mongodb - How do query among many collections then write result to corresponding collection -


if want query users' age > 18,

and export result corresponding collection,

how rewriteing following script?

the following psuedo code 

source_collections = ["user_1", "user_2", ..., "user_999"] output_collections = ["result_1", "result_2", ..., "result_999"] pipeline = [     {         "$match":{"age": > 18}     }     { "$out" : output_collections } ] cur = db[source_collections].runcommand('aggregate',     {pipeline: pipeline,allowdiskuse: true})

the script you're looking like:

var prefix_source = 'user_'; var prefix_output = 'result_'; var source_collections = []; var output_collections = []; var numcollections = 999;  (var = 1; <= numcollections; i++) {     source_collections.push(prefix_source + i);     output_collections.push(prefix_output + i); }  var pipeline = [{'$match': {age: {'$gt': 18}}}, {'$out': ''}];  (var currentcollection = 0; currentcollection < source_collections.length; currentcollection++) {     pipeline[pipeline.length - 1]['$out'] = output_collections[currentcollection];     var cur = db[source_collections[currentcollection]].runcommand('aggregate', {pipeline: pipeline,allowdiskuse: true}); }

and while you're @ it, var cur = ... line simplified to

db[source_collections[currentcollection]].aggregate(pipeline, {allowdiskuse: true});

note: i've added piece generates arrays you, i'm sure you're not looking write them hand :d


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