Tim wrote:
Could you send me a doc patch based on my emails in that thread?
Tim.
First draft derived mainly from the ParamValues pod
(see embedded [NOTES TO TIM]):
=item C<ParamTypes> (hash ref, read-only)
Returns a reference to a hash containing the type information
currently bound to placeholders. The keys of the hash are the
'names' of the placeholders: either integers starting at 1, or,
for drivers that support named placeholders, the actual parameter
name string. The hash values are hashrefs of type information in
the same form as that provided to the various bind_param() methods
(See L</"Data Types for Placeholders"> for the format and values),
plus anything else that was passed as the third argument to bind_param().
Note that type information that is not relevant to a given
TYPE may be omitted, e.g., SCALE for SQL_CHAR.
[ NOTE TO TIM: Your note in the roadmap shows both the scalar and
hashref form of type info...in the interest of simplicity, I'd prefer
a single form (hashrefs); do you have a strong opinion one way
or the other ? ]
Returns undef if not supported by the driver.
[ NOTE TO TIM: Do you envision adding this info to the
ShowErrorStatement output ?]
See L</ShowErrorStatement> for an example of how this is used.
If the driver supports C<ParamTypes>, but no values have been bound
yet, then the driver should return a hash with the placeholder name
keys, but all the values undef; however, some drivers may return
a ref to an empty hash, or, alternately, may provide full type
information (e.g., if the prepare()'d SQL statement provides placeholder
type information).
It is possible that the values in the hash returned by C<ParamTypes>
are not I<exactly> the same as those passed to bind_param() or execute().
The driver may have modified the type information in some way based
on the bound values, other hints provided by the prepare()'d
SQL statement, or alternate type mappings required by the driver or target
database system.
It is also possible that the keys in the hash returned by C<ParamTypes>
are not exactly the same as those implied by the prepared statement.
For example, DBD::Oracle translates 'C<?>' placeholders into 'C<:pN>'
where N is a sequence number starting at 1.
The C<ParamTypes> attribute was added in DBI X.XX. Implementation
is the responsibility of individual drivers; the DBI layer default
implementation simply returns undef.
