Update offspring in nested tree mongoDB, node.js -

-

is there way update nested documents id or other field?

i use "full tree in single document" , don't know beforehand how deep nesting can go. need update, example, answer {id:'104'}. can via 'dot notation', since don't know level (depth) of nesting can't predict how long 'comment.answers.answers....answers.' can go.

is there way directly find , update id:'104', or still need pass kind of depth mark?

{  title:'some title',  comment:      {         id:'101'         author:'joe',         text:'some comment',         answers:         [             {               id:'102'               author:'joe',               text:'first answer comment',               answers:                     [                        {                            id:'103'                            author:'done',                            text:'first answer first answer comment',                            answers:[]                        },                        {                            id:'104'                            author:'bob',                            text:'second answer first answer comment',                            answers:[]                        }                      ]              },              {             },              {             },         ]      } }

i use the node.js mongodb driver

in short there's no way query of sort. there few options:

you can create query long $or statement, specifying each of possible nested locations document: 

{ comment.id: 103, $or [                         { comment.answers.id: 103 },                          { comment.answers.answers.id: 103 },                         { comment.answers.answers.answers.id: 103 }                         ]  }

for more information $or operator see docs.

in truth, better , more sustainable solution use different schema, comments , answers stored in flat array , store information relationships between comments in comments.parent field. example:

 { comment: [            { id: 1 }            { id: 2, parent: 1 }           ] }

for additional options , more in depth discussion of possible ways of modeling comment hierarchies, view storing comments use case in mongodb documentation.

there number of strategies in trees in mongodb might want consider.


Comments

Post a Comment

Popular posts from this blog

c# - SVN Error : "svnadmin: E205000: Too many arguments" -

-
i trying reposotries using c# code process svncommand = null; var psi = new processstartinfo("svnadmin"); psi.redirectstandardoutput = true; psi.redirectstandarderror = true; psi.useshellexecute = false; psi.arguments= @"dump c:\repositories\myrepo > c:\temp\myrepodumpfile.dump"; using (svncommand = process.start(psi)) { var myoutput = svncommand.standardoutput; var myerror = svncommand.standarderror; debug.write("output :" + environment.newline + environment.newline + myoutput.readtoend() + environment.newline + "error :" + environment.newline + environment.newline + myerror.readtoend()); svncommand.close(); } when use dump command commandline svnadmin dump c:\repositories\myrepo > c:\temp\myrepodumpfile.dump it works fine when try ...
Read more

c# - Copy ObservableCollection to another ObservableCollection -

-
how copy observablecollection item observablecollection without reference of first collection? here observablecollection item value changes affecting both collections. code private observablecollection<ratemodel> _allmetalrate = new observablecollection<ratemodel>(); private observablecollection<ratemodel> _metalrateondate = new observablecollection<ratemodel>(); public observablecollection<ratemodel> allmetalrate { { return this._allmetalrate; } set { this._allmetalrate = value; notifypropertychanged("metalrate"); } } public observablecollection<ratemodel> metalrateondate { { return this._metalrateondate; } set { this._metalrateondate = value; notifypropertychanged("metalrateondate"); } } foreach (var item in metalrateondate) allmetalrate.add(item); what causing , how can solve it? you need clone object referenced item before it's a...
Read more

All overlapping substrings matching a java regex -

-
is there api method returns (possibly overlapping) substrings match regular expression? for example, have text string: string t = 04/31 412-555-1235; , , have pattern: pattern p = new pattern("\\d\\d+"); matches strings of 2 or more characters. the matches are: 04, 31, 412, 555, 1235. how overlapping matches? i want code return: 04, 31, 41, 412, 12, 55, 555, 55, 12, 123, 1235, 23, 235, 35. theoretically should possible -- there obvious o(n^2) algorithm enumerates , checks substrings against pattern. edit rather enumerating substrings, safer use region(int start, int end) method in matcher . checking pattern against separate, extracted substring might change result of match (e.g. if there non-capturing group or word boundary check @ start/end of pattern). edit 2 actually, it's unclear whether region() expect zero-width matches. specification vague, , experiments yield disappointing results. for example: string line = "xx90xx"; strin...
Read more