| MongoDb | mySQL | Description |
|---|---|---|
| show dbs | SHOW DATABASES; | Print a list of databases |
| use <db> | USE <database name>; | Switch to named DB. In MongoDB this will also create a new database |
| show collections | SHOW TABLES; | Print a list of all collections / tables for current database |
| db.socks.find() | SELECT * FROM socks | Get all the documents/rows from the socks collection/table |
| db.socks.find( { _id: 10 } ) | SELECT * FROM socks WHERE id = 10; | Finds documents / rows with _id/id is equal to 10 (NB MongoDB _ID note below) |
| db.socks.find( { size: { $gt: 10, $lt: 14 } } ); | SELECT * FROM socks WHERE size > 10 AND size >14 | Get all documents/rows where the size is greater than 10 and less than 14 |
| db.socks.insertOne( { size: 8, qty: 15, colour: red } ); | INSERT INTO socks (‘size’, ‘qty’, ‘colour’) VALUES (8, 15, ‘red’); | Adds a new document/row to the collection/table |
MongoDB _id :ObjectIds are small, likely unique, fast to generate, and ordered. ObjectId values consists of 12-bytes, where the first four bytes are a timestamp that reflect the ObjectId’s creation