MongoDB Collection Operations: Creation, Deletion, and Data Insertion
MongoDB collections are analogous to tables in relational databases, storing flexible documents (structured like JSON) where different documents can have distinct fields, with no fixed schema. There are two methods to create a collection: explicitly using `db.createCollection(collectionName)` (supporting attributes like `capped` for fixed size) or implicitly when data is first inserted. To delete a collection, use `db.collectionName.drop()`, which returns `true` on success. Deleted data is permanently lost, so caution is advised. Data insertion is done via `insertOne()` (single document) and `insertMany()` (multiple documents). Documents are key-value pairs, with a unique `_id` automatically generated (customizable but default is recommended). **Notes**: Collection names are case-sensitive and must not contain special characters beyond valid symbols; data types must follow standards (e.g., use `new Date()` for dates); deletions are irreversible, so backup before operations is strongly recommended. (Word count: 198)
Read MoreMongoDB Shell Introduction: Simple Database Operations via Command Line
The MongoDB Shell is a JavaScript-based interactive command-line tool for directly operating MongoDB databases, suitable for beginners. After installing MongoDB, simply type "mongo" in the terminal to start the Shell. Basic operations include: using `db` to view the current database, `use database_name` to switch (creates the database automatically if it doesn’t exist when inserting data); for remote connections, use `mongo --host remote_IP --port port` (default port is 27017). Data operations: Insert a single document with `insertOne({...})` (creates the collection automatically); query with `find()`/`findOne()` (use `find().pretty()` for formatted output); update with `updateOne()` (modify fields using `$set`) or `updateMany()` (increment with `$inc`); delete with `deleteOne()` or `deleteMany()`. Management operations: `show dbs` lists databases; `db.dropDatabase()` deletes the current database; `db.collection_name.drop()` deletes a collection. Advanced tips include `countDocuments()` for counting and `limit()` for restricting results. It is recommended to practice more and consult the official documentation for complex operations.
Read MoreMaster MongoDB CRUD Operations: 4 Essential Basic Operations for Beginners
This article introduces the basic CRUD operations of MongoDB. MongoDB is a document - oriented database, where data is stored in BSON format and documents are placed in collections without a fixed table structure. Before performing operations, the service needs to be started. Then, enter the Shell through `mongo`, use `use` to switch databases, and select a collection with `db.collection name`. **Create**: To insert a single document, use `insertOne()` (e.g., inserting a user document). For multiple documents, use `insertMany()` (e.g., inserting multiple users). The return result contains the document ID and operation confirmation information. **Read**: The core is `find()`, which supports conditional filtering (e.g., `age: { $gt: 20 }`), field projection (`{name:1, _id:0}`), sorting (`sort({age:1})`), and limiting the number of results (`limit(2)`). **Update**: `updateOne()` is used to update a single document, and `updateMany()` is used to update multiple documents. Use `$set` to overwrite fields (e.g., changing the name) and `$inc` to increment fields (e.g., increasing the age by 1). **Delete**: `deleteOne()` is for deleting a single document, `deleteMany()` is for deleting multiple documents, and `deleteMany({})` is used to clear the collection. The operation needs to
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