World: r3wp

it's like you have your own computer that you can reinstall stuff 
or OS .. separated from others but it's running on virtualisation 
software so there are many such separate computers per one real computer 
, so it's *cheaper* than paying for having a full server

ah, virtual machine, ok ...

you can put cheyenne there or any other custom server you want

yes

hm.. I have a question for SQL / sqlite experts : 

I have a query with two JOINS . There is parent table which has 2 
subtables ... in each subtable I need to aggregate (SUM) some value 
... 


select i.*, SUM(ib.price * ib.qty) as amount, SUM(ip.amount) as payed_amount
	from invoice_sent as i 

  left outer join invoice_sent_b as ib on i.id = ib.id_invoice_sent

  left outer join invoice_sent_p as ip on i.id = ip.id_invoice_sent
	group by i.id order by i.title;


The problem is tha because of join , the amount is correct , is the 
sum of values in invoice_sent_b , but payed_amount is multiplied 
by the number of rows invoice_sent_b has . 


I understand why this happens, but I don't know how to prevent it, 
if I want to get all data in one query.


( I know how to solve the prolem , but it's outside the DB so it's 
more of  a hack  -- I also ger COUNT of _b table rows and divide 
second SUM by it on client )

ah, my method with count won't work because count also multiplies 
if I have more than 1 columnt in second subtable

This guy has totally the same problem but no answer http://forums.devshed.com/db2-development-114/left-outer-join-3-tables-sum-field-of-2nd-3rdt-588801.html

found solution. I need to join with subqueries:

				{SELECT * FROM } table { as i 
					LEFT OUTER JOIN
					( 

      SELECT id_} table { as ibs_paren, SUM(price * qty) as amount 
							FROM } table {_b ib
							GROUP BY id_} table {
					) ibs ON i.id = ibs_paren
					LEFT OUTER JOIN
					(

      SELECT id_} table { as ips_paren, SUM(ip.amount) as payed_amount 
							FROM } table {_p ip
							GROUP BY ip.id_} table {
					) ips ON i.id = ips_paren
				order by title;

Has anyone done any benchmarks for running scripts from a DB instead 
of from the filesystem?

Say, where there are a moderate number of moderate sized scripts 
- could it be quicker just to fire up an SQLite connection and access 
the scripts/modules from records as opposed to flat file?

Perhaps particularly a CGI environment where each instance is a separate 
process?

If you had persistent connection and if sqlite does some caching 
it could be faster, but if you need to open a connection on each 
request I think it would be much slower because that is more expensive 
(I assume).. it probably also matters how many scripts do you need 
to run per request

The OS caches things too, don't forget.

It shouldn't be hard to devise a small benchmark though.

.

I seem to get an error with sqlite after using "call" to start an 
external program.

** User Error: SQLite out of memory
** Near: make error! reform ["SQLite" error]

Anyone experience this?

Check if you have the right path to file.. and make it an absolute 
path.. and if you have the right version .. sqlite != sqlite3

It works fine until I try to call another app. Paths do not change 
but I'm not using absolute paths. I'll need to test that...

I got similar error but I don't know if it was for the relative path 
or not the right version of dll / so

I changed all the paths to absolute paths...it seems to have done 
the trick. Thanks for the hint, Janko!

youre welcome

I apologize if this is a repeat of an earlier message - I thought 
I submitted, but never saw it appear.


Question: With REBOL/View 2.7.6 under Windows XP, using SQLite driver 
v1.0.6, should I be able to use the concatenate operator (||) in 
a SELECT statement?  Query works under the sqlite3 command line, 
and a similar SELECT without the concatenate returns values as expected:

>> sql "select jobid, role from roles where userid = 'cda6'"
== [[1124 prgr] [1125 test]]

>> sql "select jobid || role from roles where userid = 'cda6'"
** Syntax Error: Invalid integer -- 1124prgr
** Near: (line 1) 1124prgr
>>

Reversing the column order in my concatenate makes it work, but not 
what I want:

>> sql "select role || jobid from roles where userid = 'cda6'"
== [[prgr1124] [test1125]]
>>

Try this >>sql "select '' || jobid || role from roles where userid 
= 'cda6'"

I think the problem is the first column is a integer, so SQLite driver 
think the result is a integer ( invalid integer ), with '' the first 
column is a string

Thanks for the suggestion Manu.  Sounded good to me, but I get the 
same error even with the empty string at the front:


>> sql "select '' || jobid || role from roles where userid = 'cda6'"
** Syntax Error: Invalid integer -- 1124prgr
** Near: (line 1) 1124prgr
>>


even though it appears to be integer, jobid variable is text, according 
to SQLite:
>> sql "select typeof(jobid) from roles"
== [[text] [text] [text] [text]]
>>
Again, thanks!  I welcome any other suggestions.

Why not make the JOIN on the Rebol side?

Jack, finally I saw the problem


The return of sql isn't two blocks of string, it's two blocks of 
word. So 1124prgr isn,t a valid word and isn't a valid integer

>> a: sql "select jobid, role from roles where userid = 'cda6'"
>> type? first first a
==word


You need to add the /direct refinement to sql and it returns strings

>> sql/direct "select jobid || role from roles where userid = 'cda6'" 
==[["1124prgr"]["1125 test"]]

Robert - thanks...that's what I eventually did.


Manu - thank you for making clear what the /direct refinement does...I 
had read about that in the SQLite Driver Guide, didn't understand 
it since REBOL is still new to me, and forgot about it.  Works perfectly! 
 So much to learn....

Is there a problem with:

http://www.dobeash.com/

seems like domain is up for sale ??

Probably hasn't paid renewal fees!

It is back online again.

Does REBOL SQLite support SQLLite3 ?

yes, it does ...

Is it possible to use the sqlite driver for a file that resides on 
the internet?

As long as you can access it via a normal file-path, yes. Can be 
slow but should work.

stupid me, I only now realized sqlite driver supports prepared statements 
too and I was concatenating strings all along.

I seem to recall a note about locking issues over a network path, 
so ymmv.

Does following mean, we could have trouble to propelry sort (using 
collations) because of UTF-8?


http://stackoverflow.com/questions/181037/case-insensitive-utf-8-string-collation-for-sqlite-c-c

The sorting problem with collations applies to Unicode, not just 
UTF-whatever, so it is a problem. Mostly a problem of size: The actual 
colation sorting code is small, but the collation data is large. 
Add more than one or two and REBOL gets huge.

A solution would be to move the sorting out into the host code, where 
it can be made to use any system-specific sorting code, which should 
work for platforms with good Unicode support like Windows, OS X and 
some Linux distros. The problem with that is that the data would 
probably need to be migrated to the host format before the host routines 
could be used; string! is not UTF-8 or UTF-16 internally, it is UCS-8 
(in theory), UCS-16 or UCS-32 (in theory), all fixed-length encodings. 
That would add a lot of overhead to sorting.

ICU seems to have such library with nice license... Unfortunately 
the Binary-only package for one platform is like 10Megabytes..
http://icu-project.org/download/4.2.html#ICU4C

This unifoce srting seems to be a mess.. Well, technically they do 
have some standards, but trying to even think any decent size implementation 
of that.. 
http://www.unicode.org/reports/tr10/

Is there a method to "dump" the contents of a sqlite db for back-up 
purposes using the the driver?

why not just copy the file?

Robert, Well, that's what I do do now but I was wondering if there 
was also a command.

James, if you have the sqlite command available, you can do:

sqlite /path/to/file.db .dump >/path/to/dumpfile.sql

Thanks Gabriele. I was looking for a programatic way but I think 
I'll stick to just copying the file.

well, that is programmatic. .dump is a command for the sqlite utility. 
if you want to do it from REBOL, you have to code it yourself, as 
it's not a SQL command.

Is this an accepted method of populating the fields of a view form 
or is there a more precise method?

btn-next: func[][
   if (counter  < (length? db)) [
    counter: counter + 1
    lname/text: db/:counter/2
    fname/text: db/:counter/3
    spouse/text: db/:counter/4
    email/text: db/:counter/5
    hphone/text: db/:counter/6
    cphone/text: db/:counter/7
    addr/text: db/:counter/8
    city/text: db/:counter/9
    state/text: db/:counter/10
    zip/text: db/:counter/11
    
    show window
    ]
]