[GRASSLIST:7295] db.* commands

[Aldo Clerici]

Dear GRASSusers and developers,
I'm having some trouble with db.* commands and expecially with db.execute,
surely due to my poor knowledge of SQL language.
In the manual is written that db.execute executes any SQL statement, but in
the "GRASS SQL Interface" manual page
(..../grass-6.1.cvs/docs/html/sql.html) is specified that only a limited set
of SQL functions and operators are supported.
If this is correct I think it would be very useful to specify these
limitations in the db.execute manual page.
Furthermore it seems to me that there are other limitations regarding the
variable types. In fact in the suggested "SQL Guide and reference"
(www.redhat.com/docs/manuals/database/RHHDB-2.1-Manual/sql/sqlreference.html
) a long list of data types is reported, but actually only some of them are
accepted by db.execute (I tried successfully int, double, varchar(n)).
In conclusion the question is: is there a manual (or tutorial) where the
functions, operators and data types accepted by db.execute are reported?

A second point is that I cannot realize why the command:
echo "SELECT * FROM <vectormap>" | db.select
works correctly, while:
echo "SELECT * FROM <vectormap>" | db.execute
doesn't.

Many thanks in advance for any kind of answer.

Aldo Clerici
Parma University