Q. SQL vs MongoDB 比較
| SQL | MongoDB |
|---|---|
| database | database |
| table | collection |
| row | document |
| column | field |
More Info : MongoDB 与 MySQL 深入对比
Q. Windows 如何啓動mongodb?
mongod --storageEngine=mmapv1 --dbpath [your-path]
mongod --storageEngine=mmapv1 --dbpath D:\MongoDB\mydb
mongod --storageEngine=mmapv1 --dbpath D:\Misc\MongoDB\Data\mydb
Q. 如何使用mongo shell ?
mongo
mongo --version 查詢目前mongo版本
Q. MongoDB Shell Commands
| Command | Description |
|---|---|
| db.stat() | show db info |
| show dbs | show existing databases |
| show collections | show collections in current database |
| use [database] | switch to db [database] |
| db.[collection].insert([document]) | insert a document into a collection, MongoDB willcreate the [collection] if it doesn’t exist |
| db.[collection].drop() | delete collection |
| db.[collection].find() | query all documents in collection |
| db.[collection].find([condition]) | query documents have specific field value |
| TODO: 條件運算子 |
ex:
db.employee.insert({"name":"welen","country":"tw", "age":"35"})
db.employee.find({"age":"35"})
Q. MongoDB $regex Query Operators
Ans. $regex provides regular expression capabilities for pattern matching strings in queries
Syntax
{ <field>: { $regex: /pattern/, $options: '<options>' } }
{ <field>: { $regex: /pattern/<options> } }
^ for the start
$ for the end
.* for unspecific string
options
i for case insensitively
ex:
match all documents where name field contains w
db.employee.find({name: {$regex: /w/}})
match all documents where name field end with n
db.employee.find({name: {$regex: /n$/}})
match all documents where name field start with 8
db.employee.find({name: {$regex: /^8/}})
match all documents contains m, follows by a string with line at end
db.products.find( { description: { $regex: /m.*line/, $options: 'si' } } )