Re: New RDBMS implementation

On Mon, 03 May 2004 17:56:04 -0300,
=?iso-8859-1?q?Leandro_Guimar=E3es_Faria_Corsetti_Dutra?= <leandro_at_dutra.fastmail.fm> wrote:

It seems a private mail, my apologies if I bore the rest of the group.

>Em Mon, 03 May 2004 20:31:21 +0000, Alfredo Novoa escreveu:
>
>>> Details?
>>
>> Well, it is a very modest project. The progress is slow but IMO it is
>> promising. It is a full time project since the last week :)
>
> Academic assignment, unemployment or A Very Nice Employer(R)?

Rather nice associates, but they don't have any interest in creating a DBMS, they only want to use it.

>> It is not a direct competitor because it is a complete DBMS that does not
>> need an SQL DBMS behind the scenes.
>
> Neither will Dataphor some time hence...

I have to work in something meanwhile :)

And it is probable that they can not implement the Transrelational Model.

>OTOH it is a complete
>RAD environment.

The frontend is not flexible enough for us and I have not found documentation about the Data Access Components.

 And we need very flexible physical database design, many summarized snapshots, cheap server licenses and preferabily a distributed DBMS architecture with many data cached in the desktop PCs, compressed and encrypted communications, etc.

>> And the core is 'inspired' in the Transrelational Model.
>
> Did you actually read the patents?

Of course, but my data structures are rather different and they can be used in disk based DBMSs. Date mentioned that the Transrelational Model was adapted to be used with disk based DBMSs and I wonder if they used the same solution as me (modified B-Trees).

I also wonder if the modifications are enough to avoid problems with the patent if I want to distribute it in the US, Canada or Japan.

Software patents are crazy.

>> I am implementing it on the .Net framework.
>
> Are you keeping an eye in Portable.Net or Mono portability?

No, I am keeping an eye in the Compact .Net framework. But I don't think I am using anything non portable.

>>> Are you sticking to either D4 or Tutorial D?
>>
>> The language is almost identical to Tutorial D.
>
> Where and why did you feel you had to differ from what's
>published, for curiosity's sake?

The published LARL grammar has many mistakes, it is a toy language and some constructions are ugly IMO.

I added all the constructions scattered by the book and the "intro" book like foreign keys, outer joins, authorities, etc. But I have not added yet the temporal extensions.

It is possible to write a join b join c instead of (a join b) join c. (This is not possible with the published grammar).

All this statements are valid and in my version:

var r real relation { a integer } key { a }; var r relation { a integer } key { a };
var r relation { a# integer } key { a# }; var r real relation { a integer }; // key { a } is assumed.

var v virtual relation r where ...
var v view r where ...

r asc a; // returns an array

start transaction and commit transaction are not required. Any language script is executed in the same transaction by default.

The language is case insensitive and it does not have '_' characters inside the keywords. Like in SameTypeAs();

The THE_ operators don't have the THE_ prefix.

It is possible to assign an expression to another expression:

a join b := c minus d;

It is possible to reference an expression in a foreign key definition

var a relation { a integer }

    foreign key {a} references a join b;

It has more builtin types like: numeric, date, timestamp, int32, int64, int8, etc.

IF is optional in END IF. And the same for while, case, etc.

TABLE_DEE and TABLE_DUM are called Dee and Dum because they are not tables.

The untypable operators like set inclusion are written as english keywords.

And other little changes.

BTW what do you think about Tutorial D as a general purpose programming language?

I am also toying with standalone Tutorial D applications.

For instance the hello world app is:

application HelloWorld
  call WriteLine( System.Console, 'Hello World' ); end application;

2048 bytes.

'.' and '#' are valid chars in identifiers in my version.

Another version:

application HelloWorld
  prefix System.
    call WriteLine(Console, 'Hello World' );   end prefix
end application;

This would piss off any OO zealot :)

The most important problem is the IDE :(

> I remember Nathan Allan asking you to collaborate rather than
>competing,

He told me he will write me a lot of months ago, but it seems that he reconsireded that.

I knew almost nothing about the .Net framework in that moment, but now I think that .Net is the best option. The imperative parts of Tutorial D are very easy to implement with the .Net framework.

I made a prototype for Win32 using Firebird as the backend but I dropped it because it was slow and some features were very hard to implement and because I have learned about the Transrelational Model.

> I found it confusing because his is not free software to
>enable collaboration in the first place.

He told me something about the implementation of a backend for Dataphor but I don't have information enough and I didn't know almost anything about the .Net Framework.

>But I hoped you were going
>D4 so that we'd have two competing, compatible products.

It would be rather easy to make a D4 parser. Parsers and lexers are very easy.

BTW I heared that programming languages have copyright in the US :(

> BTW, what about planned licensing, availability etc?

A bit soon for that, but my associates would kill me if I publish all the code :)

But it is a little crazy project. I can't promise anything. I will do only all I am able to do, but I am optimist and it is a very interesting job.

Saudaçoes
  Alfredo

alfredonovoa_at_ncs.es (remove lfredo to respond) Received on Tue May 04 2004 - 03:54:40 CEST