[sqlite] error with authorizer, onecolumn and TCL
The following sequence gives an incorrect result value:
(ramsan) package require sqlite3
3.6.22
(ramsan) 2 % sqlite3 db :memory:
(ramsan) 3 % db authorizer myauth
(ramsan) 4 % proc myauth { cmd args } {
return SQLITE_OK
}
(ramsan) 6 % db eval { create table t(a,b) }
(ramsan) 7 % db onecolumn { select a from t }
SQLITE_OK
The error is probably due to the fact that the onecolumn TCL code,
in some cases (if there are no results), does not store a void string
as result. Then, a previous not valid TCL result (SQLITE_OK) is
returned as result of the onecolumn method.
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Re: [sqlite] what extension do you recommend
You should consider the extension for, at least, three situations: - Anti virus can check files differently depending on the extension - Backup programs can also react on this - Windows takes it into account when indexing files Compass Ing. y Sistemas Dr. Ramon Ribo http://www.compassis.com[EMAIL PROTECTED] c/ Tuset, 8 7-2 tel. +34 93 218 19 89 08006 Barcelona, Spain fax. +34 93 396 97 46 Daniel Önnerby escribió: Well... From the lack of responses I gather that you actually don't give a damn what file extension I use :) I think this is fare enough and maybe a SQLite database shouldn't be tied to a single file extension. Anyway.. Thanks for listening and thanks for the best database ever! Daniel Önnerby wrote: Hi all! I have developed a small windows application that use a SQLite database as it's main format. The file is NOT a kind of document, it's more of a settings-file stored in the users Application data-directory and the extension will not be associated with the application. I know I can use any kind of extension on this file, but what file-extension is the most common for SQLite-files, .db, .db3, .SQLite? What file-extensions do the SQLite management tools associate? What do you recommend? Best regards! Daniel - To unsubscribe, send email to [EMAIL PROTECTED] - - To unsubscribe, send email to [EMAIL PROTECTED] - - To unsubscribe, send email to [EMAIL PROTECTED] -
Re: [sqlite] Re: SQLite and nested transactions
Dennis,
I cannot agree here. Just imagine that the user decision is based on the
imported data.
Of course, you can read the data of the file, store in temporal structures
on memory, ask
the user and then, enter the data into the database. But the advantage of
using sqlite as
storage mechanism, as drh pointed out, is to use it as file format, an
avoid creating
intermediate data structures.
My opinion is that it is completely possible to live without nested
transactions, in
fact we all do now and survive, but they are very convenient to solve a
full range of
problems. You are right that a different range of problems can be easily
solved by just
maintaining a counter of transactions.
Written in an abstract form, you base your reasoning on the fact that
you know, before
beginning the first transaction, all the future steps that you are going
to perform and
the order of performing them. This is not always true, as some decisions
can be based on
external input, like an interative user, data coming from an external
source, other types
of events. Also, the decision is often taken based on the data itself, so
it is more
convenient to put the data in the database, operate with it and decide
after operation.
Finally, I am not advocating to include nested transactions into sqlite
or not, as this
is a problem to be solved by the people who is developing the library. But
it is important
to include all the facts in the discussion.
Best regards,
--
Compass Ing. y Sistemas Dr. Ramon Ribo
http://www.compassis.com[EMAIL PROTECTED]
c/ Tuset, 8 7-2 tel. +34 93 218 19 89
08006 Barcelona, Spain fax. +34 93 396 97 46
En Thu, 12 Apr 2007 00:37:21 +0200, Dennis Cote [EMAIL PROTECTED]
escribió:
Ramon Ribó wrote:
Imagine one application that can import data from a file. You want
that, in case of computer crash, either all the data of the file is
imported or none. At the same time, you want the user to manually
accept or reject every section of the file.
This example can be modelled in a very natural way with a transaction
covering the full file import and a nested transaction covering every
section.
Ramon,
I don't see that where nested transactions are needed for this example.
You seem to be suggesting a loop reading each file section and writing
it into the database in a nested transaction and then rolling back a
nested transaction if the user says they want to skip that section.
begin
for each section in file {
read section
begin nested
insert section
if promp_user(section) == keep
commit nested else
rollback nested
}
commit
The same thing can be done far more efficiently by prompting the user
first and only inserting the sections the user wants to keep.
begin
for each section in file {
read section
if promp_user(section) == keep
insert section
}
commit
If the program completes all users selected sections are inserted into
the database atomically. If the program crashes the entire file will be
deleted when the incomplete transaction is rolled back. Similarly if an
I/O error occur when reading the file or a disk full condition happens
when inserting a section, those and any other errors would cause the
transaction to be rolled back so that none of the file sections are
inserted. I want to insert all of the user selected sections or none of
them.
Nested transaction only create more work and make the application more
complicated.
Dennis Cote
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--
Compass Ing. y Sistemas Dr. Ramon Ribo
http://www.compassis.com[EMAIL PROTECTED]
c/ Tuset, 8 7-2 tel. +34 93 218 19 89
08006 Barcelona, Spain fax. +34 93 396 97 46
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[sqlite] New conflict clause: update
Hello, I was thinking on a new option that could be useful for sqlite. A new conflict clause called update so that the following SQL command: insert or update into table1 (a,b) values (1,2) was equivalent to update table1 set a=1,b=2 where ?unique-key-constraint? when a unique key contraint is hit. I think that it could have advantages over the replace conflict clause for the very usual case that a new record must be updated or inserted if it does not exist. What is your opinion on this? -- Compass Ing. y Sistemas Dr. Ramon Ribo http://www.compassis.com[EMAIL PROTECTED] c/ Tuset, 8 7-2 tel. +34 93 218 19 89 08006 Barcelona, Spain fax. +34 93 396 97 46 - To unsubscribe, send email to [EMAIL PROTECTED] -
Re: [sqlite] Data Dictionary in SQLite?
From what I know sqlite is not a DBRMS Thanks Is there an Oracle data-dictionary equivalent in SQLite? Ie. Is there something similar to SELECT * FROM ALL_TABLES to get information about tables in the database returned in row format? I know that I can use .tables or .dump to find out what is going on in the database, but I have a programmatic need to be able to detect if a particular table exists. Your advice, or pointing me to the proper documentation, would be greatly appreciated! Thanks, Daniel
[sqlite] aggregate funtion in the TCL binding
Hello,
It also looks to my that the interface should be something as as simple as:
db aggregate_function step_func final_func
But it seemed to me that all it should take is to create a normal TCL
function to be called for each row selected (say, to compute the sums
and squares and products), with some initialization code run before
the select, and some more code to run when the select is done (say, to
compute the correlation coeffiecient between two columns).
I would like to expain the type of problem that I am trying to solve in order to
recieve comments and opinions about its feasibility.
I work in the field of computer simulation for engineering, notably Finite
Element analysis. These types of problems have traditionally been solved
programming in either FORTRAN or C/C++ due to the big amount of
data to deal with and that they are very computer intensive. One run can
be of minutes, hours or even days.
The approach has some disadvantages. For example, the amount of developing
time just dedicated to deal with data structs is huge and also, any change
to the logic of the program can require a big amount of programming.
I want to experiment with a new way of dealing with the problem, by using
sqlite and a mixure of C++ and TCL.
Instead of just fetch data from the database and operate on it, I want to try
a different approach: make the process database driven.
So, instead of:
loop on select
do my algorithm
end loop
I want to try something like:
db eval {
select add_elem_k_triangle(e.num,
e.euler1,e.euler2,e.euler3,
m.units,m.thickness,m.specific_weight,m.E,m.nu,
n1.num*6,n2.num*6,n3.num*6,
n1.x,n1.y,n1.z,n2.x,n2.y,n2.z,n3.x,n3.y,n3.z)
from elements_triangles as e
join material_isotropic_shell as m on m.num = e.mat
join nodes as n1 on e.c1 = n1.num
join nodes as n2 on e.c2 = n2.num
join nodes as n3 on e.c3 = n3.num
}
where function add_elem_k_triangle is the one that make the
real algorithm work and can be implemented either in TCL or in C++
Currently add_elem_k_triangle is a normal function that operates on
external structures and has nothing to return for every element. I think
that in this case, it would be better that add_elem_k_triangle was an
aggregate function that returned something trivial, like the number of
elements that has operated with. In this way, A lot of void returns could
be avoided.
I understand that it is not simple to explain a problem like this in a few
lines but I hope that some big picture has been given.
What version are you looking at? The latest Tcl bindings already
do this.
I looked at version 3.2.1 and the code is:
static void tclSqlFunc(sqlite3_context *context, int argc, sqlite3_value**argv){
SqlFunc *p = sqlite3_user_data(context);
Tcl_DString cmd;
int i;
int rc;
Tcl_DStringInit(cmd);
Tcl_DStringAppend(cmd, p-zScript, -1);
for(i=0; iargc; i++){
if( SQLITE_NULL==sqlite3_value_type(argv[i]) ){
Tcl_DStringAppendElement(cmd, );
}else{
Tcl_DStringAppendElement(cmd, sqlite3_value_text(argv[i]));
}
}
rc = Tcl_Eval(p-interp, Tcl_DStringValue(cmd));
if( rc ){
sqlite3_result_error(context, Tcl_GetStringResult(p-interp), -1);
}else{
sqlite3_result_text(context, Tcl_GetStringResult(p-interp), -1,
SQLITE_TRANSIENT);
}
}
So, it uses strings for the arguments.
Best regards,
Compass Ing. y Sistemas
Dr. Ramon Ribó
http://www.compassis.com http://www.compassis.com/
[EMAIL PROTECTED] outbind://116/[EMAIL PROTECTED]
c/ Tuset, 8 7-2
tel. +34 93 218 19 89
08006 Barcelona, Spain
fax. +34 93 396 97 46
[sqlite] aggregate funtion in the TCL binding
Hello, Is there a way to define an aggregate function in the TCL binding? In case it is not there, would it be a nice addition for symmetry with the C-C++ interface? Also, I briefly reviewed the TCL binding C code and it looks like the function interface does not take advantage of the new features of sqlite version 3 with the integers and doubles, as it convert everything to one string. Are there any plans to change it? Regards, Compass Ing. y Sistemas Dr. Ramon Ribó http://www.compassis.com http://www.compassis.com/ [EMAIL PROTECTED] outbind://83/[EMAIL PROTECTED] c/ Tuset, 8 7-2 tel. +34 93 218 19 89 08006 Barcelona, Spain fax. +34 93 396 97 46
[sqlite] limiting database size
I would like to know if there is a way to limit a sqlite database and then be able to change this limit later on?
Re: [sqlite] limiting database size
On 7/11/05, Ramon [EMAIL PROTECTED] wrote: I would like to know if there is a way to limit a sqlite database and then be able to change this limit later on? Stop inserting when it's full? I want to put a limit like 10mb then later on e able to change this database limit to 15mb if I want to, is this possible?
[sqlite] download db - security question
I was wondering if someone can just download off my webpage the sqlite database. And if they can is there a way to block this type of download throw apache? Any tips and advices are welcome. Thanks, Ramon
Re: [sqlite] download db - security question
Thanks for all the help, I will be implementing this in the next couple of weeks in my project. Thanks again, Ramon On Mon, 2005-01-24 at 11:46 -0500, Jason Morehouse wrote: If using apache, this also works nice in your httpd.conf -- it allows you to put databases anywhere in the www root, without worrying about protecting specific directories. Files ~ .db Order allow,deny Deny from all Satisfy All /Files You'll also need to protect the (transient) rollback journal files. Perhaps: Files ~ .db-journal Order allow, deny Deny from all Satisfy All /Files
