Обсуждение: open and closed paths ...

I am using PostgreSQL 7.0.3. I have tried the isopen() function but it
doesn't seem to work (or it is not fully implemented yet).
In my opinion the third record is a closed path but the isopen()
functions return f.
Have I done something wrong, have I got something wrong or is it a bug?
   Hans



shop=# SELECT * FROM temppath;     fieldname
----------------------((1,3),(4,12))((3,1),(2,8),(10,4))((3,1),(2,8),(3,1))((1,1),(2,2),(3,3))
(4 rows)

shop=# INSERT INTO temppath(fieldname) VALUES ('(1,1), (2,3)');
INSERT 51857 1
shop=# SELECT isopen(fieldname) FROM temppath;isopen
--------fffff
(5 rows)

Hans-Jürgen Schönig writes:

> I am using PostgreSQL 7.0.3. I have tried the isopen() function but it
> doesn't seem to work (or it is not fully implemented yet).
> In my opinion the third record is a closed path but the isopen()
> functions return f.

For no good reason apart from ancient tradition, paths enclosed in
parentheses, like ((3,1),(2,8),(10,4)), are implicitly closed.  To make an
open path brackets should be used, like [(3,1),(2,8),(10,4)].

-- 
Peter Eisentraut      peter_e@gmx.net       http://yi.org/peter-e/

The only problem left is the correct syntax of the command when using [].
I've tried some versions but it did not work.
Maybe Tom can include an example into the docs.
   Hans


shop=# INSERT INTO temppath(fieldname) VALUES '((1,3), (4,12))';
ERROR:  parser: parse error at or near "'"
shop=# INSERT INTO temppath(fieldname) VALUES ((1,3), (4,12));
ERROR:  parser: parse error at or near ","
shop=# INSERT INTO temppath(fieldname) VALUES ('(1,3), (4,12)');
INSERT 51947 1
shop=# INSERT INTO temppath(fieldname) VALUES ['(1,3), (4,12)'];
ERROR:  parser: parse error at or near "["
shop=# INSERT INTO temppath(fieldname) VALUES '[(1,3), (4,12)]';
ERROR:  parser: parse error at or near "'"
shop=# INSERT INTO temppath(fieldname) VALUES '[(1,3), (4,12)]'::path;
ERROR:  parser: parse error at or near "'"
shop=# INSERT INTO temppath(fieldname) VALUES ['(1,3), (4,12)']::path;
ERROR:  parser: parse error at or near "["

shop=# SELECT isopen(fieldname) FROM temppath;isopen
--------f
(1 row)

Hans-Jürgen Schönig writes:

> The only problem left is the correct syntax of the command when using [].
> I've tried some versions but it did not work.
> Maybe Tom can include an example into the docs.
>
>     Hans
>
>
> shop=# INSERT INTO temppath(fieldname) VALUES '((1,3), (4,12))';
> ERROR:  parser: parse error at or near "'"

Should be VALUES ('((1,3), (4,12))');  The outer parentheses belong to the
INSERT command, the quotes delimit the data literal, whatever is inside
the quotes is the data type's business.

> shop=# INSERT INTO temppath(fieldname) VALUES ((1,3), (4,12));
> ERROR:  parser: parse error at or near ","
> shop=# INSERT INTO temppath(fieldname) VALUES ('(1,3), (4,12)');
> INSERT 51947 1
> shop=# INSERT INTO temppath(fieldname) VALUES ['(1,3), (4,12)'];
> ERROR:  parser: parse error at or near "["
> shop=# INSERT INTO temppath(fieldname) VALUES '[(1,3), (4,12)]';
> ERROR:  parser: parse error at or near "'"
> shop=# INSERT INTO temppath(fieldname) VALUES '[(1,3), (4,12)]'::path;
> ERROR:  parser: parse error at or near "'"
> shop=# INSERT INTO temppath(fieldname) VALUES ['(1,3), (4,12)']::path;
> ERROR:  parser: parse error at or near "["

-- 
Peter Eisentraut      peter_e@gmx.net       http://yi.org/peter-e/