On Mon, 25 Nov 2013 19:44:15 +0100 Luuk <luu...@gmail.com> wrote: > On 25-11-2013 13:41, Simon Slavin wrote: > > I'm wondering whether there's an argument that it should be > > evaluated just once for a transaction. > > I'm still thinking about this question, > > i can think of some benefits if its evaluated just once per > transaction. > > but i hope anyone has some examples why its better to evalutate it > once per statement.
The easy answer is: that's how SQL is defined. A more complicated answer is that, inside a user-defined transaction, you have control over the meaning of "now". You can insert "now" into a table and re-use it as often as you like, without fear of it being changed by another process. If, on the other hand, you'd like to execute several statements in a transaction, you might also like to know when "now" is for each one. The per-statement definition of "now" supports that use. There's actually nothing special about "now". Other functions, e.g. changes(), may vary between statements in a transaction. (It happens SQLite doesn't have many such.) You really just want to preserve the function's defintion as "returns correct output each time it's called". HTH. --jkl _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
