Hey I found this [1] maybe it can help didn't look into details yet, but even if paging not supported there we can make a patch for that ? Thoughts ?
[1] - http://empire-db.apache.org/ On Sun, Mar 25, 2012 at 5:18 PM, Mohammad Nour El-Din < [email protected]> wrote: > Hi Dan... > > OK but the use case you are proposing here still need paging, I mean > whatever the reason we wanna do paging over, whether all rows or rows that > match a certain criteria still the problem is you have a result set and you > wanna to traverse through this result set X rows at a time. > > IDK an answer for that case out of mind, but I think there might be > something that can be done with Spring or iBatis which we can use to > abstract differences between different RDBMS(s) and paging is one of them. > Thats my 2 cents. > > > On Sat, Mar 24, 2012 at 4:22 PM, Dan Haywood <[email protected] > > wrote: > >> Before answering, just a point that - if the intent is to process all rows >> in the domain model, but in batches - then the general idea of paging >> seems >> flawed to me. >> >> That is, your domain object could ask for rows 1~100, generate invoices >> for >> all, then move onto rows 101~200; however in the intervening time some >> other user could have come along and added or removed a record that could >> mess up the paging. I could see either than you either forget to generate >> an invoice, or that you end up generating an invoice more than once. >> >> I think better would be that your query is constructed to say: >> >> "give me the first 100 rows that don't yet have an invoice", and then keep >> looping through that. >> >> To do that, you'll need to add some general purpose query mechanism to the >> SQL OS; unless I'm mistaken, there doesn't seem to be one yet? >> >> Dan >> >> >> On 24 March 2012 14:54, Kevin Meyer - KMZ <[email protected]> wrote: >> >> > Hi All, >> > >> > I was doing some reading about the general problem of how to >> > implement database paging in JDBC, and since paging is not part of >> > the SQL ANSI standard, JDBC doesn't apparently have a native (API) >> > method of supporting it. >> > >> > One of the suggestions is to manually add a "datarow" column, which >> > is auto-incremented by 1 in every row. Then paging queries can be >> > spoofed via the SQL's WHERE clause. >> > >> > This assumes that rows are never deleted, which is most of my cases >> > is a reasonable one. >> > >> > Opinions? >> > >> > Otherwise, I'll have to introduce a runtime-specified paging helper >> > class that returns valid SQL for the DB being used (MySQL and >> > PostgreSQL have a completely different, and incompatible, paging >> > syntax, if memory serves). >> > >> > Regards, >> > Kevin >> > >> > >> > >> > > > > -- > Thanks > - Mohammad Nour > ---- > "Life is like riding a bicycle. To keep your balance you must keep moving" > - Albert Einstein > > -- Thanks - Mohammad Nour ---- "Life is like riding a bicycle. To keep your balance you must keep moving" - Albert Einstein
