Write Operations

Agenda Create Collection Insert Update Remove

Create Collection db.createCollection(“COLLECTION_NAME”) You can also insert into a collection that doesn’t exist yet. This will create a new collection db.people.insertOne( { user_id: "abc123", age: 55, status: "A" } )

Insert MongoDB db.collection.insert() Inserts a new doc with the age, name, status, and _id fields

Insert Mysql

Insert Adding a doc without an _id field is ok. MongoDB will auto generate a unique id. If you specify the _id field, it must be unique to the current collection.

Insert One db.collection.insertOne() inserts a single document into a collection db.inventory.insertOne( { item: "canvas", qty: 100, tags: ["cotton"], size: { h: 28, w: 35.5, uom: "cm" } } ) Query the database to find the document that you just inserted: db.inventory.find( { item: "canvas" } )

Insert Multiple db.collection.insertMany() inserts multiple documents. Pass an array of docs to insertMany db.inventory.insertMany([ { item: "journal", qty: 25, tags: ["blank", "red"], size: { h: 14, w: 21, uom: "cm" } }, { item: "mat", qty: 85, tags: ["gray"], size: { h: 27.9, w: 35.5, uom: "cm" } }, { item: "mousepad", qty: 25, tags: ["gel", "blue"], size: { h: 19, w: 22.85, uom: "cm" } } ])

Update MongoDB Updates a document that matches the criteria Updates are atomic within a single document

Update Mysql

Update One db.inventory.updateOne( { item: "paper" }, { $set: { "size.uom": "cm", status: "P" } } )

Update Many db.books.updateMany( { stock: { $lte: 10 } }, { $set: { reorder: true } }, { multi: true } )

Upsert An update that, if the doc exists, it will do an update If the doc does not exist, it will do an insert db.people.update( { name: "Andy" }, { name: "Andy", rating: 1, score: 1 }, { upsert: true } )

Update Operators Lots of different update operators Only concerned with $set db.products.update( { _id: 100 }, { $set: { "details.make": "zzz" } } ) https://docs.mongodb.com/manual/reference/operator/update/

Remove MongoDB Deletes doc from collection Accepts a query criteria to determine which docs to remove

Remove Mysql