RE: [sqlite] outputting select in cpp file?

[Pat Wibbeler]

Check out the callback parameter to sqlite_exec (the third parameter).
The quickstart gives an example of this:

http://www.sqlite.org/quickstart.html

Alternatively, check out sqlite3_prepare, sqlite3_bind, and
sqlite3_step, sqlite3_result*, and sqlite3_finalize.

All of these functions are documented here:
http://www.sqlite.org/capi3ref.html

Pat


-Original Message-
From: Keiichi McGuire [mailto:[EMAIL PROTECTED] 
Sent: Friday, July 28, 2006 3:36 PM
To: sqlite-users@sqlite.org
Subject: [sqlite] outputting select in cpp file?

This sounds like a very simple problem, but I cannot figure it out!

Basically what I have is this settings table that has a boolean data
type, and I want to check it via a cpp program.

sqlite_exec(db,"select flag from setting",0,0,);

and I want to be able to return a 0, or a 1 according to what I put into
the flag entry.

Thanks!
-Keiichi

[sqlite] Re: Project

[Cesar David Rodas Maldonado]

I found to give a preference to select and a delay to insert.
:D


On 7/27/06, Cesar David Rodas Maldonado <[EMAIL PROTECTED]> wrote:


If a SQLite Db is LOCKED can i exec an TRIGER?

Re: [sqlite] Sqlite flash and mallocs.

[drh]

[EMAIL PROTECTED] wrote:
> 
> Is it normal it takes 13,000 mallocs 
> 

That depends on your database schema and the data you
are storing.  
--
D. Richard Hipp   <[EMAIL PROTECTED]>

[sqlite] outputting select in cpp file?

[Keiichi McGuire]

This sounds like a very simple problem, but I cannot figure it out!

Basically what I have is this settings table that has a boolean data
type, and I want to check it via a cpp program.

sqlite_exec(db,"select flag from setting",0,0,);

and I want to be able to return a 0, or a 1 according to what I put into
the flag entry.

Thanks!
-Keiichi

[sqlite] Sqlite flash and mallocs.

[Mario . Hebert]

I am saving a simple database (4-5 tables and few records inside). The 
total size of the database once flashed is 9216 bytes.

I execute the following query:

snprintf(query, MAX_SQLITE_QUERY_LEN,
  "attach database %s as %s;"
  "BEGIN;"
  "create table if not exists %s.%s as select * from 
%s;" 
  "delete from %s.%s;"
  "insert into %s.%s select * from %s;"
  "COMMIT;"
  "detach database %s", 
  database, database,
  database, table, table,
  database, table,
  database, table, table,
  database );

Is it normal it takes 13,000 mallocs 

Our mallocs is not the fastest and well, as you can imagine it takes 
forever to flash it (even if it works!).

Mario Hebert
Legerity

Re: [sqlite] "SQL Error: near 'Table': Syntax error"

[Dennis Cote]

On 7/27/06, Peter van Dijk <[EMAIL PROTECTED]> wrote:




Using double quotes to quote identifiers in sqlite is dangerous, as
mistyping
a fieldname will not yield an error. Currently the only safe way to
quote
identifiers is using backticks, as in MySQL.



Sadly you are almost correct. :-(

Using the MS Access style square brackets for quoting also produces correct
error message for incorrect column names.

Unfortunately, an sqlite extension causes it to misinterpret non-existent
column names as string literals when they are quoted using SQL standard
double quotes.

The following trace shows the results for various styles of quotes.

   SQLite version 3.2.8
   Enter ".help" for instructions
   sqlite> create table t (a);
   sqlite> insert into t values(1);
   sqlite> select a from t;
   1
   sqlite> select c from t;
   SQL error: no such column: c
   sqlite> select "a" from t;
   1
   sqlite> select "c" from t;
   c
   sqlite> select 'a' from t;
   a
   sqlite> select 'c' from t;
   c
   sqlite> select `a` from t;
   1
   sqlite> select `c` from t;
   SQL error: no such column: c
   sqlite> select [a] from t;
   1
   sqlite> select [c] from t;
   SQL error: no such column: c

I'm sure this extension seemed like a good idea when it was introduced, but
this example shows the dangers of changing standard functionality to
"improve" it.

Now we are stuck using the non-standard quote characters introduced for
compatibility with other non-standard implementations in order to get
reliable error detection. Consequently, the SQL using these non-standard
quotes will not be portable to other standard conforming implementations.

The moral of this story is: stick to the standard unless you have a *VERY*
good reason to deviate.

Dennis Cote

Re: [sqlite] SQLite browser/manager + Deep SQL - testers please

[Me]

thanks
- Original Message - 
From: "Dennis Cote" <[EMAIL PROTECTED]>

To: 
Sent: Friday, July 28, 2006 12:00 PM
Subject: Re: [sqlite] SQLite browser/manager + Deep SQL - testers please



On 7/28/06, Me <[EMAIL PROTECTED]> wrote:


Also - How do I get it listed in the wiki - ManagementTools?



It's a wiki...

Just go to the page click the edit link and add it yourself.

HTH
Dennis Cote







No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.1.394 / Virus Database: 268.10.4/402 - Release Date: 7/27/2006

Re: [sqlite] User function in WHERE clause

[Stan]

O.K. This is what I need. Thanks
-- 
View this message in context: 
http://www.nabble.com/User-function-in-WHERE-clause-tf2009603.html#a5543377
Sent from the SQLite forum at Nabble.com.

Re: [sqlite] SQLite browser/manager + Deep SQL - testers please

[Dennis Cote]

On 7/28/06, Me <[EMAIL PROTECTED]> wrote:


Also - How do I get it listed in the wiki - ManagementTools?



It's a wiki...

Just go to the page click the edit link and add it yourself.

HTH
Dennis Cote

Re: [sqlite] User function in WHERE clause

[Dennis Cote]

On 7/28/06, Stan <[EMAIL PROTECTED]> wrote:



But there are my problems:
1) Return value xFunc is void? I have to return integer.
2) Where are described parameters in xFunc? E.g. what is it
"sqlite3_context"?



Stan,

Check out section 2.3  User defined funcion s on this page
http://www.sqlite.org/capi3.html

HTH
Dennis Cote

Re: [sqlite] WHERE with user function

[Dennis Cote]

On 7/28/06, Stan <[EMAIL PROTECTED]> wrote:



Is there any example (tutorial or explanation) in C or C++ for similar
problem?




Stan,

All the built in functions in sqlite use exactly the same API that is
available to you. The source file func.c conatins many examples of user
defined functions and returning values from these functions. You can view
the file here
http://www.sqlite.org/cvstrac/fileview?f=sqlite/src/func.c=1.132 or
download one of the source packages at http://www.sqlite.org/download.html.

HTH
Dennis Cote

[sqlite] SQLite browser/manager + Deep SQL - testers please

[Me]

Windows SQLite browser/manager.

Four query views. View/Edit four simultaneous queries or same table in 
various sort orders.
No limitation how a table is arranged for editing as long as the Primary Key 
is in the query.

Transactions supported.

Deep SQL: Work on blob-stored SQLite databases - down to any level.
Edit blobs as if a local file - Excel®, Word®, Photoshop®, etc...

Save queries, Lookup list, Ditto columns and save column view widths.

Table tool: create, rename and drop.
Column tool: add, drop, rename, reorder and redefine (change type, default, 
check(), constraints).

Index tool: create, rename and drop.

www.sqlight.com

I'd appreciate it anyone has the time to test.
Also - How do I get it listed in the wiki - ManagementTools?

Windows Only!

[EMAIL PROTECTED]
StanDurham

[sqlite] Re: User function in WHERE clause

[Igor Tandetnik]

Stan <[EMAIL PROTECTED]> wrote:

Thanks for answer. Yes, I have read this many times, but...
...I'm dumb maybe.
I understand first 5 parameters in the "sqlite3_create_function".
xStep and xFinal will be NULL.

But there are my problems:
1) Return value xFunc is void? I have to return integer.


sqlite3_result_int


2) Where are described parameters in xFunc? E.g. what is it
"sqlite3_context"?


An opaque handle you pass to sqlite3_result_* and sqlite3_user_data.

The second parameter of xFunc is the number of values in the array 
pointed to by the third parameter. The third is an array of 
sqlite3_value* pointers, each representing a parameter to the function 
from SQL invocation. You can read the actual values using 
sqlite3_value_* functions.


Igor Tandetnik 

Re: [sqlite] WHERE with user function

[Christian Smith]

Stan uttered:



Hi,
I need user function for WHERE clause.
But I don't know what type of parameters to use for such function:

SELECT * FROM Table WHERE MYFUNC(ColumnName, IntValue).

Above all - how to returm value to WHERE and what type?
Is there any example (tutorial or explanation) in C or C++ for similar
problem?



You've checked out the API reference?
http://www.sqlite.org/capi3ref.html#sqlite3_create_function




Thanks
Stan



--
/"\
\ /ASCII RIBBON CAMPAIGN - AGAINST HTML MAIL
 X   - AGAINST MS ATTACHMENTS
/ \

Re: [sqlite] User function in WHERE clause

[Stan]

Thanks for answer. Yes, I have read this many times, but... 
...I'm dumb maybe.
I understand first 5 parameters in the "sqlite3_create_function".
xStep and xFinal will be NULL.

But there are my problems:
1) Return value xFunc is void? I have to return integer.
2) Where are described parameters in xFunc? E.g. what is it
"sqlite3_context"?

Thanks for your time.

Stan
-- 
View this message in context: 
http://www.nabble.com/User-function-in-WHERE-clause-tf2009603.html#a5542532
Sent from the SQLite forum at Nabble.com.

[sqlite] Re: User function in WHERE clause

[Igor Tandetnik]

Stan <[EMAIL PROTECTED]> wrote:

Thanks for tip. I'm happy to see it's possible.
Alas, I'm rather confused. I have read documentation,
but I'm not sure what parameters to use


What parameters your function needs to take depends entirely on what 
said function is supposed to do.



and what return
value for WHERE clause.


Return an integer: 0 means false, any non-zero value means true.


And how to include MYFUNC to SQLite ?


Have you read the documentation Jay Sprankle pointed you to? 
http://sqlite.org/capi3ref.html#sqlite3_create_function


Igor Tandetnik 

Re: [sqlite] insert default values

[Mario Frasca]

On 2006-0728 16:47:21, Nemanja Corlija wrote:
> You can get that with this query:
>  select seq from sqlite_sequence where name='test' [...]
> 
> There is also a last_insert_rowid() [...]
> sqlite_sequence is really the way to go.

very useful comments from everybody,
thanks!  

Mario

-- 
 Power corrupts. Absolute power is kind of neat.

[sqlite] Please un subscribe me from sqlite. Dont send me email

[prabhu kumaravelu]

Please un subscribe me from sqlite



From: "Rob Richardson" <[EMAIL PROTECTED]>
Reply-To: sqlite-users@sqlite.org
To: 
Subject: [sqlite] The meaning of times in julianday()
Date: Fri, 28 Jul 2006 10:50:52 -0400

Greetings!



My test query is:



select tag_key,value,

   datetime(value_timestamp, 'localtime') AS localtime,

   datetime(value_timestamp) AS UTCtime

from trend_view

where trend_key=1

and value_timestamp >= julianday('2006-07-27 10:08:32.000')

order by value_timestamp desc



My table has records recorded every hour, roughly on the hour.  This
program that generated this query wanted to get the last 24 hours' worth
of data.  It was run at 10:08 on June 28th.



The earliest data returned was recorded at 11:01 UTC on June 27th, or
7:01 AM EDT on June 27th.  That's too far back by four hours (the
difference between EDT and UTC time).



When I changed the query to use julianday('2006-07-27 10:08:32.000',
'utc'), the earliest data returned was recorded at 15:01 UTC on June
27th, which is 11:01 EDT on June 27th, which is what I want.



When I changed the query to use julianday('2006-07-27 10:08:32.000',
'localtime'), the earliest data returned was recorded at 07:01 UTC on
June 27th, which is 03:01 AM EDT on June 27th, which is far too much.



So, I conclude the following:

If no modifier is provided to the julianday() method, the given date is
assumed to be UTC.

If the 'utc' modifier is used, the given date is assumed to be local
time.  It is converted to UTC before the comparison is made.

If the 'localtime' modifier is used, the given date is assumed to be UTC
time, and it is converted to local time before the comparison is made.

Are those conclusions correct?  And I presume the datetime() method
operates the same way?



Thanks again!



Rob Richardson

RAD-CON INC.





_
Who will win Bollywood’s most coveted IIFA awards? You decide! Cast your 
vote! http://server1.msn.co.in/sp06/IIFA2006/static/weekend.asp

[sqlite] The meaning of times in julianday()

[Rob Richardson]

Greetings!

 

My test query is:

 

select tag_key,value,

   datetime(value_timestamp, 'localtime') AS localtime,

   datetime(value_timestamp) AS UTCtime  

from trend_view

where trend_key=1 

and value_timestamp >= julianday('2006-07-27 10:08:32.000') 

order by value_timestamp desc

 

My table has records recorded every hour, roughly on the hour.  This
program that generated this query wanted to get the last 24 hours' worth
of data.  It was run at 10:08 on June 28th.  

 

The earliest data returned was recorded at 11:01 UTC on June 27th, or
7:01 AM EDT on June 27th.  That's too far back by four hours (the
difference between EDT and UTC time).

 

When I changed the query to use julianday('2006-07-27 10:08:32.000',
'utc'), the earliest data returned was recorded at 15:01 UTC on June
27th, which is 11:01 EDT on June 27th, which is what I want.  

 

When I changed the query to use julianday('2006-07-27 10:08:32.000',
'localtime'), the earliest data returned was recorded at 07:01 UTC on
June 27th, which is 03:01 AM EDT on June 27th, which is far too much.

 

So, I conclude the following:

If no modifier is provided to the julianday() method, the given date is
assumed to be UTC.

If the 'utc' modifier is used, the given date is assumed to be local
time.  It is converted to UTC before the comparison is made.

If the 'localtime' modifier is used, the given date is assumed to be UTC
time, and it is converted to local time before the comparison is made.

Are those conclusions correct?  And I presume the datetime() method
operates the same way?

 

Thanks again!

 

Rob Richardson

RAD-CON INC.

 

Re: [sqlite] insert default values

[Nemanja Corlija]

On 7/28/06, Mario Frasca <[EMAIL PROTECTED]> wrote:

On 2006-0728 16:07:47, Nemanja Corlija wrote:
> You can insert default value like this:
>  insert into test (f) values (NULL);
>
> Inserting NULL into autoincrement field just increments it. While
> omitting value for any other field uses default for that field, if one
> is defined.

next question: is there a way to ask which was the last (autoincremented)
value inserted in the table?  or is there a guarantee that this works,
as it seems...

select max(f) from test;


You can get that with this query:
 select seq from sqlite_sequence where name='test'

'test' is the name of your table and "seq" field keeps the
last/highest value that was inserted in AUTOINCREMENT field.

This will only work if you define your table to use true AUTOINCREMENT
field, like we did in this example. If you use just INTEGER PRIMARY
KEY, without AUTOINCREMENT, that  table doesn't have a record in
sqlite_sequence table. For the later case "select max(f) from test;"
would work. Though that's not what we have here.

There is also a last_insert_rowid() function that is like an alias for
sqlite_last_insert_rowid() API function and it works per db
connection. I don't think this this is very useful with true
AUTOINCREMENT fields, so sqlite_sequence is really the way to go.

--
Nemanja Corlija <[EMAIL PROTECTED]>

RE: [sqlite] Can I use internal variables in SQL scripts?

[Rob Richardson]

Christian,

Thank you for your reply.  I will be happy to develop stored procedure
capability for SQLite in my copious spare time.  :-)

Don't hold your breath.

RobR


-Original Message-
From: Christian Smith [mailto:[EMAIL PROTECTED] 
Sent: Friday, July 28, 2006 10:10 AM
To: sqlite-users@sqlite.org
Subject: Re: [sqlite] Can I use internal variables in SQL scripts?

No, because SQLite has no stored procedure capabilities. SQLite has only

simple SQL statements. I'm sure the community would welcome such an 
addition, should you or anyone else fancy contributing them:)

Re: [sqlite] insert default values

[Mario Frasca]

Hi Gerry, yes, your help was quite useful...

now we have two problems here, I would say:

the first one is that, of all the things you have tried, only one is
correct but two more are accepted without causing an error.

On 2006-0728 06:55:22, Gerry Snyder wrote:
> sqlite> create table test(f int auto_increment primary key, v int 
> default 0);
-- no error, not working  (I would expect either a syntax error or a
'auto_increment only on integer')
> --
> sqlite> create table test(f integer auto_increment primary key, v int 
> default 0);
-- no error, not working (I would expect either a syntax error or
complete equivalence with the working version)
> --
> sqlite> create table test(f integer primary key auto_increment, v int 
> default 0);
> SQL error: near "auto_increment": syntax error
> 
> sqlite> create table test(f int autoincrement primary key, v int default 0);
> SQL error: near "autoincrement": syntax error
> -
> sqlite> create table test(f int primary key autoincrement, v int default 0);
> SQL error: AUTOINCREMENT is only allowed on an INTEGER PRIMARY KEY
> --
> sqlite> create table test(f integer primary key autoincrement, v int 
> default 0);
-- all right, this is the only working one, thanks a lot!

the next problem is that I still would like to 
insert into test () values ();
or maybe
insert into test default values;

here sqlite does respond clearly:
sqlite> insert into test () values ();
SQL error: near ")": syntax error
sqlite> insert into test default values;
SQL error: near "default": syntax error

is it possible to do this in sqlite?

Mario

-- 
 Gotta run, my government's collapsing.

Re: [sqlite] insert default values

[Nemanja Corlija]

On 7/28/06, Gerry Snyder <[EMAIL PROTECTED]> wrote:

Finally, get it right:
sqlite> create table test(f integer primary key autoincrement, v int
default 0);
sqlite> insert into test (v) values (1);
sqlite> insert into test (v) values (2);
sqlite> insert into test (v) values (NULL);
sqlite> select * from test;
1|1
2|2
3|

Not sure why the last row is not 3|0.


Because NULL is allowed for field in question.
You can insert default value like this:
 insert into test (f) values (NULL);

Inserting NULL into autoincrement field just increments it. While
omitting value for any other field uses default for that field, if one
is defined.

--
Nemanja Corlija <[EMAIL PROTECTED]>

Re: [sqlite] Can I use internal variables in SQL scripts?

[Christian Smith]

Rob Richardson uttered:


In SQL Server, I can write a stored procedure that looks something like
this:

[snip]


Other features available in SQL Server stored procedures include while
loops, temporary tables, and the FETCH command to retrieve data from a
resultset one row at a time.


I have SQLite Explorer and SQLiteSpy.  Does either one have similar
capabilities?



No, because SQLite has no stored procedure capabilities. SQLite has only 
simple SQL statements. I'm sure the community would welcome such an 
addition, should you or anyone else fancy contributing them:)







Thanks very much!



Rob Richardson

RAD-CON, Incv.










--
/"\
\ /ASCII RIBBON CAMPAIGN - AGAINST HTML MAIL
 X   - AGAINST MS ATTACHMENTS
/ \

Re: [sqlite] insert default values

[Gerry Snyder]

Mario Frasca wrote:


and how do I insert a 'all-default' record?
  

After getting everything else right (see my previous post):

sqlite> insert into test (f) values (NULL);
sqlite> select * from test;
1|1
2|2
3|
4|0

And this answers my previous comment, too. Inserting a NULL into v 
overrides the default.


Gerry

Re: [sqlite] insert default values

[Christian Smith]

Gerry Snyder uttered:


Finally, get it right:
sqlite> create table test(f integer primary key autoincrement, v int default 
0);

sqlite> insert into test (v) values (1);
sqlite> insert into test (v) values (2);
sqlite> insert into test (v) values (NULL);
sqlite> select * from test;
1|1
2|2
3|

Not sure why the last row is not 3|0.



Because you've explicitly inserted a NULL. The default value is only used 
if the column is not explicitly specified in the insert.





HTH,

Gerry



--
/"\
\ /ASCII RIBBON CAMPAIGN - AGAINST HTML MAIL
 X   - AGAINST MS ATTACHMENTS
/ \

Re: [sqlite] insert default values

[Gerry Snyder]

Mario Frasca wrote:

I'm trying to use default values and autoincrementing primary keys.

[EMAIL PROTECTED]:~$ sqlite3 /data/mariof/test.db_scia.db
SQLite version 3.3.4
Enter ".help" for instructions
sqlite> create table test(f int auto_increment primary key, v int default 0);
  

The above is not correct syntax for what you want.

sqlite> insert into test (v) values (1);
sqlite> insert into test (v) values (2);
sqlite> insert into test (v) values (1);
sqlite> insert into test (v) values (NULL);
sqlite> select * from test;
|1
|2
|1
|
  

First, recreating your example:
$ sqlite3
SQLite version 3.3.6
Enter ".help" for instructions
sqlite> create table test(f int auto_increment primary key, v int 
default 0);

sqlite> insert into test (v) values (1);
sqlite> insert into test (v) values (2);
sqlite> insert into test (v) values (NULL);
sqlite> select * from test;
|1
|2
|
--
Next, showing that f is really not what you want:
sqlite> select oid,f,v from test;
1||1
2||2
3||
sqlite> drop table test;
--
Next, correcting int to integer (no change.. yet)
sqlite> create table test(f integer auto_increment primary key, v int 
default 0)

;
sqlite> insert into test (v) values (1);
sqlite> insert into test (v) values (2);
sqlite> insert into test (v) values (NULL);
sqlite> select * from test;
|1
|2
|
sqlite> drop table test;
--
Now, correcting the order:
sqlite> create table test(f integer primary key auto_increment, v int 
default 0);

SQL error: near "auto_increment": syntax error

Now correct the spelling of autoincrement:
sqlite> create table test(f int autoincrement primary key, v int default 0);
SQL error: near "autoincrement": syntax error
-
Now correct the order again:
sqlite> create table test(f int primary key autoincrement, v int default 0);
SQL error: AUTOINCREMENT is only allowed on an INTEGER PRIMARY KEY
--
Finally, get it right:
sqlite> create table test(f integer primary key autoincrement, v int 
default 0);

sqlite> insert into test (v) values (1);
sqlite> insert into test (v) values (2);
sqlite> insert into test (v) values (NULL);
sqlite> select * from test;
1|1
2|2
3|

Not sure why the last row is not 3|0.

HTH,

Gerry

[sqlite] Can I use internal variables in SQL scripts?

[Rob Richardson]

In SQL Server, I can write a stored procedure that looks something like
this:

 

CREATE PROCEDURE MyProc AS

DECLARE @someVariable INT

SELECT @someVariable = someColumn FROM someTable WHERE
someConditionThatReturnsOneRow

SELECT someOtherColumn FROM someOtherTable WHERE thePrimaryKey =
@someVariable

END PROCEDURE

 

Other features available in SQL Server stored procedures include while
loops, temporary tables, and the FETCH command to retrieve data from a
resultset one row at a time.  

 

I have SQLite Explorer and SQLiteSpy.  Does either one have similar
capabilities?

 

Thanks very much!

 

Rob Richardson

RAD-CON, Incv.

 

 

 

[sqlite] WHERE with user function

[Stan]

Hi,
I need user function for WHERE clause.
But I don't know what type of parameters to use for such function:

SELECT * FROM Table WHERE MYFUNC(ColumnName, IntValue).

Above all - how to returm value to WHERE and what type?
Is there any example (tutorial or explanation) in C or C++ for similar
problem?

Thanks
Stan
-- 
View this message in context: 
http://www.nabble.com/WHERE-with-user-function-tf2015394.html#a5539399
Sent from the SQLite forum at Nabble.com.

Re: [sqlite] Problem parsing comments from SQL?

[drh]

Jeff Nokes <[EMAIL PROTECTED]> wrote:
> Hi,
> I've run into a weird situation where SQLite seems to not like in-line 
> comments depending on where they are placed. 

This is not the SQLite core but the sqlite command-line shell.
The command line shell accumulates input until it sees a line that
ends with a semicolon.  If an input line ends with a semicolon
and the accumulated input passes the sqlite3_complete() test, only
then is the input passed into the sqlite core to be processed.

By putting comments after the semicolons, you are hiding the
semicolons from the command-line shell and causing the input
processing to be deferred.

To insure that input has been processed, put a semicolon on
a line by itself.  Extra semicolons will not hurt anything.
--
D. Richard Hipp   <[EMAIL PROTECTED]>

Re: [sqlite] Another question about RAM

[drh]

"Sarah" <[EMAIL PROTECTED]> wrote:
> Can anyone give me some guide?
> 

SQLite memory requirements depends on how it is compiled
and how it is used.  You should use experiments to determine
how much memory is required for your particular project.

If SQLITE_ENABLE_MEMORY_MANAGEMENT is defined when you
compile, then the global variable contains the highwater
mark of your total heap memory utilization.

> 
> - Original Message - 
> From: "Sarah" <[EMAIL PROTECTED]>
> To: 
> Sent: Thursday, July 27, 2006 3:47 PM
> Subject: [sqlite] Another question about RAM
> 
> 
> > Hi, all
> > 
> > I want to build SQLite on the uc/os-II kernel in an embedded device.
> > 
> > Because uc/os-II doesn't provide malloc(), free() to manage memory, instead,
> > it divides the memory into fixed-length blocks and provides OSMemGet() and 
> > OSMemPut() to 
> > get and put fixed-length memory block.
> > 
> > In order to port SQLite, I have to wrap uc/os-II with a set of standard 
> > memory management APIs(malloc, free...).
> > So I need to decide in advance that which 'fixed length' will be better. 
> > That is to say, when using malloc() to 
> > allocate memory in SQLite, how much memory is needed in most cases? what 
> > does it depend on?
> > 
> > Thanks.
> > 
> >

Re: [sqlite] sqlite using whole-file (not byte-range) locking

[drh]

Adam Megacz <[EMAIL PROTECTED]> wrote:
> I'm interested in using SQLite with AFS (the Andrew FileSystem).
> Unlike NFS, AFS has solid, reliable support for *whole-file* advisory
> locking across the network.
> 
> AFS does some very sophisticated caching, so an SQLite database in AFS
> accessed by a single reader/writer would be very efficient.  A second
> reader/writer would cause performance to degrade by breaking callbacks
> quite often, but as long as whole-file locking is used, no corruption
> should occur.
> 
> I think a scenario where a database is accessed mostly by a single
> process but occasionally updated by other clients (for example, for
> administration) would work really well.  In a lot of applications
> (like the one I'm considering) this would eliminate the need for an
> "administration API" implemented on the main reader/writer --
> administration could be done using the sqlite3 binary directly on the
> database across AFS.
> 
> I read through the locking code:
> 
>   http://www.srcdoc.com/sqlite_3.2.2/os__unix_8c-source.html#l00911
> 
> It looks like it would be possible to do the locking with whole-file
> locks on three separate files (less elegant, certainly) rather than
> byte range locks if one gave up support for old versions of Windows.
> 
> Does this sound like it would work?  Can anybody see any way to do it
> with less than three files?  AFS offers both read-locks and
> exclusive-write-locks on all platforms via fcntl().
> 

In the latest versions of SQLite (3.3.0 and later) you can provide
SQLite with customized locking code at run-time.  So you can
easily add AFS support that uses whole-file locking instead of
the goofy byte-range stuff I have to do for Win95.

I expect that code to handle additional locking styles (such
as separate lock-file locks for broken NFS systems or for file 
systems that do not support any kind of locking natively) will
be added to the standard SQLite distribution in the near future.
If you can wait, you might want to add AFS locking to that
module as another option.
--
D. Richard Hipp   <[EMAIL PROTECTED]>

Re: [sqlite] Another question about RAM

[Martin Jenkins]

Sarah wrote:
>> Because uc/os-II doesn't provide malloc(), free() to manage memory,
>> instead, it divides the memory into fixed-length blocks and
>> provides OSMemGet() and OSMemPut() to get and put fixed-length
>> memory block.
>> 
>> In order to port SQLite, I have to wrap uc/os-II with a set of
>> standard memory management APIs(malloc, free...). So I need to
>> decide in advance that which 'fixed length' will be better. That is
>> to say, when using malloc() to allocate memory in SQLite, how much
>> memory is needed in most cases? what does it depend on?

I suspect nobody really knows. I don't know your platform but you might
have some luck compiling a debugging malloc library that gives you some
stats. http://www-128.ibm.com/developerworks/linux/library/l-debug/
describes a couple - the MEMWATCH or YAMD tools might do what you want.

There might be some utility in building sqlite on a Linux box with the
above libraries. You could put a thin wrapper around calls to malloc,
run some queries and dump the stats to a file for analysis.

Martin

Re: [sqlite] Another question about RAM

[Sarah]

Can anyone give me some guide?


- Original Message - 
From: "Sarah" <[EMAIL PROTECTED]>
To: 
Sent: Thursday, July 27, 2006 3:47 PM
Subject: [sqlite] Another question about RAM


> Hi, all
> 
> I want to build SQLite on the uc/os-II kernel in an embedded device.
> 
> Because uc/os-II doesn't provide malloc(), free() to manage memory, instead,
> it divides the memory into fixed-length blocks and provides OSMemGet() and 
> OSMemPut() to 
> get and put fixed-length memory block.
> 
> In order to port SQLite, I have to wrap uc/os-II with a set of standard 
> memory management APIs(malloc, free...).
> So I need to decide in advance that which 'fixed length' will be better. That 
> is to say, when using malloc() to 
> allocate memory in SQLite, how much memory is needed in most cases? what does 
> it depend on?
> 
> Thanks.
> 
>

[sqlite] insert default values

[Mario Frasca]

I'm trying to use default values and autoincrementing primary keys.

[EMAIL PROTECTED]:~$ sqlite3 /data/mariof/test.db_scia.db
SQLite version 3.3.4
Enter ".help" for instructions
sqlite> create table test(f int auto_increment primary key, v int default 0);
sqlite> insert into test (v) values (1);
sqlite> insert into test (v) values (2);
sqlite> insert into test (v) values (1);
sqlite> insert into test (v) values (NULL);
sqlite> select * from test;
|1
|2
|1
|

I'm not a great fan of the auto_increment feature, I like sequences a
lot better, but as sqlite recognizes it, does it also implement it?  the
documentation states "the requested feature was added in 3.1", I'm
testing with 3.3.4...

and how do I insert a 'all-default' record?

sqlite> insert into test default values;
SQL error: near "default": syntax error
sqlite> insert into test () values ();
SQL error: near ")": syntax error

actually, missing auto_increment and sequences, inserting an 'all default'
record is just a style exercise, not really particularly useful...

thanks,
Mario Frasca

-- 
Die Welt wird nicht bedroht von den Menschen, die böse sind, sondern
von denen, die das Böse zulassen
  -- Albert Einstein

Re: [sqlite] User function in WHERE clause

[Stan]

Thanks for tip. I'm happy to see it's possible.
Alas, I'm rather confused. I have read documentation,
but I'm not sure what parameters to use and what return 
value for WHERE clause. Can you be so kind and show 
me a skeleton (C++) function for this:
SELECT * FROM Table WHERE MYFUNC(ColumnName, IntValue) ?
And how to include MYFUNC to SQLite ?

... you see - troubles of a beginner :-).

Thanks

Stan
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