Here's how I planned to implement bind variables for InterBase driver:
InterBase does not support bind variables alla Oracle. Instead
it allows SQL statements with positional parameters, like
SELECT col1, col2 FROM table1 WHERE col3 = ? AND col4 > ?
Positional parameters are denoted with question marks and they
have to be described using appropriate InterBase API calls after
the statement is prepared, but prior its actual execution. Once
prepared, statement can be reused (re-executed) using another
set of positional parameter values.
My idea is to write thin Tcl layer (ns_ib) which will transform
ACS-friendly constructs like:
SELECT col1, col2 FROM table1 WHERE col3 = :tclvar1 AND col4 > :tclvar2
into IB-friendly form shown above, grabbing $tclvar1 and $tclvar2 and
passing them to driver as textual representation of positional parameter
values. Fortunately, when filling positional parameters, InterBase can
convert textual representation into any IB native datatype, although
this conversion should not be too hard to write ourselves *if* we know
which datatype we should convert into.
I suspect that PostGres provides similar functionality.
