Preparing 12.10 BSON columns with DATE fields for upgrade

Before you upgrade from Informix® 12.10 you must unload binary JSON (BSON) columns with DATE fields into JSON format so that you can load them into Informix 15.0.0

1. Create an external table with a similar name as the original table and with JSON (instead of BSON) format for the date.
   For example, assume that the original table named datetab has a BSON column named i that has DATE fields in it. Use the following statement to create an empty, external table named ext_datetab that has a JSON column with DATE fields. The DATAFILES clause specifies the location and name of the delimited data file, which in this example is disk:/tmp/dat.unl.

   create external table ext_datetab (j int, i json) using
           (datafiles ("disk:/tmp/dat.unl"),
           format "delimited");

2. Unload the data from the original table into the external table.
   For example:

   insert into ext_datetab select j, i::json from datetab;