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 Entire forum ➜ MUSHclient ➜ Bug reports ➜ DatebaseStep bug?
DatebaseStep bug?

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Posted by Ron   China  (15 posts)  Bio
Date Reply #15 on Tue 15 Dec 2009 06:48 PM (UTC)
Message
Hi Nick,

Thanks for your reply.

The problem happened too when i used your Lua code.

I think the problem happened between two different local language system, I know this is very hard to reappear in your computer.

So ignore it please, I have found another way to solve this problem.

Thanks for your help.

Yours,
Ron
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Posted by Ddid   China  (19 posts)  Bio
Date Reply #16 on Sat 30 Oct 2010 10:02 PM (UTC)
Message
The same problem has been taken place in mine here.

Just want to know your solution.
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Posted by Ddid   China  (19 posts)  Bio
Date Reply #17 on Sat 30 Oct 2010 10:59 PM (UTC)
Message
I am not a C++ expert, but I think maybe following codes is the reason of causing this problem:

SetUpVariantString (vaResult, strResult);

in methods_database.cpp line 312

and


return strResult.AllocSysString();

in methods_database.cpp line 282
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Posted by Nick Gammon   Australia  (23,169 posts)  Bio   Forum Administrator
Date Reply #18 on Sat 30 Oct 2010 11:10 PM (UTC)
Message
Are you using Perl like the original poster?

Can you give me a snippet which reproduces the problem? On page one, I made a test which could not reproduce it.

I am assuming we are dealing in UTF-8, which should be handled OK by SetUpVariantString, however if you can give me some test data I can investigate further.
- Nick Gammon

www.gammon.com.au, www.mushclient.com
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Posted by Nick Gammon   Australia  (23,169 posts)  Bio   Forum Administrator
Date Reply #19 on Sat 30 Oct 2010 11:16 PM (UTC)
Message
This was my test (in Lua) modified to show the SQL length:


DatabaseOpen ("db", GetInfo (66) .. "utf8_test.db", 6)

DatabaseExec ("db", [[
DROP TABLE IF EXISTS test;
CREATE TABLE test(name TEXT NOT NULL);
]])
      
hello = utils.fromhex ("E5A4A7E5AEB6E5A5BD")  -- utf8: 大家好

print ("length before add=", #hello)

-- insert a record
DatabasePrepare ("db", "INSERT INTO test (name) VALUES ('" .. hello .. "')") 
DatabaseStep ("db") 
DatabaseFinalize ("db")  
      
-- prepare a query
DatabasePrepare ("db", "SELECT name, length(name) from test")

-- execute to get the first row
rc = DatabaseStep ("db")  -- read first row

-- now loop, displaying each row, and getting the next one
while rc == 100 do
  
  values = DatabaseColumnValues ("db")

  print ("length after add=", #values [1])
  print ("name=", utils.tohex (values [1]))
  print ("length from SQL=", values [2])

  rc = DatabaseStep ("db")  -- read next row

end -- while loop

-- finished with the statement
DatabaseFinalize ("db")


DatabaseClose ("db")  -- close it


Output was:


length before add= 9
length after add= 9
name= E5A4A7E5AEB6E5A5BD
length from SQL= 3


Note that the SQL length(name) function correctly reports 3 characters (that is, 3 Unicode characters) rather than 9 bytes.
- Nick Gammon

www.gammon.com.au, www.mushclient.com
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Posted by Ddid   China  (19 posts)  Bio
Date Reply #20 on Sat 30 Oct 2010 11:18 PM (UTC)
Message
I used the same lua testing code, but get different result:

length before add= 9
length after add= 8
name= E5A4A7E5AEB6E5A5


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Posted by Nick Gammon   Australia  (23,169 posts)  Bio   Forum Administrator
Date Reply #21 on Sat 30 Oct 2010 11:31 PM (UTC)
Message
Which version of MUSHclient?
- Nick Gammon

www.gammon.com.au, www.mushclient.com
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Posted by Ddid   China  (19 posts)  Bio
Date Reply #22 on Sat 30 Oct 2010 11:38 PM (UTC)
Message
Quote:

Welcome to MUSHclient version 4.61!
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Posted by Ddid   China  (19 posts)  Bio
Date Reply #23 on Sat 30 Oct 2010 11:40 PM (UTC)
Message
Nick Gammon said:

This was my test (in Lua) modified to show the SQL length:


DatabaseOpen ("db", GetInfo (66) .. "utf8_test.db", 6)

DatabaseExec ("db", [[
DROP TABLE IF EXISTS test;
CREATE TABLE test(name TEXT NOT NULL);
]])
      
hello = utils.fromhex ("E5A4A7E5AEB6E5A5BD")  -- utf8: 大家好

print ("length before add=", #hello)

-- insert a record
DatabasePrepare ("db", "INSERT INTO test (name) VALUES ('" .. hello .. "')") 
DatabaseStep ("db") 
DatabaseFinalize ("db")  
      
-- prepare a query
DatabasePrepare ("db", "SELECT name, length(name) from test")

-- execute to get the first row
rc = DatabaseStep ("db")  -- read first row

-- now loop, displaying each row, and getting the next one
while rc == 100 do
  
  values = DatabaseColumnValues ("db")

  print ("length after add=", #values [1])
  print ("name=", utils.tohex (values [1]))
  print ("length from SQL=", values [2])

  rc = DatabaseStep ("db")  -- read next row

end -- while loop

-- finished with the statement
DatabaseFinalize ("db")


DatabaseClose ("db")  -- close it


Output was:


length before add= 9
length after add= 9
name= E5A4A7E5AEB6E5A5BD
length from SQL= 3


Note that the SQL length(name) function correctly reports 3 characters (that is, 3 Unicode characters) rather than 9 bytes.


I have run above lua testing code, but got following result:

length before add= 9
length after add= 8
name= E5A4A7E5AEB6E5A5
length from SQL= 3


In fact, I think following code caused this problem:

strResult.AllocSysString();

But, C++, I just know a little bit.
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Posted by Nick Gammon   Australia  (23,169 posts)  Bio   Forum Administrator
Date Reply #24 on Sat 30 Oct 2010 11:47 PM (UTC)
Message
DatabaseColumnValues does not call AllocSysString.

DatabaseColumnValues is the call that gets back the data which you are receiving incorrectly.
- Nick Gammon

www.gammon.com.au, www.mushclient.com
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Posted by Nick Gammon   Australia  (23,169 posts)  Bio   Forum Administrator
Date Reply #25 on Sun 31 Oct 2010 12:17 AM (UTC)
Message
Can you install sqlite3.exe and then open your database, and type:


PRAGMA encoding;


And tell me what it says?
- Nick Gammon

www.gammon.com.au, www.mushclient.com
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Posted by Ddid   China  (19 posts)  Bio
Date Reply #26 on Sun 31 Oct 2010 12:29 AM (UTC)
Message
Quote:

CString is based on the TCHAR data type. If the symbol _UNICODE is defined for a build of your program, TCHAR is defined as type wchar_t, a 16-bit character encoding type; otherwise, it is defined as char, the normal 8-bit character encoding. Under Unicode, then, CStrings are composed of 16-bit characters. Without Unicode, they are composed of characters of type char.

Above message is copied from:
http://msdn.microsoft.com/en-us/library/ey142t48(v=VS.80).aspx

I think I'm wrong before.

But please check this problem again, above quote message is the reference that about this problem's causing(what I can find):


CString strResult;


Thanks.
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Posted by Nick Gammon   Australia  (23,169 posts)  Bio   Forum Administrator
Date Reply #27 on Sun 31 Oct 2010 12:36 AM (UTC)
Message
I have reproduced your problem by changing the "Language for non-Unicode programs" to "Chinese (PRC)".

So at least now I can work out what is causing it...

I think you are probably right, it is something to do with CString.
- Nick Gammon

www.gammon.com.au, www.mushclient.com
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Posted by Ddid   China  (19 posts)  Bio
Date Reply #28 on Sun 31 Oct 2010 12:39 AM (UTC)
Message
Nick Gammon said:

Can you install sqlite3.exe and then open your database, and type:


PRAGMA encoding;


And tell me what it says?



The result is:

UTF-8
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Posted by Ddid   China  (19 posts)  Bio
Date Reply #29 on Sun 31 Oct 2010 12:45 AM (UTC)
Message
Nick Gammon said:

I have reproduced your problem by changing the "Language for non-Unicode programs" to "Chinese (PRC)".

So at least now I can work out what is causing it...

I think you are probably right, it is something to do with CString.


Great!
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