问题
In my program, I'd like to create a new post named Column contains of many categoris. Also, a category can contain of many posts.(N:M)
So I tried to add a category to the post, but it failed. Here is the code I've tried: However, no errors are output to the log.
for(var i in column_categorys) {
const category = await Category.findOrCreate({
where : {
category_name: column_categorys[i],
}
})
.then(resolve => {
return resolve;
})
.catch(function(error) {
isFail = true;
return null;
});
await column.addCategory(
category.id,
{ through:
{ selfGranted: false }
}
)
.catch(err => {
console.log(err);
});
}
column_info.js
const Sequelize = require('sequelize');
module.exports = class Column extends Sequelize.Model {
static init(sequelize) {
return super.init({
column_title: {
type: Sequelize.STRING(200),
allowNull: false,
unique: true,
},
column_content_text: {
type: Sequelize.STRING(10000),
allowNull: false,
},
column_content_html: {
type: Sequelize.STRING(10000),
},
column_thumbnail_url: {
type: Sequelize.STRING(300),
},
}, {
sequelize,
timestamps: true,
underscored: true,
modelName: 'Column',
tableName: 'columns',
paranoid: true,
charset: 'utf8',
collate: 'utf8_general_ci',
});
}
static associate(db) {
db.Column.belongsToMany(db.Category, {
through: 'ColumnCategory',
unique: false,
});
db.Column.belongsToMany(db.Tag, {
through: 'ColumnTag',
unique: false,
});
}
};
category_info.js
const Sequelize = require('sequelize');
module.exports = class Category extends Sequelize.Model {
static init(sequelize) {
return super.init({
category_name: {
type: Sequelize.STRING(50),
allowNull: false,
unique: true,
},
}, {
sequelize,
timestamps: false,
underscored: true,
modelName: 'Category',
tableName: 'categorys',
paranoid: false,
charset: 'utf8',
collate: 'utf8_general_ci',
});
}
static associate(db) {
db.Category.belongsToMany(db.Column, {
through: 'ColumnCategory',
unique: false,
});
}
};
model/index.js
const Sequelize = require('sequelize');
const User = require('./user');
const Baby = require('./baby_info');
const UserCase = require('./user_case');
const Column = require('./column_info');
const Tag = require('./tag_info');
const Category = require('./category_info');
const env = process.env.NODE_ENV || 'development';
const config = require(__dirname + '/../config/config')[env];
const db = {};
const sequelize = new Sequelize(config.database, config.username, config.password, config);
db.sequelize = sequelize;
db.User = User;
db.Baby = Baby;
db.UserCase = UserCase;
db.Column = Column;
db.Tag = Tag;
db.Category = Category;
User.init(sequelize);
Baby.init(sequelize);
UserCase.init(sequelize);
Column.init(sequelize);
Tag.init(sequelize);
Category.init(sequelize);
User.associate(db);
Baby.associate(db);
UserCase.associate(db);
Column.associate(db);
Tag.associate(db);
Category.associate(db);
module.exports = db;
Could you tell me what part of this code I've used relationship queries incorrectly?
Latest Version
let getColumn = async function(req, res) {
const result = await Column.findOne({
where: {
column_title: req.body.column_name,
},
include: Category,
});
res.send({result: result});
}
let insertColumn = async function(req, res) {
let isFail = false;
let column_title = req.body.title;
let column_content_text = req.body.contentText;
let column_content_html = req.body.contentHTML;
let column_categorys = req.body.categoris;
let column_tags = req.body.tags;
let column_thumbnail_url = process.env.CDN_ENDPOINT;
column_thumbnail_url += column_title;
column_thumbnail_url += '/';
column_thumbnail_url += '0.png';
await sequelize.transaction(async transaction => {
try {
const column = await Column.create({
column_title: column_title,
column_content_text: column_content_text,
column_content_html: column_content_html,
column_thumbnail_url: column_thumbnail_url,
}, {transaction: transaction});
for(var i in column_categorys) {
const category = await Category.findOrCreate({
where : {
category_name: column_categorys[i],
},
transaction,
});
await column.addCategory(
category.id,
{ transaction },
);
}
for(var j in column_tags) {
const tag = await Tag.findOrCreate({
where : {
tag_name: column_tags[j],
},
transaction,
});
await column.addTag(
tag.id,
{ transaction },
);
}
} catch (err) {
console.log(err);
isFail = true;
}
});
if(isFail) {
res.json({
responseCode: 404,
responseMsg: 'Fail'
});
} else {
res.json({
responseCode: 400,
responseMsg: 'Success'
});
}
}
The responseCode is 400, and there is no error message. But Nothing is in ColumnCategory.
And next one is the logging message.
0|app | 21-01-03 11:27:28: Executing (9904bd92-1a06-4f58-853f-9517d560ca50): START TRANSACTION;
0|app | 21-01-03 11:27:28: Executing (9904bd92-1a06-4f58-853f-9517d560ca50): INSERT INTO `columns` (`id`,`column_title`,`column_content_text`,`column_content_html`,`column_thumbnail_url`,`created_at`,`updated_at`) VALUES (DEFAULT,?,?,?,?,?,?);
0|app | 21-01-03 11:27:28: Executing (9904bd92-1a06-4f58-853f-9517d560ca50): SAVEPOINT `9904bd92-1a06-4f58-853f-9517d560ca50-sp-1`;
0|app | 21-01-03 11:27:28: Executing (9904bd92-1a06-4f58-853f-9517d560ca50): SELECT `id`, `category_name` FROM `categorys` AS `Category` WHERE `Category`.`category_name` = 'category1';
0|app | 21-01-03 11:27:28: Executing (9904bd92-1a06-4f58-853f-9517d560ca50): SAVEPOINT `9904bd92-1a06-4f58-853f-9517d560ca50-sp-2`;
0|app | 21-01-03 11:27:28: Executing (9904bd92-1a06-4f58-853f-9517d560ca50): SELECT `id`, `category_name` FROM `categorys` AS `Category` WHERE `Category`.`category_name` = 'category2';
0|app | 21-01-03 11:27:28: Executing (9904bd92-1a06-4f58-853f-9517d560ca50): SAVEPOINT `9904bd92-1a06-4f58-853f-9517d560ca50-sp-3`;
0|app | 21-01-03 11:27:28: Executing (9904bd92-1a06-4f58-853f-9517d560ca50): SELECT `id`, `tag_name` FROM `tags` AS `Tag` WHERE `Tag`.`tag_name` = 'tag1' LIMIT 1;
0|app | 21-01-03 11:27:28: Executing (9904bd92-1a06-4f58-853f-9517d560ca50): SAVEPOINT `9904bd92-1a06-4f58-853f-9517d560ca50-sp-4`;
0|app | 21-01-03 11:27:28: Executing (9904bd92-1a06-4f58-853f-9517d560ca50): SELECT `id`, `tag_name` FROM `tags` AS `Tag` WHERE `Tag`.`tag_name` = 'tag2' LIMIT 1;
0|app | 21-01-03 11:27:28: Executing (9904bd92-1a06-4f58-853f-9517d560ca50): COMMIT;
0|app | 21-01-03 11:27:28: POST /api/column 200 55.857 ms - 73
回答1:
The troublemaker was FindOrCreate!
it returns Object, boolean value(it means a new row is created)
so, the result has to be divided into two variables.
For example,
const [category, created] = await Category.findOrCreate()
After fixing this part in the latest version, it worked fine!
Of course, addCategory(category), addCategory(category.id) both worked!
回答2:
You shouldn't use then/catch along with await, use try/catch to catch any errors:
try {
for(columnCategory of column_categorys) {
const category = await Category.findOrCreate({
where : {
category_name: column_categorys[i],
}
})
await column.addCategory(
category.id,
{ through:
{ selfGranted: false }
}
);
}
} catch (err) {
console.log(err);
}
Also I recommend to use a transaction when you perform several CRUD-operations. That way your modified data will be consistent. This could be achieved like this:
await sequelize.transaction(async transaction => {
try {
for(columnCategory of column_categorys) {
const category = await Category.findOrCreate({
where : {
category_name: column_categorys[i],
},
transaction
})
await column.addCategory(
category.id,
{ through:
{ selfGranted: false },
transaction
}
);
}
} catch (err) {
console.log(err);
}
});
来源：https://stackoverflow.com/questions/65543213/how-to-add-child-row-in-related-table-sequelzie-nm-relationship