when I create a db on a file system, I guess a query process has to go
through 2 levels of seeks ?
first sqlite finds the B-tree node that stores the index to the file
offset of my desired record, then sqlite uses that offset to make
syscall seek(offset),
then Kernel consults the FS implementation
On 11/19/2010 05:22 AM, Duquette, William H (316H) wrote:
> On 11/18/10 2:16 PM, "Drake Wilson" wrote:
>
> Quoth "Duquette, William H (316H)", on
> 2010-11-18 14:08:10 -0800:
>> It seems to me that it shouldn't be necessary for SQLite to evaluate
>> FOO's comparison function when doing queries on
Nikolaus Rath wrote:
> I understand that running INSERT or DELETE during an active SELECT query
> can get me into trouble. But is it safe to run (in pseudocode):
>
> for value in "SELECT main_column IN mytable":
>
> UPDATE mytable SET other_column='foobar' WHERE main_column=value
It should be
Hello,
I understand that running INSERT or DELETE during an active SELECT query
can get me into trouble. But is it safe to run (in pseudocode):
for value in "SELECT main_column IN mytable":
UPDATE mytable SET other_column='foobar' WHERE main_column=value
?
Thanks,
-Nikolaus
--
»Time
On 11/18/10 2:16 PM, "Drake Wilson" wrote:
Quoth "Duquette, William H (316H)" , on
2010-11-18 14:08:10 -0800:
> It seems to me that it shouldn't be necessary for SQLite to evaluate
> FOO's comparison function when doing queries on mytable; the
> collation order should be implicit in the mykey co
Quoth "Duquette, William H (316H)" , on
2010-11-18 14:08:10 -0800:
> It seems to me that it shouldn't be necessary for SQLite to evaluate
> FOO's comparison function when doing queries on mytable; the
> collation order should be implicit in the mykey column's index. Is
> this in fact the case?
W
Suppose I define a custom collating sequence FOO, and use it on an indexed
column:
CREATE TABLE mytable (mykey TEXT PRIMARY KEY COLLATE FOO, ...)
It seems to me that it shouldn't be necessary for SQLite to evaluate FOO's
comparison function when doing queries on mytable; the collation order
Hello Prakash,
What kind of drive is it? My experience is that SATA drives hate being
banged on from multiple threads. They just can't handle multiple
simultaneous work loads without slowing down drastically. They're fine
with heavy duty single threaded IO. In my application, I serialize
most heav
Hi,
I have a database placed on a shared drive.
Two processes (from different hosts) do a bunch of select commands.
I have a busy handler that sleeps of 1 second in each attempt and bails out
after 10 attempts.
The observation is that, if only one process is running (on any host) the
results a
Wow. Thanks. I see now that this is mentioned in the docs on the page for
the VACUUM statement. It really should be mentioned on the CREATE TABLE
page also where the rowid is explained. This is important information for
people who are learning SQLite and trying to figure out how to design thei
As someone who just started using SQLite without any previous background in
SQL, it was confusing to me. I did a search on nabble through this mailing
list and see now that I'm not the first person to ask about this issue.
IMO, it would be helpful to people new to SQLite to mention this in the d
On Wed, Nov 17, 2010 at 04:36:12PM -0600, Bernard Ertl scratched on the wall:
> Is it not possible to reference the SQLite
> internal/default column for the RowID in a foreign key definition?
Even if you could, you don't want to do this.
Unless you define an ROWID alias (i.e. an INTEGER
On Wed, 17 Nov 2010 16:36:12 -0600, "Bernard Ertl"
wrote:
>I'm getting a "foreign key mismatch" error with the following code:
>
>~~~
>
>PRAGMA foreign_keys = ON;
>
>CREATE TABLE IF NOT EXISTS JobPlans (Name UNIQUE);
>
>CREATE TABLE IF NOT EXISTS Tasks (JobPlan_ID INTEGER NOT NULL REFERENCES
>Jo
On 18 Nov 2010, at 1:22pm, Joseph Garry wrote:
>> From: itandet...@mvps.org
>> Joseph Garry wrote:
>>> I'd like to set up a compiled sqllite (sqlite3_prepare_v2) statement with a
>>> query like
>>> 'select tabid, col1, col2 from table where tabid in (?)'
>>> But how do I bind in the parameter h
That would work, but the thing I'm after here is speed. And I can't imagine
what you're suggesting would be very fast. Am I mistaken?
> To: sqlite-users@sqlite.org
> From: itandet...@mvps.org
> Date: Thu, 18 Nov 2010 08:08:51 -0500
> Subject: Re: [sqlite] select where value in
>
> Joseph Garry
Joseph Garry wrote:
> I'd like to set up a compiled sqllite (sqlite3_prepare_v2) statement with a
> query like
> 'select tabid, col1, col2 from table where tabid in (?)'
> But how do I bind in the parameter here? An example would be welcome, of
> course.
You can't do that directly. One way is t
I'd like to set up a compiled sqllite (sqlite3_prepare_v2) statement with a
query like
'select tabid, col1, col2 from table where tabid in (?)'
But how do I bind in the parameter here? An example would be welcome, of
course.
_
Yang wrote:
> for a row, and one column (most likely blob type), I want to append
> some value to the end of the blob, I do this many times. then I may
> read up all the appended sections and write out the entire blob with a
> new value
BLOB API:
http://www.sqlite.org/c3ref/blob_open.html
--
Hi Jeff,
I haven't actually tried it, but just by inspection I would guess that a view
can't refer to another column within itself, so there are 2 options.
Create a second view on top of the first view. (I've not tested this - note how
the view name is aliased to just 'Patterns' because I'm laz
On 17 November 2010 22:13, Jeff Archer wrote:
> First let me say thank you to all for the very good support that receive here.
>
> I have the these tables and view
>
.
.
.
>
> I would like to add these calculated columns to my view but not sure how to
> make
> this work.
>
> Patterns.wMicr
On Tue, Nov 16, 2010 at 04:08:16PM +0300, Ruslan Mullakhmetov scratched on the
wall:
> i got following contradictory replies to my question
>
> > if i execute query like " insert into tbl( filed ) VALUES ( 1 ); Select
> > last_insert_rowid() as li;" would be it atomic? or it anyway would suffe
Simon - thanks v. much. Makes complete sense now - and it does precisely
what I wanted. :)
{Appreciate the tip on the index - performance hasn't been an issue yet but
I'm sure I'll end up using it.}
On Wed, Nov 17, 2010 at 12:51 PM, Simon Slavin wrote:
>
> On 16 Nov 2010, at 3:29pm, Amit Chaudh
I'm getting a "foreign key mismatch" error with the following code:
~~~
PRAGMA foreign_keys = ON;
CREATE TABLE IF NOT EXISTS JobPlans (Name UNIQUE);
CREATE TABLE IF NOT EXISTS Tasks (JobPlan_ID INTEGER NOT NULL REFERENCES
JobPlans(RowID) ON DELETE CASCADE, UID UNIQUE NOT NULL);
INSERT INTO Jo
First let me say thank you to all for the very good support that receive here.
I have the these tables and view
// Patterns table
CREATE TABLE IF NOT EXISTS [Patterns] (
PatternID INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
Name VARCHAR NOT NULL UNIQUE,
Description VARCHAR NOT NULL
On Thu, 18 Nov 2010 01:45:22 -0800, Yang
wrote:
>I wonder if I can do this efficiently in sqlite:
>
>for a row, and one column (most likely blob type), I want to append
>some value to the end of the blob, I do this many times. then I may
>read up all the appended sections and write out the entir
I wonder if I can do this efficiently in sqlite:
for a row, and one column (most likely blob type), I want to append
some value to the end of the blob, I do this many times. then I may
read up all the appended sections and write out the entire blob with a
new value
without any special support,
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