[sqlite] read uncommitted data consistency
On 21 Feb 2015, at 9:01pm, Yuriy Stelmakh wrote: > When using read uncommitted pragma, is it possible to get a row of data > where some columns reflect state of that row at one point, while others at > another? For example when you are reading in one thread while writing in > another. No. They'll all be either one thing or the other. In other words, even with the PRAGMA set, SQLite is still transaction-safe. It uses a lock on the entire database to prevent the problem you described. Simon.
[sqlite] Sqlite3 tutorial and reference manuals?
Thanks. I doing building automation using Raspberry Pi, Arduino, and zigbee devices. I started with Python, but that is too slow, so I would like to move to C++. Dropped messages are not acceptable, and response to user actions needs to be "timely". I'll hold futher questions until after looking at the recommendations my by you kind people. On 02/21/2015 01:36 PM, Paolo Bolzoni wrote: > About SQL I like the w3c schools[1]; about sqlite how do you want to > use it? Via C interface? If so, check the website "sqlite in 5 minutes > or less"[2]. > > [1]http://www.w3schools.com/sql/ > [2]https://www.sqlite.org/quickstart.html > > On Sat, Feb 21, 2015 at 7:33 PM, russ lyttle wrote: >> I'm new to sqlite and not that experienced with SQL in general. Are >> there any good sqlite tutorials or references better than the first few >> pages returned by a google search? >> >> I have reference and tutorial books for MySql. >> >> >> ___ >> sqlite-users mailing list >> sqlite-users at mailinglists.sqlite.org >> http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users >> > ___ > sqlite-users mailing list > sqlite-users at mailinglists.sqlite.org > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users > -- next part -- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 473 bytes Desc: OpenPGP digital signature URL: <http://mailinglists.sqlite.org/cgi-bin/mailman/private/sqlite-users/attachments/20150221/752f584b/attachment.pgp>
[sqlite] Sqlite3 tutorial and reference manuals?
Thanks for the recommendation. Sorry about the multiple postings, but thunderbird was telling me it couldn't send the messages. I think I've got it fixed now. On 02/21/2015 01:48 PM, Conery John wrote: > I really like Using SQLite, by Jay Kreibich (O?Reilly and Associates). > Comprehensive coverage of SQLite plus useful information on database design. > > John Conery > >> On Feb 21, 2015, at 10:36 AM, Paolo Bolzoni > gmail.com> wrote: >> >> About SQL I like the w3c schools[1]; about sqlite how do you want to >> use it? Via C interface? If so, check the website "sqlite in 5 minutes >> or less"[2]. >> >> [1]http://www.w3schools.com/sql/ >> [2]https://www.sqlite.org/quickstart.html >> >> On Sat, Feb 21, 2015 at 7:33 PM, russ lyttle wrote: >>> I'm new to sqlite and not that experienced with SQL in general. Are >>> there any good sqlite tutorials or references better than the first few >>> pages returned by a google search? >>> >>> I have reference and tutorial books for MySql. >>> >>> >>> ___ >>> sqlite-users mailing list >>> sqlite-users at mailinglists.sqlite.org >>> http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users >>> >> ___ >> sqlite-users mailing list >> sqlite-users at mailinglists.sqlite.org >> http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users > > ___ > sqlite-users mailing list > sqlite-users at mailinglists.sqlite.org > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users > -- next part -- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 473 bytes Desc: OpenPGP digital signature URL: <http://mailinglists.sqlite.org/cgi-bin/mailman/private/sqlite-users/attachments/20150221/5963113a/attachment.pgp>
[sqlite] read uncommitted data consistency
When using read uncommitted pragma, is it possible to get a row of data where some columns reflect state of that row at one point, while others at another? For example when you are reading in one thread while writing in another. Thank you!
[sqlite] Sqlite3 tutorial and reference manuals?
About SQL I like the w3c schools[1]; about sqlite how do you want to use it? Via C interface? If so, check the website "sqlite in 5 minutes or less"[2]. [1]http://www.w3schools.com/sql/ [2]https://www.sqlite.org/quickstart.html On Sat, Feb 21, 2015 at 7:33 PM, russ lyttle wrote: > I'm new to sqlite and not that experienced with SQL in general. Are > there any good sqlite tutorials or references better than the first few > pages returned by a google search? > > I have reference and tutorial books for MySql. > > > ___ > sqlite-users mailing list > sqlite-users at mailinglists.sqlite.org > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users >
[sqlite] read uncommitted data consistency
On Feb 21, 2015, at 5:36 PM, Simon Slavin wrote: > > On 21 Feb 2015, at 9:01pm, Yuriy Stelmakh wrote: > >> When using read uncommitted pragma, is it possible to get a row of data >> where some columns reflect state of that row at one point, while others at >> another? For example when you are reading in one thread while writing in >> another. > > No. They'll all be either one thing or the other. In other words, even with > the PRAGMA set, SQLite is still transaction-safe. It uses a lock on the > entire database to prevent the problem you described. > No, not with columns, but it is possible with rows, depending on how the two treads are interacting. SQLite rows are essentially self-contained, so any time a row is updated it is updated as a complete unit. This is not true of rows within a table, however. Understand that READ UNCOMMITTED only applies to connections within the same process that are also using a shared cache (sqlite3_enable_shared_cache()). If, in the situation you describe, the threads are using different connections that are NOT using a shared cache, then the writer thread will ?see? any updates it has already made within the uncommitted transaction, while another reader thread (using a different connection) will not? it will see the data as it existed when the transaction was started. This has nothing to do with READ UNCOMMITTED, however, that?s how it always works when not using a shared cache (or when not using the same connection for reads and writes). Basically the connection context that created the transaction will see the actions it has performed, while all other connections will not see the changes until the transaction is committed (which, of course, is the whole point of transactions). -j -- Jay A. Kreibich < J A Y @ K R E I B I.C H > "Intelligence is like underwear: it is important that you have it, but showing it to the wrong people has the tendency to make them feel uncomfortable." -- Angela Johnson
[sqlite] Reference material for SQLITE3
On 2/21/2015 1:43 PM, russ lyttle wrote: > I'm new to sqlite and would like some intermediate to advanced tutorial > and reference material. http://sqlite.org/docs.html -- Igor Tandetnik
[sqlite] Reference material for SQLITE3
I'm new to sqlite and would like some intermediate to advanced tutorial and reference material. Google didn't return much useful beyond elementary level. -- next part -- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 473 bytes Desc: OpenPGP digital signature URL: <http://mailinglists.sqlite.org/cgi-bin/mailman/private/sqlite-users/attachments/20150221/33762c89/attachment.pgp>
[sqlite] Email Removal
Please remove me from all of your email lists. Thanks
[sqlite] sqlite tutorials and reference manuals?
I'm new to sqlite. Can anyone recommend online or hardcopy tutorials and reference manuals for sqlite? Google search hasn't returned much useful. -- next part -- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 473 bytes Desc: OpenPGP digital signature URL: <http://mailinglists.sqlite.org/cgi-bin/mailman/private/sqlite-users/attachments/20150221/ec3c1906/attachment.pgp>
[sqlite] Sqlite3 tutorial and reference manuals?
I'm new to sqlite and not that experienced with SQL in general. Are there any good sqlite tutorials or references better than the first few pages returned by a google search? I have reference and tutorial books for MySql. -- next part -- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 473 bytes Desc: OpenPGP digital signature URL: <http://mailinglists.sqlite.org/cgi-bin/mailman/private/sqlite-users/attachments/20150221/9356a802/attachment.pgp>
[sqlite] Sqlite3 tutorial and reference manuals?
I really like Using SQLite, by Jay Kreibich (O?Reilly and Associates). Comprehensive coverage of SQLite plus useful information on database design. John Conery > On Feb 21, 2015, at 10:36 AM, Paolo Bolzoni gmail.com> wrote: > > About SQL I like the w3c schools[1]; about sqlite how do you want to > use it? Via C interface? If so, check the website "sqlite in 5 minutes > or less"[2]. > > [1]http://www.w3schools.com/sql/ > [2]https://www.sqlite.org/quickstart.html > > On Sat, Feb 21, 2015 at 7:33 PM, russ lyttle wrote: >> I'm new to sqlite and not that experienced with SQL in general. Are >> there any good sqlite tutorials or references better than the first few >> pages returned by a google search? >> >> I have reference and tutorial books for MySql. >> >> >> ___ >> sqlite-users mailing list >> sqlite-users at mailinglists.sqlite.org >> http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users >> > ___ > sqlite-users mailing list > sqlite-users at mailinglists.sqlite.org > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
