125 lines
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5.9 KiB
Markdown
125 lines
No EOL
5.9 KiB
Markdown
---
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website: https://www.mongodb.com
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obj: application
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---
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# MongoDB
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MongoDB is a popular NoSQL database that is document-oriented and designed for scalability and flexibility. You can work with MongoDB in a GUI with [MongoDB Compass](MongoDB%20Compass.md).
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## Docker-Compose
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```yml
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version: '3'
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services:
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mongo:
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image: mongo
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restart: always
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environment:
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MONGO_INITDB_ROOT_USERNAME: root
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MONGO_INITDB_ROOT_PASSWORD: password
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volumes:
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- ./db:/data/db
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ports:
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- "27017:27017"
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```
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## Usage
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### **Connecting to MongoDB**
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To connect to MongoDB using the `mongo` shell:
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`mongo mongodb://<username>:<password>@<hostname>:<port>/<database>`
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Replace `<username>`, `<password>`, `<hostname>`, `<port>`, and `<database>` with your own values.
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### **Working with Databases**
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To create a new database: `use <database>`
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To show a list of all databases: `show dbs`
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To switch to a different database: `use <database>`
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To drop a database: `use <database>; db.dropDatabase()`
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### **Working with Collections**
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To create a new collection: `db.createCollection("<collection>")`
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To show a list of all collections in the current database: `show collections`
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To drop a collection: `db.<collection>.drop()`
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### **Inserting Data**
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To insert a single document: `db.<collection>.insertOne(<document>)`
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To insert multiple documents: `db.<collection>.insertMany([<document1>, <document2>, ...])`
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### **Querying Data**
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To find all documents in a collection: `db.<collection>.find()`
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To find documents that match a specific condition: `db.<collection>.find(<query>)`
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To limit the number of documents returned: `db.<collection>.find().limit(<limit>)`
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To sort documents by a field: `db.<collection>.find().sort({<field>: <1 or -1>})`
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To count the number of documents: `db.<collection>.count()`
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### **Updating Data**
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To update a single document: `db.<collection>.updateOne(<filter>, <update>)`
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To update multiple documents: `db.<collection>.updateMany(<filter>, <update>)`
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To replace a document: `db.<collection>.replaceOne(<filter>, <replacement>)`
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### **Deleting Data**
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To delete a single document: `db.<collection>.deleteOne(<filter>)`
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To delete multiple documents: `db.<collection>.deleteMany(<filter>)`
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To delete all documents in a collection: `db.<collection>.deleteMany({})`
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### Filters
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Usage:
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```json
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{ "field": { "$mod": "value" } }
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```
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- `$eq`: The `$eq` operator matches documents where the value of a field equals a specified value.
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- `$ne`: The `$ne` operator matches documents where the value of a field is not equal to a specified value.
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- `$gt`: The `$gt` operator matches documents where the value of a field is greater than a specified value.
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- `$gte`: The `$gte` operator matches documents where the value of a field is greater than or equal to a specified value.
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- `$lt`: The `$lt` operator matches documents where the value of a field is less than a specified value.
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- `$lte`: The `$lte` operator matches documents where the value of a field is less than or equal to a specified value.
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- `$in`: The `$in` operator matches documents where the value of a field equals any value in a specified array.
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- `$nin`: The `$nin` operator matches documents where the value of a field does not equal any value in a specified array.
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- `$and`: The `$and` operator performs a logical AND operation on an array of two or more expressions and selects the documents that satisfy all the expressions.
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- `$or`: The `$or` operator performs a logical OR operation on an array of two or more expressions and selects the documents that satisfy at least one of the expressions.
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- `$not`: The `$not` operator performs a logical NOT operation on the specified expression and selects the documents that do not match the expression.
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- `$type`: The `$type` operator matches documents where a specified field has a specific [BSON](../../files/BSON.md) type.
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- `$regex`: The `$regex` operator matches documents where a specified field matches a [regular expression](../../tools/Regex.md).
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- `$text`: The `$text` operator performs a text search on the specified field(s).
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- `$elemMatch`: The `$elemMatch` operator matches documents where a specified array field contains at least one element that matches all the specified conditions.
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- `$size`: The `$size` operator matches documents where a specified array field has a specific size.
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- `$exists`: The `$exists` operator matches documents that contain or do not contain a specified field, including documents where the field value is `null`.
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**Example:**
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```js
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db.users.find(
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{
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$and: [
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{ status: "active" },
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{ age: { $gt: 28 } }
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]
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}
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)
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```
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### Update Modifiers
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- `$set`: The `$set` operator updates the value of a field in a document.
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- `$unset`: The `$unset` operator removes a field from a document.
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- `$inc`: The `$inc` operator increments the value of a field in a document.
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- `$mul`: The `$mul` operator multiplies the value of a field in a document.
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- `$min`: The `$min` operator updates the value of a field in a document if the new value is lower than the existing value.
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- `$max`: The `$max` operator updates the value of a field in a document if the new value is higher than the existing value.
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- `$rename`: The `$rename` operator renames a field in a document.
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- `$addToSet`: The `$addToSet` operator adds a value to an array field in a document if the value does not already exist in the array.
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- `$push`: The `$push` operator appends a value to an array field in a document.
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- `$pull`: The `$pull` operator removes a value from an array field in a document.
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- `$currentDate`: The `$currentDate` operator sets the value of a field in a document to the current date and time.
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- `$each`: The `$each`¥ operator can be used with `$addToSet` and `$push` to append multiple values to an array field in a document.
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- `$sort`: The `$sort` operator can be used with `$push` to sort the elements in an array field in a document.
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**Example:**
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```js
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db.users.updateOne(
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{ name: "John Doe" },
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{
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$set: { age: 35 },
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$addToSet: { interests: "Hiking" },
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$unset: { status: "" }
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}
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)
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``` |