The problem with that approach is that you end up with a lot of code like: if (!dbBegin(con)) stop(dbGetException()) ... if (!dbExecute(con, sql)) stop(dbGetException()) ... if (!dbCommit(con)) stop(dbGetException())
where the developer is responsible for always checking that the operation succeeded. If you throw an error, then the code is simpler: dbBegin(con) ... dbExecute(con, sql) ... dbCommit(con) Given that we're using a language with exceptions, it seems better to use them, rather than adopting the standard C error handling mechanism. Hadley On Thu, Sep 4, 2014 at 9:45 AM, Peter Meißner <peter.meiss...@uni-konstanz.de> wrote: > IMHO > > the general approach should be: > > - as long as R does deliver the the queries to the DB and the DB does give > response there should never ever be an R error - the function did what it > should do: making sure things were delivered to DB > > - the return than should depend on what the DB said: > * 0/TRUE - no error, nothing else to say > * 1/FALSE - DB does complain somehow > * text/whatever appropriate - something was returned, ... > > - if however connection was lost during the execution of the function so it > cannot be sure delivery went as expected an error should be issued > > Best, Peter > > > > Am 04.09.2014 16:28, schrieb Denis Mukhin: > >> In ROracle we standardized on the second approach, namely always return >> TRUE, otherwise throw an error. >> >> Also since UPDATE is not the only operation that does not return any >> results (although it might with a RETURNING clause) would a more generic >> name be more appropriate here? Besides DMLs there are also DDLs. Something >> like dbExecute(), dbSubmit(), dbSend() ... >> >> Denis >> >> -----Original Message----- >> From: Hadley Wickham [mailto:had...@rstudio.com] >> Sent: Thursday, September 04, 2014 9:13 AM >> To: MacQueen, Don >> Cc: Simon Urbanek; R-sig-DB@r-project.org >> Subject: Re: [R-sig-DB] Add a "dbSendUpdate" function to DBI? >> >> A thought: should dbSendUpdate() return a boolean indicating success, or >> always return TRUE, otherwise throwing an error? >> >> Hadley >> >> On Wed, Sep 3, 2014 at 3:59 PM, MacQueen, Don <macque...@llnl.gov> wrote: >>> >>> Hadley, >>> >>> Since you mentioned DBI 0.3 in a recent email, could I make a request >>> to add a dbSendUpdate() function to DBI, like the one in RJDBC? >>> >>> require(RJDBC) >>> >>>> find('dbSendQuery') >>> >>> [1] "package:RJDBC" "package:DBI" >>> >>>> find('dbSendUpdate') >>> >>> [1] "package:RJDBC" >>> >>> And from ?dbSendUpdate >>> >>> 'dbSendQuery' and 'dbSendUpdate' submit a SQL query to the >>> database. The difference between the two is only that >>> 'dbSendUpdate' is used with DBML queries and thus doesn't return >>> any result set. >>> >>> I would find this helpful, because I could then use scripts unmodified >>> with either ROracle or RJDBC. >>> (I suppose adding it to DBI would mean that the one in RJDBC would >>> have to be modified.) >>> >>> >>> I have: >>> >>> Package Version >>> "DBI" "0.3.0" >>> >>> Package Version >>> "RJDBC" "0.2-4" >>> >>> >>> Thanks >>> -Don >>> >>> -- >>> Don MacQueen >>> Lawrence Livermore National Laboratory >>> 7000 East Ave., L-627 >>> Livermore, CA 94550 >>> 925-423-1062 >>> >> >> >> >> -- >> http://had.co.nz/ >> >> _______________________________________________ >> R-sig-DB mailing list -- R Special Interest Group R-sig-DB@r-project.org >> https://stat.ethz.ch/mailman/listinfo/r-sig-db >> >> _______________________________________________ >> R-sig-DB mailing list -- R Special Interest Group >> R-sig-DB@r-project.org >> https://stat.ethz.ch/mailman/listinfo/r-sig-db >> > > -- > Peter Meißner > Workgroup 'Comparative Parliamentary Politics' > Department of Politics and Administration > University of Konstanz > Box 216 > 78457 Konstanz > Germany > > +49 7531 88 5665 > http://www.polver.uni-konstanz.de/sieberer/home/ > > > _______________________________________________ > R-sig-DB mailing list -- R Special Interest Group > R-sig-DB@r-project.org > https://stat.ethz.ch/mailman/listinfo/r-sig-db -- http://had.co.nz/ _______________________________________________ R-sig-DB mailing list -- R Special Interest Group R-sig-DB@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-db
