So how do you propose to have consistency and isolation if SELECT does not create an automatic transaction if no explicit transaction exists?
Consider: SELECT <some stuff> FROM <somewhere>; BEGIN; UPDATE <somewhere else> SET field = <some stuff> +1; COMMIT; If the SELECT and UPDATE statements are not part of the same transaction, there is no guarantee that <some stuff> is still valid by the time you use it in the UPDATE. Or even better: SELECT <value1> FROM <somewhere>; SELECT <value2> FROM <wherever>; How do you know that the expression <value1> + <value2> ever had that specific value (either one, or both, could have been changed between the two read operations)? -----Ursprüngliche Nachricht----- Von: sqlite-users [mailto:sqlite-users-boun...@mailinglists.sqlite.org] Im Auftrag von Kira Backes Gesendet: Montag, 12. August 2019 11:01 An: SQLite mailing list <sqlite-users@mailinglists.sqlite.org> Betreff: Re: [sqlite] [EXTERNAL] SQLITE_BUSY (SQLITE_BUSY_SNAPSHOT) due to a simple SELECT query -- Documentation needed! PS: > Another example: X starts a read transaction using BEGIN and SELECT, then Y > makes a changes to the database using UPDATE. Same goes for this example! We did not start a read transaction with BEGIN. This part says that you need to start a read transaction with BEGIN, which we did not do, and the other part says that SELECTs do *NOT* start an automatic transaction. So is this maybe even a bug in sqlite? Or the documentation is incorrect? kind regards, Kira Backes _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users ___________________________________________ Gunter Hick | Software Engineer | Scientific Games International GmbH | Klitschgasse 2-4, A-1130 Vienna | FN 157284 a, HG Wien, DVR: 0430013 | (O) +43 1 80100 - 0 May be privileged. May be confidential. Please delete if not the addressee. _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
