是一对一还是多对一？

Question

I'm using sequelize with mssql.

I try to create One-to-One relation like in this picture :

So I use the code from sequelize docs:

const Player = this.sequelize.define('player', {/* attributes */});
const Team  = this.sequelize.define('team', {/* attributes */});

Player.belongsTo(Team); // Will add a teamId attribute to Player to hold the primary key value for Team

I got Many-To-One as you can see in the picture

So I have try to do:

const Player = sequelize.define('player', { /* attributes */ });
const Team  = sequelize.define('team', { /* attributes */ });

Player.belongsTo(Team);
Team.hasOne(Player);

Same result.

How can I do one-to-one relation?

Edit

For this code:

const Player = sequelize.define('player', { /* attributes */ });
const Team  = sequelize.define('team', { /* attributes */ });

Player.hasOne(Team);

This is what sequelize does:

IF OBJECT_ID('[teams]', 'U') IS NOT NULL DROP TABLE [teams];
IF OBJECT_ID('[players]', 'U') IS NOT NULL DROP TABLE [players];
IF OBJECT_ID('[players]', 'U') IS NOT NULL DROP TABLE [players];
IF OBJECT_ID('[players]', 'U') IS NULL CREATE TABLE [players] ([id] INTEGER NOT NULL IDENTITY(1,1) , [createdAt] DATETIMEOFFSET NOT NULL, [updatedAt] DATETIMEOFFSET NOT NULL, PRIMARY KEY ([id]));
EXEC sys.sp_helpindex @objname = N'[players]';
IF OBJECT_ID('[teams]', 'U') IS NOT NULL DROP TABLE [teams];
IF OBJECT_ID('[teams]', 'U') IS NULL CREATE TABLE [teams] ([id] INTEGER NOT NULL IDENTITY(1,1) , [createdAt] DATETIMEOFFSET NOT NULL, [updatedAt] DATETIMEOFFSET NOT NULL, [playerId] INTEGER NULL, PRIMARY KEY ([id]), FOREIGN KEY ([playerId]) REFERENCES [players] ([id]) ON DELETE SET NULL);
EXEC sys.sp_helpindex @objname = N'[teams]';

And still the problem exist.

Answer 1

You should use hasOne() method. not belongsTo() that's it :)

Answer 2

According to sequelize docs you can use "belongsTo" when information about association is present in the source model and "hasOne" when information about association is present in the target model.

In your case, the information about association is present in the source model (playerId exists on the team model) thus what you should do is:

Team.belongsTo(Player)
Player.hasOne(Team)

and what you did in the edited answer is correct and should suffice.