External Data Sources: materialized views not supported?

Materialized views don’t show up as external data sources. They are not supported, are they?

What do you mean by materialised views ? Do you mean remote SQL Views in a relational database, as this possible as Virtuoso presents tables, views and stored procedures to be attached to the Virtuoso server from External Data Sources. Although tables are presented by default as that is what most want to do, but there are check box options to list views and stored procedures for attachment.

I have a materialized view in a relational database. This view doesn’t show up in the list of the linkable external resources.
Check boxes are all checked

I setup simple test case in my local PostgreSQL 10 docker image with a SQL view:

De-iMac-2448:~ hwilliams$ iodbctest "DSN=pgr7la;UID=postgres;PWD=xxxxxx"
iODBC Demonstration program
This program shows an interactive SQL processor
Driver Manager: 03.52.0815.0106
Driver: 07.00.190410 OpenLink PostgreSQL Lite Driver (pgr7_mt_lt.so)

SQL>create table hugh(c1 integer);
Statement executed. 0 rows affected.

SQL>insert into hugh values (1);
Statement executed. 0 rows affected.

SQL>create view hughw as select * from hugh;
Statement executed. 0 rows affected.

SQL>select * from hughw

c1         
-----------
1  
        
 result set 1 returned 1 rows.
SQL>

and can see the SQL View in the Virtuoso Conductor External Data Source UI for attachment, which can be done and the view queried from Virtuoso …

In your example you created a “simple” view. This does work also for me.
In PostgreSQL I have also materialized views [1]: those don’t show up in the UI.

[1] https://www.postgresql.org/docs/10/rules-materializedviews.html

I see what you mean, I have not come across materialized views in PostgreSQL before, checking with the development if support for materialised views can be added to our PostgreSQL ODBC Driver …