There is also the case of dynamically generated sql statements based on user selection... being syntax or not, I would never want half job done. Thia is the purpose of transactions: or all or nothing... Tom Lane <tgl@xxxxxxxxxxxxx> escreveu: >Rafal Pietrak <rafal@xxxxxxxxxxxxxxxxxx> writes: >> The point is, that SQL syntax errors are so obviusly different from >> execution errors, that noting this distinction should not raise any >> ambiguity. > >I beg to disagree. Typos can manifest themselves as execution errors >just as well as syntax errors. > >You are probably thinking that we could behave differently if the error >was detected by the lexer, or perhaps the lexer + grammar, rather than >later on. But those boundaries are purely implementation artifacts, >and the division of labor isn't always obvious, especially to people not >steeped in the innards of PG. Users are going to be confused (and >unhappy) if some errors roll back their transaction while other >not-obviously-different ones don't. > >As an example, suppose you fat-finger '-' for '=' in UPDATE: > > UPDATE tab SET col - 42 WHERE ... > >This is going to draw a grammar error. But make the same mistake >a few tokens later: > > UPDATE tab SET col = 42 WHERE key - 42; > >and now you will get a pretty late-stage parse analysis failure, >since it'll bleat that the argument of WHERE isn't boolean. Users >are definitely not going to understand why the former doesn't kill >their transaction but the latter does. Or, if we solve that problem >by saying that no parse-analysis failure kills the transaction, >where does that stop? The boundaries between parse analysis, planning, >and execution are even squishier and more arbitrary (from a naive user's >standpoint) than the ones earlier in the process. > > regards, tom lane > >-- >Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) >To make changes to your subscription: >http://www.postgresql.org/mailpref/pgsql-general > -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
