3>
#include "sqlitebackup.au3"

Local $aResult, $iRows, $iColumns, $iRval

$sSQliteDll = _SQLite_Startup()
$sDbName = "relaystest.db"
$hDskDb = _SQLite_Open($sDbName) ; Open a permanent disk database

_SQLite_Exec($hDskDb, "create table if not exists test (colA text);")
_SQLite_Exec($hDskDb, "insert into test values ('at least one row here');")

Local $hmemDb = _SQLite_Backup($hDskDb, ':memory:')


$iRval = _SQLite_GetTable2d($hmemDb, "SELECT * FROM test;", $aResult, $iRows, $iColumns)
If $iRval = $SQLITE_OK Then
    _SQLite_Display2DResult($aResult)
Else
    MsgBox($MB_SYSTEMMODAL, "SQLite Error: " & $iRval, _SQLite_ErrMsg())
EndIf

_SQLite_Close()
_SQLite_Shutdown()

BTW and once again, _SQLite_Exec on any DB can't return any (SQL) result, just a error code.


This wonderful site allows debugging and testing regular expressions (many flavors available). An absolute must have in your bookmarks.
Another excellent RegExp tutorial. Don't forget downloading your copy of up-to-date pcretest.exe and pcregrep.exe here
RegExp tutorial: enough to get started
PCRE v8.33 regexp documentation latest available release and currently implemented in AutoIt beta.

SQLitespeed is another feature-rich premier SQLite manager (includes import/export). Well worth a try.
SQLite Expert (freeware Personal Edition or payware Pro version) is a very useful SQLite database manager.
An excellent eBook covering almost every aspect of SQLite3: a must-read for anyone doing serious work.
SQL tutorial (covers "generic" SQL, but most of it applies to SQLite as well)
A work-in-progress SQLite3 tutorial. Don't miss other LxyzTHW pages!
SQLite official website with full documentation (may be newer than the SQLite library that comes standard with AutoIt)

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