Enhanced Entity–Relationship

database.puml

@startuml
' see: http://plantuml.com/classes.html#More
skinparam LineType ortho
skinparam Shadowing false
skinparam Class {
    HeaderBackgroundColor #98BFDA
	BackgroundColor White
	BorderColor #808080
	ArrowColor #8c8c8c
}
!define TABLE(name) class name
!define PK(x) <color:#f0c314><&key></color>**x**
!define FK(x) <color:#dd776c><&key></color>**x**
!define UNIQUE(x) <color:#fe5a63><&underline></color>x
!define VARCHAR(size) {field}VARCHAR(size)
!define CHAR(size) {field}CHAR(size)
!define NOT_NULL(x) <size:9>not null</size>
hide methods
hide stereotypes
hide circle

TABLE(user) {
    PK(id) INTEGER
    UNIQUE(username) VARCHAR(32) NOT_NULL()
    password VARCHAR(64)
}

TABLE(user_profile) {
    PK(user_id) INTEGER
    age SMALLINT
    gender SMALLINT
    birthday DATETIME
}
user_profile }-- user

TABLE(session) {
    PK(id) INTEGER
    FK(user_id) INTEGER NOT_NULL()
    UNIQUE(session_id) VARCHAR(64) NOT_NULL()
}
session }-- user

TABLE(group) {
    PK(id) INTEGER
    name VARCHAR(32) NOT_NULL()
}

TABLE(user_group) {
    FK(user_id) INTEGER
    FK(group_id) INTEGER
    joined_at DATETIME
}
user_group }-- user
user_group }-- group

@enduml