Mongodb choose from different databases
I have about 200 mongodb databases. Each database has a collection called "Group" and this collection has a "meldingId" field.
Is it possible to make one mongodb query that finds all values in different databases.
(I was able to select bij databases going through databases using selectDB ($ database_name))
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In Mongo shell, this can be done using the method to switch to admin database and get a list of 200 databases by running admin command . Go through the list of databases and use again to switch between databases, query collection for values . Something like that: db.getSiblingDB()
db.runCommand({ "listDatabases": 1 })
db.getSiblingDB()
Group
meldingId
// Switch to admin database and get list of databases.
db = db.getSiblingDB("admin");
dbs = db.runCommand({ "listDatabases": 1 }).databases;
// Iterate through each database.
dbs.forEach(function(database) {
db = db.getSiblingDB(database.name);
// Get the Group collection
collection = db.getCollection("Group");
// Iterate through all documents in collection.
/*
collection.find().forEach(function(doc) {
// Print the meldingId field.
print(doc.meldingId);
});
*/
var meldingIds = collection.distinct('meldingId');
print(meldingIds);
});
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