sql - Unique sort order for postgres pagination -

-

while trying implement pagination server side in postgres, came across point while using limit , offset keywords have provide order clause on unique column primary key.

in case using uuid generation pkeys can't rely on sequential order of increasing keys. order pkey desc - might not result in newer rows on top always. resorted using created date column - timestamp column should unique.

but question comes if ui client wants sort other column? in event might not unique column resort order user_column, created_dt desc maintain predictable results postgres pagination.

is right approach? not sure if going right way. please advise.

i talked exact problem on old blog post (in context of using orm):

one last note using sorting , paging in conjunction. query implements paging can have odd results if order clause not include field represents empirical sequence in data; sort order not guaranteed beyond explicitly specified in order clause in (maybe all) database engines. example: if have 100 orders occurred on exact same date, , ask first page of data sorted date, ask second page of data sorted same way, entirely possible of data duplicated across both pages. depending on query , distribution of data “sortable,” can practice include unique field (like primary key) final field in sort clause if implementing paging.

http://psandler.wordpress.com/2009/11/20/dynamic-search-objects-part-5sorting/


Comments

Post a Comment

Popular posts from this blog

ios - UICollectionView Self Sizing Cells with Auto Layout -

-
Image
i'm trying self sizing uicollectionviewcells working auto layout, can't seem cells size content. i'm having trouble understanding how cell's size updated contents of what's inside cell's contentview. here's setup i've tried: custom uicollectionviewcell uitextview in contentview. scrolling uitextview disabled. the contentview's horizontal constraint is: "h:|[_textview(320)]", i.e. uitextview pinned left of cell explicit width of 320. the contentview's vertical constraint is: "v:|-0-[_textview]", i.e. uitextview pinned top of cell. the uitextview has height constraint set constant uitextview reports fit text. here's looks cell background set red, , uitextview background set blue: i put project i've been playing on github here . updated ios 9 after seeing github solution break under ios 9 got time investigate issue fully. have updated repo include several examples of different configurations s...
Read more

DOM Manipulation in Wordpress (and elsewhere) using php -

-
DOM Manipulation in Wordpress (and elsewhere) using php - i'm quite new dom manipulation world , head start in order avoid mutual errors. i looking efficient way manipulate content generated wordpress using php. @ moment using simple html dom seems work fine. found domdocument , few others , helpfull if cleared out 1 faster, improve or @ to the lowest degree generate less errors in case of bad markup. also on side can explain syntax (instead of $html @$html) thank much php wordpress domdocument simple-html-dom
Read more

asp.net - Passing parameter to telerik popup -

-
is there way pass parameter telerik similar window.showmodaldialog the way call window.showmodaldialog : window.showmodaldialog(pagename, myargs, 'status:no;dialoghide=true;help:no') myargs parameter passing popup try likes , <script type="text/javascript"> function openradwin(myargs) { radopen("yourpagename.aspx?parameter=" + myargs , "radwindow1"); } </script> <telerik:radwindowmanager id="radwindowmanager1" runat="server" enableshadow="true" visiblestatusbar="false"> <windows> <telerik:radwindow id="radwindow1" runat="server" showcontentduringload="false" width="400px" height="400px" title="telerik radwindow" behaviors="default"> </telerik:radwindow> </windows> </telerik:radwindowmanager> and , @ page_load of...
Read more