Hello. First of all, sorry for posting three completely different questions into the same message ;)
Question #1. I was working with transactions in InnoDB (MySQL) and noticed a weird behavior. Consider we have a table: CREATE TABLE test (id INT NOT NULL PRIMARY KEY); and two transactions (from two different connections) are trying to insert a record at once: 00:01 Transaction A: BEGIN 00:02 Transaction B: BEGIN 00:03 Transaction A: INSERT INTO test VALUES (1) // works okay 00:04 Transaction B: INSERT INTO test VALUES (1) // aborts with 'duplicate key' error! why??? 00:05 Transaction A: ROLLBACK // works okay, table remains empty 00:06 Transaction B: ??? // has nothing to do because was unable to insert a record into an empty table! To put it simple, transaction A tried to insert a record but soon aborted itself via ROLLBACK. If I understand transactions principle correctly, a rolled-back transaction should act like it never happened in the first place, and other threads should not see its traces. But for some reason another transaction noticed that and refused to insert values into table. The question is: is that a correct behavior, and I should keep this in mind, or SQLite would handle this scenario different way? :/ ----- Question #2. (well, not really a question :)) Earlier in this list, I noticed several replies generally saying "using SELECT * FROM is a no-no, it's evil, you should never using that" etc. If you use fetching methods that give you associated (named) data, like mysqli_fetch_assoc() or sqlite_fetch_array(SQLITE_ASSOC), using SELECT * FROM is perfectly fine. It gives you simplified queries and allows you to separate business logic (i.e. code) from presentation layer (i.e. templates), because your logic don't have to worry about what columns are required for templates, and what not. Even if your DB schema is modified (row order changes, new rows added), your code still works because you use something like $row["id"] or $row->id, not $row[5] (which I reckon somewhat unclear). ----- Question #3. Is anyone still interested in SQLite Documentation in Windows HTML Help format I kept posting here in the past? I can continue posting links to newer .CHM versions here if you like :) Regards, Serge _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
