Andl syntax has been evolving over time. The original syntax was somewhat cryptic and a bit of a challenge for anyone to understand. Also some parts of the syntax could be ambiguous in some situations, or at least would limit the generality of some constructs. It has also become increasingly clear that much of the syntax has direct parallels in SQL, and that it is people who already know SQL who are most likely to be interested.
Introducing Syntax 6. The key development is that each of the parts of a query takes a form that is closely parallel to a corresponding construct in SQL. So, for example:
- The function
.where(expression)performs the same function as an SQL WHERE clause. - The function
.order(field, field...)performs the same function as an SQL ORDER BY clause. - The function
.set{ field, field:=value }performs the same function as an SQL SELECT.
And there are lots more. These are postfix functions (with a dot) that follow a relational expression. On the other hand JOIN and UNION are infix operations, placed between two values. When you put them together you get something like this SQL query and the corresponding Andl code.
// SQL>select distinct sname from s, sp, p where p.color='Red' and s.s#=sp.s# and p.p#=sp.p#
(S .set{ S#, SNAME } join SP .set{ S#, P#} join P .set{ P#,COLOR }) .where(COLOR='Red') .set{ SNAME }
The order is not quite the same but all the same elements are there. If you know SQL, now with Syntax 6 you can learn Andl easily!
Latest releases are on the Downloads page. There are lots more examples of SQL and matching Andl syntax in the sample file SPPSample1.andl.