From b8f140b70ebe617a807f7a104f15563c8ef51d2d Mon Sep 17 00:00:00 2001 From: Christian Ehrlicher Date: Mon, 6 Mar 2023 20:44:48 +0100 Subject: [PATCH] SQL/ODBC: add another check to detect unicode availability in driver Since ODBC does not have a direct way finding out if unicode is supported by the underlying driver the ODBC plugin does some checks. As a last resort a sql statement is executed which returns a string. But even this may fail because the select statement has no FROM part which is rejected by at least Oracle does not allow. Therefore add another query which is correct for Oracle & DB2 as a workaround. The question why the first three statements to check for unicode availability fail is still open but can't be checked since I've no access to an oracle database. Fixes: QTBUG-96616 Fixes: QTBUG-102958 Change-Id: I8ec0115bbfbfc40852bcfb8e94b4b4ad3e395b37 Reviewed-by: Volker Hilsheimer (cherry picked from commit f19320748d282b1e68fc2e3de2b0cf9ec44b49ef) Reviewed-by: Qt Cherry-pick Bot --- src/plugins/sqldrivers/odbc/qsql_odbc.cpp | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/src/plugins/sqldrivers/odbc/qsql_odbc.cpp b/src/plugins/sqldrivers/odbc/qsql_odbc.cpp index 9c4d61eb4bf..9ba829e8269 100644 --- a/src/plugins/sqldrivers/odbc/qsql_odbc.cpp +++ b/src/plugins/sqldrivers/odbc/qsql_odbc.cpp @@ -2129,7 +2129,18 @@ void QODBCDriverPrivate::checkUnicode() hDbc, &hStmt); - r = SQLExecDirect(hStmt, toSQLTCHAR("select 'test'"_L1).data(), SQL_NTS); + // for databases which do not return something useful in SQLGetInfo and are picky about a + // 'SELECT' statement without 'FROM' but support VALUE(foo) statement like e.g. DB2 or Oracle + const auto statements = { + "select 'test'"_L1, + "values('test')"_L1, + "select 'test' from dual"_L1, + }; + for (const auto &statement : statements) { + r = SQLExecDirect(hStmt, toSQLTCHAR(statement).data(), SQL_NTS); + if (r == SQL_SUCCESS) + break; + } if (r == SQL_SUCCESS) { r = SQLFetch(hStmt); if (r == SQL_SUCCESS) {