This chapter follows Vector search and embeddings in MongoDB. For narrative context, start with A short history of MongoDB.
mongosh
| Command | Purpose |
|---|---|
show dbs |
List databases |
use mydb |
Switch database context |
show collections |
List collections |
db.collection.find().limit(5) |
Sample query |
db.collection.getIndexes() |
List indexes |
db.runCommand({ ping: 1 }) |
Health check |
Query operators
| Operator | Meaning |
|---|---|
$eq, $ne |
Equal / not equal |
$gt, $gte, $lt, $lte |
Comparisons |
$in, $nin |
Array membership |
$and, $or, $nor |
Boolean logic |
$exists |
Field presence |
$regex |
Pattern match |
$text |
Text index search |
$near, $geoWithin |
Geospatial (indexed) |
Update operators
| Operator | Meaning |
|---|---|
$set, $unset |
Set or remove fields |
$inc |
Numeric increment |
$push, $pull, $addToSet |
Array updates |
$rename |
Rename field |
$currentDate |
Set date fields |
Aggregation stages (common)
| Stage | Role |
|---|---|
$match |
Filter |
$project |
Shape fields |
$group |
Aggregate |
$sort, $limit, $skip |
Order / slice |
$lookup |
Join |
$unwind |
Expand arrays |
$facet |
Parallel pipelines |
$merge / $out |
Persist results |
$search |
Atlas Search |
$vectorSearch |
Vector Search |
Index types
| Index | Use |
|---|---|
| Single / compound | Equality, sort, range |
| Multikey | Array fields |
| Unique | Enforce uniqueness |
| Partial | Index subset of docs |
| TTL | Expire documents |
2dsphere |
GeoJSON |
| Text | $text queries |
Node.js driver (mongodb package)
| Task | API |
|---|---|
| Connect | new MongoClient(uri).connect() |
| Insert | collection.insertOne, insertMany |
| Find | find, findOne |
| Update | updateOne, updateMany, replaceOne, findOneAndUpdate |
| Delete | deleteOne, deleteMany |
| Batch writes | bulkWrite |
| Aggregate | collection.aggregate(pipeline) |
| Index | createIndex, createIndexes |
| Transaction | session.withTransaction(fn) |
Next: MongoDB glossary.