Configuration and use of MongoDB

Two ways to run MongoDB

Check if there are Mongodb:which Mongod

Create DATABASE Storage directory: Mkdir-p/data/db

Check the disk directory for space (typically larger than 4G): DF-LH

Start: A direct start: Mongod--dbpath=/data/db--port=27017

B daemon Start: Mongod--dbpath=/data/db--port=27017--fork--syslog//syslog for system logs It's best to use MongoDB's own logs

Best written: Mongod--dbpath=/data/db--port=27017--fork--log=/var/log/mongod.log

Basic use of MongoDB

On the premise that the daemon is turned on

Running MongoDB

1. 1. MONGO 127.0.0.1:27017
   2. Mongo

Display database: Show DBS

Create DATABASE: Use MyDB//Note The database is only displayed when the number of data bars is >=1

Insert a piece of data in the Users collection: Db.users.insert ({"Name": "Xiao Wang", "Sex": "Male"})

See all collections: Show Collections

Querying all data from the Users collection: Db.users.find () queries the users collection for data that specifies conditions: Db.user.find ({"Name": "Xiao Wang"})

To view the number of users collection data: Db.users.find (). Count () View the number of data bars for the specified condition Db.user.find ({"Name": "Xiao Wang"}). Count ()

Modify data for the Users collection: db.users.update (condition, modify value, configuration parameter) db.users.update ({"Name:" Xiao Wang "},{$set: {" Age ":" ""}},{multi:true})// Multi refers to whether to modify all the data that meets the criteria, by default modify the first bar

Modify data for the Users collection: Db.users.save ({"_id": ObjectId ("5ae81be4ce517088bda1f195"), "name": "Small Week"})//Note _id is a required field

Delete data from the Users collection: Db.users.remove ({"Name": "Xiao Wang"},true)//true indicates whether to delete a single row, by default deleting all data that meets the criteria

Remove removes the entire document and cannot delete the index

To delete all, use drop

Db.users.drop ()

Summary of the difference between save and update: Save must modify a field must be added to all other fields, and update can specify the field modification, with $set: specified can be

　　

Configuration and use of MongoDB