Sharan Rao said the following, On 2007-12-01 21:17:
I was facing problems with the function Connection::querySingleString() in
Sybase, as the " LIMIT " clause is not supported.
Sharan, thanks for your time; here's the patch you can apply for LIMIT 1
ussue. I am looking forward your opinion on it.
BTW, I propose to use [email protected] mailing list now. Who knows, maybe there's
someone interested in tracking the development of the Sybase/MSSQL driver and
can provide valuable feedback. (already CC'd).
Information for others: Sharan uses the db-lib from the FreeTDS project:
http://www.freetds.org/
--
regards / pozdrawiam, Jaroslaw Staniek
Sponsored by OpenOffice Polska (http://www.openoffice.com.pl/en) to work on
Kexi & KOffice: http://www.kexi.pl/en, http://www.koffice.org
KDE3 & KDE4 Libraries for MS Windows: http://kdelibs.com, http://www.kde.org
Index: kexidb/connection.cpp
===================================================================
--- kexidb/connection.cpp (revision 744501)
+++ kexidb/connection.cpp (working copy)
@@ -2460,7 +2460,7 @@
Q_ASSERT(sql || query);
//! @todo does not work with non-SQL data sources
if (sql)
- m_sql = addLimitTo1 ? (*sql + " LIMIT 1") : *sql; // is this
safe?
+ m_sql = m_driver->addLimitTo1(*sql, addLimitTo1);
KexiDB::Cursor *cursor;
if (!(cursor = sql ? executeQuery( m_sql ) : executeQuery( *query ))) {
KexiDBWarn << "Connection::querySingleRecord(): !executeQuery()
" << m_sql << endl;
@@ -2501,7 +2501,7 @@
tristate Connection::querySingleString(const QString& sql, QString &value,
uint column, bool addLimitTo1)
{
KexiDB::Cursor *cursor;
- m_sql = addLimitTo1 ? (sql + " LIMIT 1") : sql; // is this safe?;
+ m_sql = m_driver->addLimitTo1(sql, addLimitTo1);
if (!(cursor = executeQuery( m_sql ))) {
KexiDBWarn << "Connection::querySingleRecord(): !executeQuery()
" << m_sql << endl;
return false;
@@ -2569,13 +2569,13 @@
if (m_driver->beh->SELECT_1_SUBQUERY_SUPPORTED) {
//this is at least for sqlite
if (addLimitTo1 && sql.left(6).toUpper() == "SELECT")
- m_sql = QString("SELECT 1 FROM (") + sql + ") LIMIT 1";
// is this safe?;
+ m_sql =
m_driver->addLimitTo1(QString::fromLatin1("SELECT 1 FROM (") + sql + ")",
addLimitTo1);
else
m_sql = sql;
}
else {
if (addLimitTo1 && sql.left(6).toUpper() == "SELECT")
- m_sql = sql + " LIMIT 1"; //not always safe!
+ m_sql = m_driver->addLimitTo1(sql, addLimitTo1);
else
m_sql = sql;
}
Index: kexidb/driver.h
===================================================================
--- kexidb/driver.h (revision 744501)
+++ kexidb/driver.h (working copy)
@@ -351,6 +351,13 @@
\a keywords should be 0-terminated array of
null-terminated strings. */
void initDriverSpecificKeywords(const char** keywords);
+ /* \return SQL statement @a sql modified by adding limiting
command,
+ (if possible and if @add is true). Used for optimization for
the server side.
+ Can be reimplemented for other drivers. */
+ inline virtual QString addLimitTo1(const QString& sql, bool
add) {
+ return add ? (sql + QString::fromLatin1(" LIMIT 1")) :
sql;
+ }
+
friend class Connection;
friend class Cursor;
friend class DriverManagerInternal;
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