Question

If “read only” is checked in the Windows desktop properties for a .dbf or .mdb file,
and a Delphi 6 ADO connection (say, via Jet for an .mdb file or ODBC for a .dbf file)
is then used to open that database, TADOTable.CanModify returns true and
TADOTable.ReadOnly returns false, apparently failing to detect the file is
actually read-only.

From the VCL source, it looks like .CanModify is just set from Supports(xUpdates)
and .ReadOnly is set from the LockType (even “read-only data source” in
TADOConnection.Properties returns 0), so those properties seem more like
tools for detecting connectionstring options as opposed to detecting the
database’s original read-only state.

So what’s the proper ADO technique to detect a database is marked read-only
before TADOTable.Edit is attempted? Seems the solution should not be
specific to Windows files, but some kind of database-independent technique
using just ADO. What’s the solution?

Answer 1

It’s a pity, but you can’t.

However, since the filename is part of the connection string, you can check yourself.