On 18-2-2012 22:38, Dmitry Yemanov wrote: > 15.02.2012 20:01, Mark Rotteveel wrote: > >> Does SQL_VARYING require the sqllen to be updated as well, or can that >> be left as it was originally set by isc_dsql_describe_bind? > > I'd say it should correspond to the real data. You're not required to > use isc_dsql_describe_bind(), after all.
The 'problem' is that using (and reusing) prepared statements is very common in Java, and the bind information provided by isc_dsql_describe_bind() is used inside Jaybird as well. Changing the sqllen for SQL_VARYING to the actual length, will change the information available to the driver about the field (in the current implementation of Jaybird that is). For example: if I have VARCHAR(10) field, then Jaybird 'knows' based on the sqllen that upto 10 characters will fit, if I would set a two character string and change the sqllen to 2, then on the next use Jaybird would (incorrectly) think that the field is upto 2 characters and will throw a string truncation error if a a 3+ character string would be set. The reason that Jaybird will throw that string truncation error if the value is longer then the (described) sqllen is that it saves a roundtrip to the server to get that same error; Firebird will throw that error if the parameter exceeds the field length (see CORE-251 / CORE-3559). I could change Jaybird to keep a copy of the original bind description and use that, but that would be more complex then only changing the SQL_VARYING sqldata to contain the payload length + actual data without padding (the current implementation pads upto sqllen). So if I could keep the sqllen untouched that would save me some work :) -- Mark Rotteveel ------------------------------------------------------------------------------ Virtualization & Cloud Management Using Capacity Planning Cloud computing makes use of virtualization - but cloud computing also focuses on allowing computing to be delivered as a service. http://www.accelacomm.com/jaw/sfnl/114/51521223/ Firebird-Devel mailing list, web interface at https://lists.sourceforge.net/lists/listinfo/firebird-devel
