On 3/8/06, cstrader <[EMAIL PROTECTED]> wrote:
> Would someone be willing to share with me c++ code that reads the result of a
> select query into an array representing the data of the j rows in a selected
> column? I understand that callback() is executed once for each row of the
> data. But what is the best and fastest way to iteratively write these row
> data into a single array that I can pass to my host program?
Callbacks are problematic in C++. It's tricky to get the address of a
class member
and provide the 'this' pointer correctly. Here's a quick example of
reading a single
record (I have a wrapper around the sqlite calls, but I think it gets
the message across):
// open database
dbOpen();
// check to see if user is admin or moderator
string sql = "SELECT
CookieUser,CookieVisit,Timezone,CookieLife,CGI,URL,ContactName,ContactMail,Description
FROM Setup";
// prepare statement instead of building it to avoid sql injection attacks
if ( ! dbPrep( sql ) )
throw ConException( string("Cannot prepare sql: ") + sql +
string(", ") + + sqlite3_errmsg(db) );
switch ( dbStep() )
{
case SQLITE_ROW:
// get results ( 0 based index!!! )
CookieUser = dbColumn( 0 );
CookieVisit = dbColumn( 1 );
Timezone = dbColumn( 2 );
CookieLife = atol( dbColumn( 3 ) );
CGI = dbColumn( 4 );
URL = dbColumn( 5 );
ContactName = dbColumn( 6 );
ContactMail = dbColumn( 7 );
Description = dbColumn( 8 );
break;
case SQLITE_DONE:
if ( CookieUser.empty() )
throw ConException( string("Invalid configuration") );
break;
default:
throw ConException( string("Cannot execute sql: ") + sql );
break;
}
// clean up when finished
dbFinalize();
dbClose();
dbColumn looks like this:
//---------------------------------------------------------------------------
// return a pointer to the text of a result row
// 0 based index!
//---------------------------------------------------------------------------
char* Convention::dbColumn( const unsigned int Index )
{
char* p = (char*) sqlite3_column_text( pStmt, Index );
return (char*) ( p ? p : "" );
}
