what is purpose of order in mysql index -

-

i have table person in there field contact number want add indexing on contact number. in mysql purpose on ordering while indexing field.

index contact_number (contact_number asc))

right (mysql 5.7) asc/desc ignored mysql.

http://dev.mysql.com/doc/refman/5.7/en/create-index.html

an index_col_name specification can end asc or desc. these keywords permitted future extensions specifying ascending or descending index value storage. currently, parsed ignored; index values stored in ascending order.

if implemented day might useful composite indices: http://explainextended.com/2009/04/27/descending-indexes/


Comments

Post a Comment

Popular posts from this blog

Hatching array of circles in AutoCAD using c# -

-
i beginner in autocad plugins .i have created array of circle using following code. now, have hatch circles in array .how that??how hatch circles @ once? moreover, how can return hatch method , use hatch objects.sorry language.thanks in advance. [assembly: commandclass(typeof(beamsection.class1))] namespace beamsection { public class class1 { //class1 obj = new class1(); [commandmethod("beamatsupport")] public void addlightweightpolyline() { // current document , database document acdoc = application.documentmanager.mdiactivedocument; database accurdb = acdoc.database; promptpointresult ppr = acdoc.editor.getpoint("\nselect starting point "); var ucs = acdoc.editor.currentusercoordinatesystem; point3d startingpt = ppr.value.transformby(ucs); list<double> radius = new list<double>(); radius.add(0.5); ...
Read more

ios - UITEXTFIELD InputView Uipicker not working in swift -

-
hello trying pop uipickerview view programmatically when user clicks on textfield. have tried doesn't doing anything. isn't working. nothing happening when click textfield class userprofiletableviewcontroller: uitableviewcontroller,uitextfielddelegate,uipickerviewdelegate,uipickerviewdatasource { var itempicker: uipickerview! = uipickerview() @iboutlet weak var gendertxtfield: uitextfield! var gender = ["male","female"] override func viewdidload() { super.viewdidload() gendertxtfield.delegate = self itempicker!.delegate = self itempicker!.datasource = self itempicker!.backgroundcolor = uicolor.blackcolor() self.gendertxtfield.inputview = itempicker } func numberofcomponentsinpickerview(pickerview: uipickerview) -> int{ return 1 } // returns # of rows in each component.. func pickerview(pickerview: uipickerview, numberofrowsincomponent component:...
Read more