Terminology
用語です。
| MySQL | MongoDB |
|---|---|
| databases | database |
| table | collection |
| row | document |
| column | field |
Commands
公式の情報があるので、こちらを見てほしい。→ https://docs.mongodb.com/manual/reference/sql-comparison/
| MySQL | MongoDB |
|---|---|
| show databases; | show dbs |
| create database new_db; | use new_db |
| use new_db; | use new_db |
| show tables; | show collections または db.getCollectionNames() |
| create table users (name varchar(20)); | db.createCollection("users") |
| drop table users | db.users.drop() |
| desc users; | なし |
| insert into users (name) values ("taro"); | db.users.insertOne( { name: "hoge" } ) |
| update users set name = "maro" where name = "taro"; |
db.users.updateMany( { name: "taro" }, { $set: { name: "maro" } } ) |
| select * from users; | db.users.find() |
| select * from users order by name asc; | db.users.find().sort( { name: 1 } ) |
| select * from users order by name desc; | db.users.find().sort( { name: -1 } ) |
| select * from users limit 1; | db.users.find().limit(1) |
| select count(*) from users; | db.users.count() |
| select name from users where age = 90; | db.users.find( { age: 90 }, { name: 1 } ) |
Null and Missing field
MySQL の場合はシンプル
| MySQL |
|---|
| select * from users where age is null; |
| select * from users where age is not null; |
MongoDB の場合は null と missing があるので少し複雑
| users |
|---|
| { name: "100", age: 100 } { name: "null", age: null } { name: "missing" } |
| MongDB | users.name |
|---|---|
| db.users.find( { age: null } ) | null, missing |
| db.users.find( { age: { $ne: null } } ) | 100 |
| db.users.find( { age: { $exists: true } } ) | 100, null |
| db.users.find( { age: { $exists: false } } ) | missing |
| db.users.find( { \$and: [ { age: { $exists: true } }, { age: null } ] } ) |
null |
| db.users.find({ age: { $type: 10 } }) | null |
| db.users.find( { age: { \$not: { $type: 10 } } } ) | 100, missing |
Docker
Docker のおかげで、それぞれの環境がすぐ使えます。
MySQL
$ docker run --name study-mysql --rm -e MYSQL_ALLOW_EMPTY_PASSWORD=yes mysql:8.0
$ docker exec -it study-mysql bash
root@51c68a47680f:/# mysql
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
4 rows in set (0.00 sec)
MongoDB
$ docker run --name study-mongo --rm mongo:4.2
$ docker exec -it study-mongo bash
root@c2ab8e8878c3:/# mongo
> show dbs
admin 0.000GB
config 0.000GB
local 0.000GB
GUI
この辺が王道かと。MongoDB Compass 使いやすいです。