[Erw-devel] Adding abstract datatypes

[erw-devel]

Congrats on the htmlarea - thats a good functionality to add and it looks
good.

I'm curious - is there any intention to abstract out the SQL datatyps so
you can create your own domain based types and then map those to the
database you are using?

For example :

<enum id="invstat" type="int">
        Status values for invoices, indicating their current disposition.
        <enumval value="1"  label="Invoice Unsent"/>
        <enumval value="2"  label="Invoice Sent"/>
</enum>


Rather than type="int", lets say I want only 0 and positive numbers
(naturals). I use $TARGET to say 'the name of what i create goes here'.


types.xml:
<!DOCTYPE erl PUBLIC "-//DSI//DTD ERL V1.2//EN" "file://erl-types.dtd">
<type id="natural">
 <rdbms>
   <type>oracle</type>
   <version>8.1.6</version>
   <create>$TARGET integer check ($TARGET > 0)</create>
 </rdbms>
</type>


Obviously there are some tricks, since the above could also (to some
people preferably) be done as follows:

create table foo {
bar integer,
CONSTRAINT $TARGET_natural
          CHECK ($TARGET > 0)
);

so the syntax above would ideally support inline (first version) and
named/after table definition versions.


Is it possible? Hard? Likely? :)

Alfred Werner