World: r3wp
[SQLite] C library embeddable DB .
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BrianH 23-Nov-2007 [605] | SQLite used to only have text values - numbers were translated at runtime. Perhaps the REBOL driver hasn't caught up. |
Pekr 23-Nov-2007 [606x2] | I don't understand what is our /direct mode good for, it does things as {"1234"} .... without it, rebol stores "1234" .... now if you want use tools like sqliteadmin, you would be mad using /direct mode stored values ... |
I simply want rebol string "1234" to be stored as '1234' and when returned from query to be it once again "1234" not integer if I use '1234' (when using compose and sending string query) | |
BrianH 23-Nov-2007 [608x3] | MySQL has a non-standard command for inserting if not there for update: REPLACE. SQLite has more detailed conflict resolution, but includes REPLACE as a MySQL-compatible shortcut for INSERT OR REPLACE (the OR REPLACE is itself a shortcut for ON CONFLICT REPLACE). I agree that UPDATE should have the option of acting like INSERT OR REPLACE. |
As for the datatype mismatch, I would have to look at the code of sqlite.r to see if it is aware that SQLite data is no longer typeless. | |
Here is the SQLite docs about datatypes: http://www.sqlite.org/datatype3.html | |
Pekr 23-Nov-2007 [611] | It seems to me I will work with /direct refinement. That way REBOL string "aaaaa" is stored in sqlite as 'aaaa', so direct queries for 'aaaa' in console work, and back-loading (select) to rebol returns it as a rebol string. Without direct, 'aaaaa' would be returned as word ... |
Robert 23-Nov-2007 [612x3] | sql ["select * from test where id = ?" 5] |
The SQLite driver transforms all necessary " and ' stuff. | |
Never had a problem with this. | |
Pekr 23-Nov-2007 [615x5] | not without direct .... |
guys, have you ever got to situation, that working with rebol itself was more productive than with SQL? I redone my version of inventory checking to SQL, and thas thing imports for 10x more time, and most of the checks I do on rebol side anyway. Kudoz to remove-each function too :-) | |
how to do effectively following using SQL? | |
our subsidiary company changed IDs of some products during the inventory in our system ;-) I need to create table called e.g. transform-id(oldid, newid) .... and now I would like to somehow do: foreach row maintable [if found? in transform table maintable/id, then replace maintable/id with newid) :-) | |
I really sometimes think of simply submitting two queries into sql, having results in block, doing it in rebol level, and then to build tables from the scratch by inserting into new tables :-) | |
Maarten 23-Nov-2007 [620] | Yep. Rebol is superb for data manipulation |
Ashley 25-Nov-2007 [621] | Perhaps the REBOL driver hasn't caught up. ... SQLite datatypes have not changed for a long time, the driver supports them all in direct mode. I don't understand what is our /direct mode good for ... http://www.dobeash.com/SQLite/user-guide.html#section-2.1.3 |
BrianH 25-Nov-2007 [622] | OK, I think that is what Petr concluded :) |
Ashley 25-Nov-2007 [623] | even if column type is text ... see http://www.sqlite.org/datatype3.html#affinity |
Pekr 27-Nov-2007 [624x5] | WTF! I got burried by very strange behavior, which I would like to know what happened. IMO it is not related to SQLite itself, but maybe it is a deeper REBOL bug? Simply put I have following statement: sql "update or ignore produkty set kod = (select novy_kod from prevodnik_devitky where prevodnik_devitky.kod=produkty.kod) where exists (select kod from prevodnik_devitky where prevodnik_devitky.kod=produkty.kod)" ... and I was becoming crazy, that the update did not happen. No indexes used (well, I am starting practically with sql, so no need to mess things more :-), and when I put EXACTLY the same line into SQLiteAdmin tool, it was performed OK. I was really becoming mad, because it seemed to randomly work, when I changed/simplified the expression. Then I remembered my 2 years old ODBC scripts, when we imported data into SAP, from Database Advantage Server. I remembered there was some problem with multiline statement unless I used trim/lines. I thought to myself, well, it was ODBC driver related, but why not to try it? So I tried to reformat my query to: sql trim/lines "update or ignore produkty set kod = (select novy_kod from prevodnik_devitky where prevodnik_devitky.kod=produkty.kod) where exists (select kod from prevodnik_devitky where prevodnik_devitky.kod=produkty.kod)" ... and it started to work from my script. And I ask once again - What is going on here? 2 hours lost, which drove me nearly insane :-) I use no special editor but Notepad. The statement returned no error, so I thought it got performed, just incorrectly. It all seems to be related to one aspect - line is too long, so it wraps in Notepad and unless I use trim/lines, it is not performed. Any educated gues to what is happening here? It is not SQLite related imo, I just did not know where to put it, as general bugs group is not here .... |
ah, today I got another data corruption with sqlite driver .... | |
uh, it is update or replace which messes my data with nonsense :-( update or replace produkty set kod = (select novy_kod from prevodnik where prevodnik.kod=produkty.kod) where exists (select kod from prevodnik where prevodnik.kod=produkty.kod) It is supposed to simply to lookup the "prevodnik" (translator) table, if there is new code (novy_kod). both tables seem to be OK, but after that statement kod in produkty (products) gets messed up .... | |
produkty.kod is unique ... if I remove "or replace" part, data seem to be OK, but it just no more does what I need it to do .... | |
I found the culprit but I doubt it is enough to track possible bug. Issuing following statement will make subsequent update corrupting data: sql trim/lines "insert into prevodnik select kod, nazev, puvodni_kod, puvodni_kod, typ from produkty where substr(kod,1,1)='9' and kod like '%BZ'" update or replace produkty set kod = (select novy_kod from prevodnik where prevodnik.kod=produkty.kod) where exists (select kod from prevodnik where prevodnik.kod=produkty.kod) | |
Robert 29-Nov-2007 [629x2] | Petr, the new SQLite 3.5.3 release states: Fix a long-standing bug in INSERT INTO ... SELECT ... statements where the SELECT is compound. |
Maybe that's the problem? | |
Pekr 29-Nov-2007 [631x3] | gee, what are they doing? 50KB more size of dll to fix few bugs? They should aredy fix their docs whee they claim that other engine libraries start at 450KB ... they are nearly there too ... |
... and they definitely should completly remove their claim that 1 file for db is an advantage. That is the most serious obstacle of sqlite ... simplicity comes via ability to easily backup ... one file per index, table ... | |
Robert - tried that. Sadly it does not fix the issue. I will try to get to their ml and post the finding. Maybe I am doing something incorrectly, otoh I think that corruption should never happen, even if query would be nonsense :-) | |
Ingo 30-Nov-2007 [634] | Well, simplicity lies in the eyes of the beholder ... just having to back up a single file seems pretty easy to me ... |
Graham 30-Nov-2007 [635] | me too |
Pekr 1-Dec-2007 [636] | if that size is not necessarily 100MB and you don't need to back-up all the files all the time .... |
PeterWood 1-Dec-2007 [637x2] | ..then why don't you just back up the tables that you ? |
..want ???? | |
Pekr 2-Dec-2007 [639x2] | you can, by creating some code to do so, not by simply looking into the directory and using default OS facilities. |
well, SQLite is really cool, but simply noone can defend that one argument to me. I also communicated that "defficiency" on their ml, and simply put - it is the way it is. 'Attach function is just nasty workaround, nothing more. But - I talk about some 5% of feature, which would I found usefull, I will use sqlite anyway, as simply put there is no simple replacement to what it provides ... | |
PeterWood 2-Dec-2007 [641] | I didn't think that you needed to write any code to backup individual tables in SQLite but just supply the table name as a parameter to the .dump command. I believe you can do this from the command line with SQLite3. |
Pekr 12-Dec-2007 [642] | It seems I found a bug :-) http://www.sqlite.org/cvstrac/tktview?tn=2832 |
GiuseppeC 13-Dec-2007 [643] | I ask here too, I want to adopt a database system for my rebol projects: which are the advantages of SQLLite over RebDB ? Why should adopt the first or the latter ? |
Henrik 13-Dec-2007 [644] | I ask here too No need to cross post. We can all see the messages. |
Pekr 13-Dec-2007 [645x2] | SQLite has one main advantage - it supports SQL like syntax - you can join tables. I can't imagine living without those features anymore. |
RebDB is also mostly - in memory only database. It does not live on hd. So - SQLite has one advantage here - it supports locking over file-shared SQLite database. | |
GiuseppeC 13-Dec-2007 [647] | Sorry Henrik my intentions where not to SPAM, I have later found the SQL lite group than the RebDB. Promise I'll write only once starting from now. Don't be upset :-) |
Pekr 13-Dec-2007 [648] | That is still not full-fledget SQL server - those provide you with network independent access ... |
GiuseppeC 13-Dec-2007 [649] | Pekr, joining tables and having the data on disk are already two good points for SQL Lite. Obviusly I need Rebol/Pro licence before using it. |
Pekr 13-Dec-2007 [650] | not necessarily. |
GiuseppeC 13-Dec-2007 [651] | I ahve read in the doc that Rebol/Pro is necessary. Could you explain ? |
Pekr 13-Dec-2007 [652x2] | Well - there is btn-sqlite (better than nothing) driver on rebol.org It works, with one bad effect - black console window appearing during the shell call. Just recently I put it on high priority list for W.7.6 to be fixed - all is needed is to set one flag for shell call .... |
I hope that it gets fixed. | |
GiuseppeC 13-Dec-2007 [654] | Thanks pekr, I'll take a look at it. Next year, when I'll have more knoledge in RebGUI and Rebol2 I need to start a project which needs a database but it will be a single user project so SQL lite.is good enough. |
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