## Mongo DB Queries
### READ: All text that are uppercase are just placeholders and can be replaced
**show dbs** - show databases that have collections
**use DBNAME** - switch to use database or create a new database
**show collections** - show collections of the currently used database
**db** - to show currently used database
**db.dropDatabase()** - delete currently used database
**db.createCollection('COLLECTION')** - create collection
**db.COLLECTION.insert(DATA)** - insert data in collection (data must be an object)
**db.COLLECTION.insertMany(DATAS)** - insert many datas in collection (datas must be objects)
**db.COLLECTION.find()** - show all datas in collection (add a .pretty() method for a formatted result)
**db.COLLECTION.findOne(CONDITION)** - show only one data in collection (add a .pretty() method for
a formatted result)
**db.COLLECTION.find().sort({FIELD:1})** show all datas in collection based on a field in ascending or
descending (1 for ASC, -1 for DESC)
**db.COLLECTION.find(CONDITION)** - show all datas in collection based on a condition (like WHERE clause in SQL)
condition must be an object
**db.COLLECTION.find().count()** - show counts of data in collection (can also be based on a condition)
**db.COLLECTION.find().limit(LIMIT)** - show limited data in collection (can also be based on a condition)
based on the number passed in limit()
**db.COLLECTION.update(CONDITION, UPDATED_DATA)** - update all entries of a collection based on a condition
(add {upsert:true} in update() if you wanted the new data to be inserted in the collection if a condition
did not match any data)
**db.COLLECTION.update(CONDITION, { $set:{UPDATED_DATA} })** - update some entries of a collection based on a
condition (add **{upsert:true}** in update() if you wanted the new data to be inserted in the collection if a condition
did not match any data)
can also use **$inc** to increment a data and **$rename** to rename a field
**db.COLLECTION.remove(CONDITION)** - remove a data from a collection
**db.COLLECTION.createIndex(INDEX)** - create a search index
Some other operators:
** $gt and $gte ** - greater than and greater than or equal
** $lt and $lte ** - less than and less than or equal
** $search ** - search query
** $elemMatch ** - matching in multiple datas