Tcl still only has one data type, which is the string. It has different internal representations to allow representing integers etc more efficiently, but since that is not part of the formal semantics of the language, those representations are not data types.
At the level of its C API-which is the level at which it integrates with sqlite-it indeed has multiple data types, it even has a structure to represent them, Tcl_ObjType: https://www.tcl-lang.org/man/tcl8.4/TclLib/ObjectType.htm