[英]Create Composite Primary Key From Association in Sequelize
I have two models: Person
and Team
我有两个模式:
Person
和Team
Lets just say the models are simple (just assume basic string/int types): 可以说模型很简单(假设基本的字符串/整数类型):
team:
id
name
ownerId
and 和
person:
id
name
I want to represent the associations between these two models such that a Person can belong to many Teams and a Team can belong to many Persons (ie a many to many relationship). 我想代表这两个模型之间的关联,以便一个人可以属于多个团队,一个团队可以属于多个人(即多对多关系)。
To do this is straight forward in Sequelize: 为此,在Sequelize中很简单:
Team.belongsToMany(Person, {through: 'TeamPerson'})
Person.belongsToMany(Team, {through: 'TeamPerson'})
This creates a new table called TeamPerson
with both teamId
and personId
. 这将创建一个名为
TeamPerson
的新表,其中包含teamId
和personId
。 I assume the primary key of this table is a composite of both IDs. 我假设此表的主键是两个ID的组合。
I also want each team to have a captain: 我也希望每个团队都有一个队长:
Team.belongsTo(Person {as: 'captain'})
This will add captainId
to the Team model. 这会将
captainId
添加到团队模型。
Here is my issue, I want a Person to be able to create a Team, but I don't want them to be able to create two teams with the same name. 这是我的问题,我希望一个人能够创建一个团队,但是我不希望他们能够创建两个具有相同名称的团队。 I do, however, want to allow other Persons to create a team with the same name as other Persons.
但是,我确实希望允许其他人创建一个与其他人同名的团队。 So user ID 1 could not have two teams named "Falcons" but user ID 1 can have one team named "Falcons" and user ID 2 could have a team named "Falcons".
因此,用户ID 1不能有两个名为“ Falcons”的团队,但是用户ID 1可以有一个名为“ Falcons”的团队,而用户ID 2可以有一个名为“ Falcons”的团队。
Essentially the name and captainId should be a composite primary key on the Team table. 本质上,name和captainId应该是Team表上的复合主键。 Can anyone give me a tip as to how I might achieve this?
谁能给我一个小窍门,告诉我如何实现这一目标?
You could query for a previously existing person/project before allowing a new project to be created... roughly: 您可以在允许创建新项目之前查询以前存在的人/项目...大致:
Person.findAll({
attributes: ['id'],
include: [{
model: Team,
where : { name : ***TEAM_NAME_PARAM*** }
attributes: [
[Sequelize.fn('count', 'id'), 'number_of_teams']
]
}],
where: { id : ***USER_ID_PARAM***},
group: ['id']
})
.then(myTeams => {
if (myTeams.length == 0 || myTeams.Team.number_of_teams == 0) {
// proceed with creating new team
} else {
// give some error message (you already have a team with that name)
}
...
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.