MongoDB first steps

Simple commands you should know!

db.createUser({
  user: "admin",
  pwd: "admin",
  roles: ["readWrite","dbAdmin"]
});

db.createCollection('customers');

show collections

db.customers.insert({first_name: "Ivan", last_name: "Ivanov"});

db.customers.find();

db.customers.insert([
  {first_name: "Ivan1", last_name: "Ivanov1"},
  {first_name: "Ivan2", last_name: "Ivanov2"},
  {first_name: "Ivan3", last_name: "Ivanov3", gender:"male"},
]);

db.customers.find().pretty();

//Update only the first match for the key and replace all the values (if not set will remove the old one)
db.customers.update({first_name: "Ivan2"}, {last_name: "222"});

//$set will keep the previous values and add the new one
db.customers.update({first_name: "Ivan2"}, {$set:{age: 45}});

//will increment with 5 the age value
db.customers.update({first_name: "Ivan2"}, {$inc:{age: 5}});

db.customers.update({first_name: "Ivan2"}, {$unset:{age: 1}});

//if not found, insert it
db.customers.update(
  {first_name: "Mariyka"}, 
  {first_name: "Mariyka", last_name: "Mariykova", gender:"female"},
  {upsert: true}
);

//rename field
db.customers.update({first_name: "Ivan2"}, {$rename:{"gender":"sex"}});

db.customers.remove({last_name: "222"});

db.customers.remove({last_name: "222"},{justOne:true});

db.customers.find({first_name: "Ivan"});

db.customers.find({$or:[{first_name: "Ivan"},{first_name: "Mariyka"}]});

//greater than ($gt)
db.customers.find({age:{$gt:40}}).pretty();

db.customers.find({"address.city":"Varna"}).pretty();

db.customers.find().sort({last_name:1}).pretty();

db.customers.find({gender:"male"}).count();

db.customers.find().limit(2);

db.customers.find().forEach(function(doc){print("Customer name: "+doc.first_name)});