On Sun, 18 May 2014 19:15:18 +0200 RSmith <rsm...@rsweb.co.za> wrote:
> > As Igor says, http://sqlite.org/c3ref/prepare.html would be > > appropriate. However, a database connection is required for this. > > But of course.... What kind of syntactical correctness can you hope > to check without a connection? You could hope for the kind of syntactical correctness that conforms to the rules of the syntax. No schema infomation is required for that. select A from T where W = 'foo'; is valid syntax. It might not execute correctly, expecially if there's no table T with columns A and W, but that's not a syntax issue. Would a function that checks the syntax independent of schema be useful? That depends on how it's defined. As things stand, SQLite might be able to identify simple errors, sqlite> select 1a from T; Error: unrecognized token: "1a" That message is returned (with a connection, of course) from a database with no table T. It's a fine message, no objection here. But I'm having difficulty imagining how I might take advantage of it as a programmer. What's the difference between check-then-execute and execute, if the error is the same? I can easily imagine uses for a generalized SQLite parser, one that returned an abstract syntax tree. A program might use such a thing for all sorts of "server-side" functionality, for example to process a string provided to a virtual table function. But that's a very different sort of project. It wouldn't be easy to do in SQLite because AIUI the byte-code program produced by the prepare functions is concrete, comprising operations and references to actual database objects. --jkl _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
