The Rel Forum

I've made a note in the TODO list to provide THE_INTEGER(INTEGER) RETURNS INTEGER.

A further thing to note: If you implement a type like POSINT that is inherited from a built-in type, a backup generated of its database will have all literals where the type constraint is true changed to that type! For example, the following definition: TYPE POSINT IS { INTEGER CONSTRAINT INTEGER > ...

I vaguely recall that there is some mention somewhere that the non-empty <derived possrep def list> requirement does not apply to subtypes of built-in types, with the result that I made the following legitimate: TYPE POSINT IS { INTEGER CONSTRAINT INTEGER > 0 }; A bit of a caveat, though: Subtyping ...

Sorry, at present you can't, because the built-in aggregate operator SUM is only defined over INTEGER and RATIONAL.

A future update will support user-defined aggregate operators, which will permit defining SUM over user-defined types.

Try SUM(PARTS, THE_WEIGHT(WEIGHT))

That seems reasonable and I'll consider it.

Toward that end, I generally make constraint names long and descriptive.

Is Berkeley Java DB still being used in any way? Yes, every relvar that isn't bound to some external data source has its data stored using the Berkeley Java DB. Every relvar, whether it's bound to some external data source or not, has its metadata stored using the Berkeley Java DB. NatTable is mere...

Will applications written in Rel version 1.0.12 run unchanged in version 1.0.13? Yes, they should. Will we have a place to input commands along with being able to clear, load, save etc like there is now? Yes. The command line is still available as before. Will output from operators be seen on an ou...

The notice is only ever supposed to occur once a script has finished running, so I'm not sure why it's appearing in the middle of a FOR loop (unless you're using EXECUTE?) but I can imagine circumstances where it would be undesirable. I'll provide an option to turn it off. I've added this to my &quo...

NatTable is a grid widget that integrates with the SWT widgets (see https://en.wikipedia.org/wiki/Standard_Widget_Toolkit) that I've used to build the new Rel user interface (which was formerly known as DBrowser.) NatTable is simply used to display and edit relvars. Doing data entry and updates via ...

A relvar defined as a connection to a table in an external DBMS can (in principle) allow tuples to be inserted. So, defining a relvar on a table in an external DBMS is a way to export data to that DBMS. The forthcoming Rel update has an all-new user interface, which includes the ability to view and ...

I'm not clear what "storing a Rel relvar in another dbms" means. A Rel relvar can represent data in a native Rel database, or it can represent data in an external data source (like a table in a PostgreSQL or SQLite database, for example), but it can only be accessed in a Rel database. Do y...

The forthcoming update now implements a TYPE_OF(e) operator that returns a TypeInfo value about any expression e , where a TypeInfo is a supertype of either a Scalar or NonScalar type. The sys.Catalog relvar now has an Attribute attribute that returns a NonScalar value. The types are defined as foll...

It's fixed in 1.0.13, which is getting closer to release.

It's a quirk of the Rel parser that it treats an integer preceded with a zero (0) as being an octal number. So, if you type, say, 01232534 into DBrowser it works fine, but if you type 01232539 it fails because '9' isn't an octal digit. It's on my TODO list to sort this out at some point, but it's no...