Re: [sqlite] sqlite3_column_text() returning partial results
There it is, when I printed this value out to a txt file everything was there.
Apparently there is some sort of character limit when displaying strings in
debug mode in Visual Studio 2010, news to me...
Thanks everyone!
-Original Message-
From: sqlite-users-boun...@sqlite.org [mailto:sqlite-users-boun...@sqlite.org]
On Behalf Of Pavel Ivanov
Sent: Wednesday, December 21, 2011 2:33 PM
To: General Discussion of SQLite Database
Subject: Re: [sqlite] sqlite3_column_text() returning partial results
Now, this is a very good test case and explanation what happens, except...
How did you check value of CString testing after iterating though the entire
char array? Did you look at it in your debugger? Maybe your debugger is not
capable of showing CString contents longer than 2048 symbols? The value of
string testing you gave with Windows-style line ends gives me 2040 bytes,
indentation of the next line is 8 bytes, so if total limit is 2048 bytes then
you won't see any contents of the next line...
Can you output contents of CString testing using printf() and see if it shows
the same 2040 bytes?
Pavel
On Wed, Dec 21, 2011 at 1:34 PM, Jacob A. Camp wrote:
> So delving further into this has gotten me nothing else; this is the best I
> could do to simplify this to understandable steps.
>
> (I'm new to this service so no idea if attachments are allows so sorry
> about the length in advance)
>
> I have this code:
>
> sqlite3_stmt* state = NULL;
> CString sql = _T("SELECT RelationshipHierarchyXML FROM
> TlAssembly WHERE id=?");
> //Query the database
> RawSQLTlID (sql, id, &state);
> bytes = sqlite3_column_bytes(state, 0); //This line
> returns 8955
> //Try getting data as blob
> const void * temp = sqlite3_column_blob(state, 0);
> //Set the size for simplification
> char chararray[9000];
> //Copy value into the char array
> memcpy( chararray , temp , bytes);
> CString testing;
> //Iterate through all elements
> for (int x = 0; x < 8999; x++)
> {
> int temp = chararray[x];
> char temp2 = chararray[x];
>
> //if the char is null or not supportted don't append it
> to CString
> if (temp < 1 || temp > 255)
> {
> //This gets hit a few times with negative int values
> temp = temp;
> }
> else
> {
> //Append the char to the XML string
> testing.AppendChar(temp2);
> }
> }
>
> return success;
>
> At this point the CString testing contains on a portion of the characters of
> the XML field which makes it unusable.
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Re: [sqlite] sqlite3_column_text() returning partial results
4 FLAT ENDMILL I 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 true I 1 0 0 0 0 1 0 0 0 0 1 0 0 2.5 0 1 Target DefaultTarget I 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 true I 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 LinearAxis I 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 true I 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 Real Holder I 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 true I 1 0 0 0 0 1 0 0 0 0 1 0 0 6.12099987 0 1 Target DefaultTarget I 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 #6699cc 1 Holder 0 d22d6e4c-be03-471e-bcac-0e5d12852fb2 0 1 0 0 2.5 0.75 1.3118700546473194 Y #6699cc 1 Tool 1.3118700546473194 ---- false VerticalLathe ", -Original Message- From: sqlite-users-boun...@sqlite.org [mailto:sqlite-users-boun...@sqlite.org] On Behalf Of Pavel Ivanov Sent: Wednesday, December 21, 2011 11:20 AM To: General Discussion of SQLite Database Subject: Re: [sqlite] sqlite3_column_text() returning partial results On Wed, Dec 21, 2011 at 10:41 AM, Jacob A. Camp wrote: > I have a line of code that executes that line: > > const unsigned char * temp2 = sqlite3_column_text(state, 0); > > This queries the database and after the call is complete I pass this value to > another function. This function then fails because temp2 points to a location > that contains the incomplete text. I then can view this text using my > debugger and I can see that the value has been clipped and the XML is invalid. Let me ask Igor's questions once again. How does your function understand that text is incomplete? Your debugger can show you incomplete string because temp2 is not a zero-terminated string, it can contain zeros in the middle. > Trying to access memory locations outside whatever is allocated by the return > of sqlite3_column_text sounds like it would result in undefined behavior? How do you know how much memory sqlite3_column_text allocated for the return? > sqlite3_column_bytes returns 8960 if that's helpful. Hint: the abov
Re: [sqlite] sqlite3_column_text() returning partial results
I have a line of code that executes that line: const unsigned char * temp2 = sqlite3_column_text(state, 0); This queries the database and after the call is complete I pass this value to another function. This function then fails because temp2 points to a location that contains the incomplete text. I then can view this text using my debugger and I can see that the value has been clipped and the XML is invalid. Trying to access memory locations outside whatever is allocated by the return of sqlite3_column_text sounds like it would result in undefined behavior? sqlite3_column_bytes returns 8960 if that's helpful. -Original Message- From: sqlite-users-boun...@sqlite.org [mailto:sqlite-users-boun...@sqlite.org] On Behalf Of Igor Tandetnik Sent: Wednesday, December 21, 2011 10:29 AM To: sqlite-users@sqlite.org Subject: Re: [sqlite] sqlite3_column_text() returning partial results Jake wrote: > For the previous post asking what occurs after 2030, there's nothing What do you mean, nothing? What exactly happens when you try to access p[2030]? > because the > returned value is only allocated for those characters. What makes you believe this? -- Igor Tandetnik ___ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users ** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept by MIMEsweeper for the presence of computer viruses. www.mastercam.com ** ___ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
[sqlite] sqlite3_column_text() returning partial results
Hello,
I've been looking into an issue that a few of our programmers have looked at as
well and it left us all wondering. Basically, our database has a VARCHAR column
that has an XML file written to it when the object is manipulated. I can use a
tool to view the database file and I can ensure that the entire field is filled
out correctly and the XML is correctly formed.
The field in the database contains 8955 characters and when I execute the
sqlite3_column_text() on that specific column to access the data, the const
unsigned char* that's returned only contains 2030 characters and the XML file
that I'm trying to reconstruct from it then becomes unusable. I even attempted
digging into the SQLite class and it seems that this value is obtained from the
official function calls.
In sqlite3.c:
static Mem *columnMem(sqlite3_stmt *pStmt, int i){
Vdbe *pVm;
int vals;
Mem *pOut;
pVm = (Vdbe *)pStmt;
if( pVm && pVm->pResultSet!=0 && inResColumn && i>=0 ){
sqlite3_mutex_enter(pVm->db->mutex);
vals = sqlite3_data_count(pStmt);
pOut = &pVm->pResultSet[i];
After the last line has been executed pOut contains members z and zMalloc which
both contain the same memory location that points to the char* that contains
the first 2030 characters and none of the rest that are stored in the VARCHAR
field.
Is there some limit to the amount of data that can be returned by this
function? I read over most of the documentation and didn't see it mentioning
any sort of restriction.
Thanks in advance,
--Jake
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