Support Informix nested Structs

[lukaseder]

System information:

• Operating system (distribution) and version: Microsoft Windows [Version 10.0.22000.556]
• DBeaver version: Version 21.3.2.202112271055
• Java version: openjdk version "17" 2021-09-14 (build 17+35-2724)

Connection specification:

• Database name and version: IBM Informix Dynamic Server Version 14.10.FC5DE
• Driver name: com.informix.jdbc.IfxDriver
• Do you use tunnels or proxies (SSH, SOCKS, etc)? No

Describe the problem you're observing:

When projecting nested rows and nested collections of rows, the result is just a IfxStruct.toString() rendition which describes the data structure's metadata, not the data contents

Steps to reproduce, if exist:

select 
  row(1, 2) as a, 
  row(1, row(1, 2)) as b, 
  multiset { 1, 2 } as c,
  multiset { row(1, 2) } as d;

The output is:

As you can see:

• a is split up correctly into its components
• b doesn't correctly show the nested row
• c seems to format some reasonable output (not sure if by accident)
• d doesn't show anything useful

The problem is that as soon as java.sql.Struct types are nested, the formatting stops working

PostgreSQL doesn't have this problem, because PostgreSQL produces a string representation of the data structure, which is reasonable enough as a result:

select 
  row(1, 2) as a, 
  row(1, row(1, 2)) as b, 
  array [ 1, 2 ] as c,
  array [ row(1, 2) ] as d;

Resulting in

I still like it better when Dbeaver creates separate columns for nested data structures, but if that's too complex, then some reasonable string representation of a Struct would do as well.

[LonwoLonwo]

Thanks for the idea and for the investigation @lukaseder