The agent implements MongoDB NoSQL database solutions with document modeling, aggregation pipelines, and Mongoose ODM. Use when building document-based applications, designing schemas, writing aggregations, or implementing NoSQL patterns.
// Schema with Mongoose
import mongoose, { Schema, Document } from 'mongoose';
interface IUser extends Document {
email: string;
profile: { firstName: string; lastName: string };
createdAt: Date;
}
const userSchema = new Schema<IUser>({
email: { type: String, required: true, unique: true, lowercase: true },
profile: {
firstName: { type: String, required: true },
lastName: { type: String, required: true },
},
}, { timestamps: true });
userSchema.index({ email: 1 });
export const User = mongoose.model<IUser>('User', userSchema);
| Feature | Description | Guide |
|---|---|---|
| Document Schema | Type-safe schema design with Mongoose | Embed related data, use references for large collections |
| CRUD Operations | Create, read, update, delete with type safety | Use findById, , , |
findOneupdateOnedeleteOne| Aggregation Pipelines | Complex data transformations and analytics | Chain $match, $group, $lookup, $project stages |
| Indexing | Query optimization with proper indexes | Create compound indexes matching query patterns |
| Transactions | Multi-document ACID operations | Use sessions for operations requiring atomicity |
| Change Streams | Real-time data change notifications | Watch collections for inserts, updates, deletes |
async findPaginated(filter: FilterQuery<IUser>, page = 1, limit = 20) {
const [data, total] = await Promise.all([
User.find(filter).sort({ createdAt: -1 }).skip((page - 1) * limit).limit(limit),
User.countDocuments(filter),
]);
return { data, pagination: { page, limit, total, totalPages: Math.ceil(total / limit) } };
}
const stats = await Order.aggregate([
{ $match: { status: 'completed', createdAt: { $gte: startDate } } },
{ $group: { _id: '$userId', total: { $sum: '$amount' }, count: { $sum: 1 } } },
{ $sort: { total: -1 } },
{ $limit: 10 },
]);
const session = await mongoose.startSession();
try {
session.startTransaction();
await Product.updateOne({ _id: productId }, { $inc: { stock: -quantity } }, { session });
const order = await Order.create([{ userId, items, total }], { session });
await session.commitTransaction();
return order[0];
} catch (error) {
await session.abortTransaction();
throw error;
} finally {
session.endSession();
}
| Do | Avoid |
|---|---|
| Design schemas based on query patterns | Embedding large arrays in documents |
| Create indexes for frequently queried fields | Using $where or mapReduce in production |
Use lean() for read-only queries | Skipping validation on writes |
| Implement pagination for large datasets | Storing large files directly (use GridFS) |
| Set connection pool size appropriately | Hardcoding connection strings |
| Use transactions for multi-document ops | Ignoring index usage in explain plans |
| Add TTL indexes for expiring data | Creating too many indexes (write overhead) |