Don't forget to cc: the list.
Dmitry Turin wrote:
Good day, Richard.
http://sql4.by.ru/site/sql40/en/author/wave_eng.htm
RH> example 2
RH> 1. I can see how one flight might follow another, but not contained. Do you
RH> not need some new object "flight_chain" or similar?
No !
Fork is possible, several flights might follow another,
thus several flights should be inside another.
1. One flight is not "contained" within another though. I board one
plane, fly, get off, board another, fly, ... - they are sequential not
contained. If you're trying to represent multiple options you should
really have something like:
<flight_chain ...>
<flight_options>
<flight...>
<flight...> These three flights represent options
<flight...>
</flight_options>
</flight_chain>
How do I get such a structure from a TML query?
2. If you nest flights then you'll be forced to repeat data, surely?
Multiple routes could end up mentioning flight id=123 several times and
each time have to repeat all possible options from it.
RH> 2. Alternatively, the <city> needs to indicate to which it's
RH> referring either as <startcity>/<endcity> or <city fromto="start"> or
RH> similar.
What is 'either as <startcity>/<endcity> or <city fromto="start">' ?
Looking at the resultset, how do I know whether a mentioned city is:
1. the start point of a flight
2. the end point of a flight
RH> 3. How am I constructing these queries?
There are five documents on
http://sql4.by.ru/site/sql40/en/author/index_eng.htm
RH> The whole point was so I didn't have to learn SQL, yes?
Nearly: sorting by first section of tree
(maybe by second section and so on after that)
is not seggested now
(user can sort, for examle, in browser by XSL).
Hang on, XSL is *not* easier to understand than SQL.
RH> syntax for these queries isn't obvious enough to me
What is not-obvious -
tree notation or work with fields inside section (record) in tree ?
If all of them, what is more not-obvious ?
The syntax of your queries is not obvious. I haven't read your guide,
but you did say that the whole point was *not* to have to learn
languages. If I'm going to learn only one query language, it'll be SQL
because everything uses it.
RH> 4. what use it is to have XML without a schema.
What is 'XML without a schema' ?
XML is not stored thing, it is a transport form for scheme.
Umm - xml schemas, that describe valid data for an xml document.
http://www.w3.org/XML/Schema
http://www.xml.com/pub/a/2001/12/12/schemacompare.html
RH> How does this TML setup avoid me having to write any php/perl/etc?
Any inquired tree
An "inquired tree" how? I'm sat here at my laptop, and I want to get a
list of flights into a spreadsheet I'm doing for my boss.
1. How do I create my TML query (assuming I haven't read the TML manual,
because if I can read manuals then SQL is viable)?
2. How do I get my query from my laptop to my database server?
3. How do I get results into the spreadsheet?
> (in reduction case - inquired one table or one view),
which is finished by '>>' at the end,
is in output automatically (port #80, HTTP protocol,
http://sql4.by.ru/site/sql40/en/author/inout_eng.htm
and
http://sql4.by.ru/site/sql40/en/author/introduction_eng.htm#http).
You trimmed the first part of my question: "Let's say I want to build a
holiday website. How does this TML setup avoid me having to write any
php/perl/etc?"
I'm a small travel agent, and I want to let customers see what flights I
can offer them. We're going to need a form that lets people choose from
a list of start and end cities, pick a date and see a list of flights
(sorted by cost, or length or some such). At present I'll build that
with e.g. PHP + SQL => PostgreSQL. What part of the process does TML
make easier?
--
Richard Huxton
Archonet Ltd
---------------------------(end of broadcast)---------------------------
TIP 4: Have you searched our list archives?
http://archives.postgresql.org
