On 1999-11-22, Zeugswetter Andreas SEV mentioned:
> > testdb=> \set singlestep on
> > testdb=> \set sql_interpol '#'
> > testdb=> \set foo 'pg_class'
> > testdb=> select * from #foo#;
>
> This is great, but may I object to the syntax ?
> The standard sql way to use host variables seems to be:
> select * from :foo where id = :id
>
> There will always be the problem with conflicting operators,
> and this one syntax, already needed by ecpg, it is hard enough.
I just pulled that syntax out of my hat, since it was the most
non-interfering way to go for now, but thanks for the tip, I'll be on the
task in a second. Of course, since the SQL standard is such a widely
available document, I should have found that myself ;)
Is there also a rule on what those variables can contain? I mean currently
they act like C macros, they can contain unbalances quotes, incomplete
backslash commands, everything. Or should they be restricted to SQL?
Also, looking for possible conflicts here, it seems that there is an
operator ':' for exponentiation, which is of course extremely mnemonic.
This reminds me of the ';' operator for logarithms, which I also use all
the time in mathematical writing. Are those operators actually standard or
just somebody's personal idea?
For example, what does this mean:
play=> select value, :value from test;value | ?column?
-------+---------------------- 5 | 148.413159102577 6 | 403.428793492735 99 | 9.88903031934695e+42
(3 rows)
Similarly for the ';' operator, where there are obvious problems.
Rationale anybody? Are they from PostQUEL times?
Um, okay, this goes even further. There seem to be functions called log
and dlog1 as well as exp and dexp with essentially the same functionality;
the one with the 'd' goes with float8 arguments, the other one with
numeric. Is this making sense to anybody?
-Peter
--
Peter Eisentraut Sernanders väg 10:115
peter_e@gmx.net 75262 Uppsala
http://yi.org/peter-e/ Sweden