MongoDB Mini User Guide
Shell Mongo :
> mongo
Once you are in terminal/command line, access the database/collection you want to use as follows:
show dbs
use <db name>
show collections
choose your collection and type the following to see all contents of that collection:
db.collectionName.find()
for a query below some samples :
db.products.find({ "_id": "apples", "qty": 5 }
db.products.find( { qty: { $gt: 25 } } )
db.students.find( { score: { $gt: 0, $lt: 2 } } )
db.bios.find( { _id: 5 } )
db.bios.find( { contribs: "UNIX" } ) >>>>>> Array elements
Check this link for more : https://docs.mongodb.com/manual/reference/method/db.collection.find/
Import / Export command in MongoDB (Unicode files)(json)
mongoimport -d comedy -c cartoons -file collections.json mongoexport -d comedy -c cartoons -o collections.json
Change collection name in mongodb
db.oldname.renameCollection("newname")
Change type fields :
// String to Integer for notice_id db.mycollection.find({notice_id : {$exists : true}}).forEach( function(obj) { obj.notice_id = new NumberInt(obj.notice_id); db.mycollection.save(obj); } );
// Integer to String for field-name db.db-name.find({field-name : {$exists : true}}).forEach( function(obj) { obj.field-name = ""+obj.field-name; db.db-name.save(obj); } );
Rename a field in mongoDB :
db.mycollection.update ( {}, { $rename : { "notice_id" : "isn" }}, false, true );
Delete a collection
db.compta.drop();
Empty a collection
db.compta.remove();
Under the Mongodb shell please import the follwing json file (test.json) listed below with :
mongoimport -d test -c compta -file d:test.json
{ “montant” : 3.95, “travel” : “Prague”, “sens” : “credit” }
{ “montant” : 6.03, “travel” : “Prague”, “sens” : “credit” }
{ “montant” : 5.53, “travel” : “New York”, “sens” : “credit” }
{ “montant” : -1.96, “travel” : “New York”, “sens” : “debit” }
{ “montant” : 3.95, “tickets” : “eurodisney”, “sens” : “credit” }
{ “montant” : 6.03, “tickets” : “asterix”, “sens” : “credit” }
Mongo Request Sum or Total aggregate :
db.compta.aggregate({$group:{ _id:"", montant: {$sum: "$montant"}} }, {$project:{ _id:0, montant: "$montant"}}); db.compta.aggregate({$group:{ _id:"$travel", montant: {$sum: "$montant"}} }, {$project:{ _id:1, montant: "$montant"}}); <br?>