ASQL Reference

Added February 2026

The FETCHR_DYNFLDNUMX option on the SQLOP_FETCH_ROW operation offers a somewhat "smarter" variation (compared to FETCHR_DYNFLDNUM) on how the fields in a multi-level DYNSTRUCT are matched up to the fields in the result set. To clarify the difference, consider the following

defstruct ST_SUB

    map2 a,s,10

    map2 b,b,2

endstruct

 

defstruct ST_REC

    map2 f1,s,20

    map2 dummy

        map3 f2,b,4

        map3 f3,s,4

    map2 sub,ST_SUB

    map2 f4,f,6

endstruct

 

map1 rec, ST_REC

 

Assuming eight or more fields in the result set (result1 - result8), the two variations FETCHR_DYNFLDNUM and FETCHR_DYNFLDNUMX would assign the results to the DYNSTRUCT rec as follows:

In other words, the original FETCHR_DYNFLDNUM ignored the levels of the fields in the target structure, which probably doesn't make any sense, given that some of the fields overlay others. FETCHR_DYNFLDNUMX attempts to be smarter by ignoring header fields (e.g. rec.dummy) that have no explicit defined type, and conversely to ignore sub-fields within structures that do have an explicit type (e.g. rec.sub). The theory here is that the database would not have a dummy header field and would treat the struct ST_SUB as a single raw field.

If neither of these schemes works conveniently in your situation, the other option is match up the results to the DYNSTRUCT fields by name using FETCHR_DYNFLDNAME (or one of the non-DYNSTRUCT variations).

The DYNSTRUCT-related FETCHR_xxx symbols are defined in SQL.DEF as follows:

Note that this change does not affect or require updating the ASQL connectors (libashodbc and libashmysql).

History

2026 February, A-Shell 7.0.1783:  Add support for FETCHR_DYNFLDNUMX.