For the record: it's not the Abstract-ness that leads to the index being ignored, it's the fact that the index is not defined in the primary superclass of Test.NewClass1. From secondary superclasses, only parameters, properties and methods are inherited, but not indices. So you can keep Test.NewClass Abstract, but make it inherit from %Persistent itself and then have Test.NewClass1 point to it as its primary superclass. I'll ask the doc team to make this a little clearer, as it's not obvious from this section of the doc nor the one on indices right now.

This said, @Robert Cemper 's suggested use of NoExtent is likely what you wanted to achieve.

Yes, it always behaved like this. Currently, table stats are stored as part of the class definition, based on the idea that they are often kind of static and belong with the application. That holds for certain types of applications, but in many cases it is a little too static and this is especially true for the Message Bank example here, as TuneTable cannot update class definitions for a read-only system class.

We have a project coming up to move the table stats to live with the data rather than keep them in the class definition and hope to bring that to an IRIS release in the course of 2023. In the meantime, the workaround suggested above, marking ENSLIB as writable, running TT and then marking it read-only again is reasonable (though quite a step from an official recommendation). Note that after upgrades, your ENSLIB will be overwritten and your stats will have been lost.

FYI, the last part of this article also touches on this subject

@Vitaliy Serdtsev is right in pointing to the resultset's metadata. That's where IRIS SQL registers column datatypes and he already pointed out that this is obviously not impacted by the presence of an ORDER BY. 

The resultset object returns the SQL-side value to ObjectScript, but on that ObjectScript side, the datatype no longer matters as it isn't strongly typed and still 1="1". Therefore, I don't think this constitutes an error.

FWIW, the reason you're seeing this is that due to the ORDER BY clause we're picking up that id value from the index' subscript rather than from the master map.

Unfortunately we're not able to offer transactions across linked tables. For one thing, the remote database may use different transaction semantics. I will request this gets clarified in our documentation, as it's not called out right now as a limitation of linked tables.

Where Oracle uses the FROM DUAL pseudo-table, IRIS will just do without a FROM clause altogether for cases where you just want to select a single row of constant expressions. The following statement should work:

INSERT INTO mytable (column1, column2, column_n)
  SELECT expr1, expr2, expr_n UNION ALL
   SELECT expr1, expr2, expr_n;

Oliver already pointed you at the key setting for this, but I thought I'd include a snippet from and link to the corresponding doc as well

If Source has a foreign key public RowID, and you want Destination to have the same foreign key relationship, you must define Destination with the ALLOWIDENTITYINSERT=1 parameter. When defining Destination as a persistent class, specify Parameter ALLOWIDENTITYINSERT=1;. When using CREATE TABLE to define Destination, specify %CLASSPARAMETER ALLOWIDENTITYINSERT=1. If a table is defined as ALLOWIDENTITYINSERT=1, this setting cannot be changed by the SetOption("IdentityInsert") method.

That would be through calling %Next() right away. The way how our query code works is to walk through results and tell you when it runs out of rows to pass back. 

Our online documentation has a feedback button that makes your comments immediately find their way to the doc writers. They really appreciate suggestions and usually turn them around quite quickly :-)

This is expected behaviour. for a SELECT statement, %Execute() (or %ExecDirect()) will set %SQLCODE to 0 if the statement was successfully executed and ready to return rows, or an error code if the execution went wrong. It's through the use of %Next() that it will figure out whether there are any rows left. The first %Next() call on such a resultset will return 0 and at the same time set %SQLCODE to 100. This behaviour is similar and perhaps even more visible in the case of %ROWCOUNT for SELECT statements, which increases with every call to %Next(). See also the docs for %Next() (second bullet)

The simple reason for this is that we're not building the whole result set upfront, but rather "get ready" to iterate through it with %Next() calls, as users may only be interested in the first few rows. Some call this a lazy execution model, but I prefer the term efficient :-). Of course, for DML statements such as UPDATE and DELETE, the %ROWCOUNT is known immediately upon execution, as there is no result set to scan through

Sorry to hear you ran into this. The issue was also detected during recent internal testing and we're in the process of fixing it. 

A little more documentation on the SQL projection of collection properties here.

Currently the SQLPROJECTION = table option is only available for "array of" properties. In 2022.1 we intend to make this option also available for "list of" properties.

If you're interested, I can dig up a script I wrote a while ago to create a class that projects a read-only view of your "list of" property. No warranty!