QmlDesigner: Improve sqlite id

https://www.sqlite.org/autoinc.html says that "If no negative ROWID
values are inserted explicitly, then automatically generated ROWID
values will always be greater than zero."

So zero is an invalid value.

This changes reflect on it and makes it an invalid value too. Null is a
special value in SQL and it could cast to zero by accident. To prevent
that ambiguty we make zero an invalid value too.
You can explicit add negative rowids but that has size overhead because
positive values can be compressed. So explicit not positive values are
not supported.

Change-Id: I417ea9fec1573cfd9f1a98134f8adc567021988c
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

1 files changed, 2 insertions, 2 deletions

diff --git a/src/libs/sqlite/sqliteids.h b/src/libs/sqlite/sqliteids.h
index a0562b4df4..7613a2df46 100644
--- a/src/libs/sqlite/sqliteids.h
+++ b/src/libs/sqlite/sqliteids.h
@@ -63,7 +63,7 @@ public:
 #pragma GCC diagnostic pop
 #endif
 
-    constexpr bool isValid() const { return id >= 0; }
+    constexpr bool isValid() const { return id > 0; }
 
     explicit operator bool() const { return isValid(); }
 
@@ -74,7 +74,7 @@ public:
     [[noreturn, deprecated]] InternalIntegerType operator&() const { throw std::exception{}; }
 
 private:
-    InternalIntegerType id = -1;
+    InternalIntegerType id = 0;
 };
 
 template<typename Container>