Re: [sqlite] Transaction isolation

Roger Binns wrote: > Yang Zhang wrote: >> Actually, this is only because Python 3 str is Python 2 unicode. Python >> 2 (which I'm currently using, and which I believe most of the world is >> using) str is a physical string of bytes, not a logical/decoded >> character string. Python 2.6

Re: [sqlite] Transaction isolation

-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Yang Zhang wrote: > Actually, this is only because Python 3 str is Python 2 unicode. Python > 2 (which I'm currently using, and which I believe most of the world is > using) str is a physical string of bytes, not a logical/decoded > character

Re: [sqlite] Transaction isolation

Igor Tandetnik wrote: > Yang Zhang wrote: >> Pavel Ivanov wrote: >>> BTW, ACID that you mentioned has nothing to do with snapshot >>> isolation that you want to achieve. AFAIK only Oracle supports this >>> kind of statement isolation level. >> Actually, Oracle, Postgresql,

Re: [sqlite] Transaction isolation

Yang Zhang wrote: > Pavel Ivanov wrote: >> BTW, ACID that you mentioned has nothing to do with snapshot >> isolation that you want to achieve. AFAIK only Oracle supports this >> kind of statement isolation level. > > Actually, Oracle, Postgresql, SQL Server, Firebird, and

Re: [sqlite] Transaction isolation

Pavel Ivanov wrote: > BTW, ACID that you mentioned has nothing to do with snapshot isolation > that you want to achieve. AFAIK only Oracle supports this kind of > statement isolation level. Actually, Oracle, Postgresql, SQL Server, Firebird, and others support snapshot isolation.

Re: [sqlite] Transaction isolation

Roger Binns wrote: > Yang Zhang wrote: >> I copied and pasted this code straight from my actual application, which >> uses blobs instead of integers, which I need to convert into strings >> (since Python interfaces with blobs using the `buffer` type, not `str`). > > And for very good reason.

Re: [sqlite] Transaction isolation

D. Richard Hipp wrote: > On May 18, 2009, at 1:13 PM, John Elrick wrote: > > >> John Elrick wrote: >> >>> SNIP >>> >>> > I say this because your example implies that the Python wrapper > starts > the transaction automatically inside the execute, and I would not >

Re: [sqlite] Transaction isolation

-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Yang Zhang wrote: > I copied and pasted this code straight from my actual application, which > uses blobs instead of integers, which I need to convert into strings > (since Python interfaces with blobs using the `buffer` type, not `str`). And for

Re: [sqlite] Transaction isolation

-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 John Elrick wrote: > Are you certain the wrapper is behaving that way? The pysqlite wrapper (available as a sqlite3 Python module) by default parses your SQL and starts and ends transactions behind your back, in order to make it look like SQLite

Re: [sqlite] Transaction isolation

On May 18, 2009, at 1:13 PM, John Elrick wrote: > John Elrick wrote: >> SNIP >> I say this because your example implies that the Python wrapper starts the transaction automatically inside the execute, and I would not be surprised if it did so BEFORE executing the SQL

Re: [sqlite] Transaction isolation

John Elrick wrote: > SNIP > >>> I say this because your example implies that the Python wrapper starts >>> the transaction automatically inside the execute, and I would not be >>> surprised if it did so BEFORE executing the SQL parameter. >>> >>> >> The cursor() method that I call

Re: [sqlite] Transaction isolation

SNIP >> I say this because your example implies that the Python wrapper starts >> the transaction automatically inside the execute, and I would not be >> surprised if it did so BEFORE executing the SQL parameter. >> > > The cursor() method that I call on the conn for the SELECT should give

Re: [sqlite] Transaction isolation

SQLite doesn't support several simultaneous transactions on the same connection to database. So in fact your select and insert statements execute in the same transaction. And even more: your inserts are not committed until your select is completely finished. So for your task you should use

Re: [sqlite] Transaction isolation

Yang Zhang wrote: > John Elrick wrote: >> Yang Zhang wrote: >>> Roger Binns wrote: >>> Yang Zhang wrote: > for i in (str(row[0]) for row in conn.cursor().execute('SELECT key > FROM shelf ORDER BY ROWID')): > You are converting the key which is an integer

Re: [sqlite] Transaction isolation

John Elrick wrote: > Yang Zhang wrote: >> Roger Binns wrote: >> >>> Yang Zhang wrote: >>> for i in (str(row[0]) for row in conn.cursor().execute('SELECT key FROM shelf ORDER BY ROWID')): >>> You are converting the key which is an integer into a string for no >>>

Re: [sqlite] Transaction isolation

Yang Zhang wrote: > Roger Binns wrote: > >> Yang Zhang wrote: >> >>> for i in (str(row[0]) for row in conn.cursor().execute('SELECT key FROM >>> shelf ORDER BY ROWID')): >>> >> You are converting the key which is an integer into a string for no >> apparent reason. >> > > I

Re: [sqlite] Transaction isolation

Roger Binns wrote: > Yang Zhang wrote: >> for i in (str(row[0]) for row in conn.cursor().execute('SELECT key FROM >> shelf ORDER BY ROWID')): > > You are converting the key which is an integer into a string for no > apparent reason. I copied and pasted this code straight from my actual

Re: [sqlite] Transaction isolation

"Roger Binns" wrote in message news:4a1127e1.1040...@rogerbinns.com > If you also ask for the ROWID you will see that what is happening is a > new rowid is generated for the replaced row so that if you are > iterating over the table while modifying it then you effectively

Re: [sqlite] Transaction isolation

-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Yang Zhang wrote: > for i in (str(row[0]) for row in conn.cursor().execute('SELECT key FROM > shelf ORDER BY ROWID')): You are converting the key which is an integer into a string for no apparent reason. If you also ask for the ROWID you will see

[sqlite] Transaction isolation

Hi, for some reason the following program will loop forever: #!/usr/bin/env python import sqlite3 conn = sqlite3.connect(':memory:') conn.text_factory = bytes conn.execute('CREATE TABLE shelf (key INTEGER NOT NULL, value INTEGER NOT NULL)') for i in xrange(3): conn.execute('INSERT INTO