steamonimo/mongodb_queries.md

## mongodb_queries.md

      
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              mongodb_queries.md
            
          
    MongoDB: queries

Find with regular expression

db.getCollection('foo').find({"field": /.*test.*/})

Update or create field in all documents

db.getCollection('foo').updateMany({}, {$set: {field: value}})

Remove field in all documents

db.getCollection('foo').updateMany({}, {$unset: {field:1}});

Set field to value of another field in all documents

db.getCollection('foo').find({}).forEach(
    function (elem) {
        db.getCollection('foo').update(
            {
                _id: elem._id
            },
            {
                $set: {
                    field1: elem.field2
                }
            }
        );
    }
);

Update text field with javascript in all documents

db.getCollection("foo").find({}).forEach(function(elem,i) {
    elem.field1 = elem.field1.replace("FOO ","");
    db.getCollection("foo").save(elem);
});