I'm using sequelize for node.js. I define this relationship:
// 1:M - Platform table with Governance status table
dbSchema.Platform_governance.belongsTo(dbSchema.Governance_status, {foreignKey: 'platform_status'});
dbSchema.Governance_status.hasMany(dbSchema.Platform_governance, {foreignKey: 'platform_status'});
So that means I have a table called platform_governance which has a foreign key that points to a governance_status row. A user wants to change this foreign key to point to a different governance_status row.
So I want to first search that this governance_status row the user selected actually exists and is unique, and then make the foreign key point to it. This is what I currently have:
// first I select the platform_governance of which I want to change it's foreign key
dbSchema.Platform_governance.findById(5, {include: [dbSchema.Governance_status]}).then(result => {
// Now I search for the user-requested governance_status
dbSchema.Governance_status.findAll({where:{user_input}}).then(answer => {
// I check that one and only one row was found:
if (answer.length != 1 ) {
console.log('error')
} else {
// Here I want to update the foreign key
// I want and need to do it through the associated model, not the foreign key name
result.set('governance_status', answer[0])
result.save().then(result => console.log(result.get({plain:true}))).catch(err => console.log(err))
}
The result.save() promise returns successfully and the object printed in console is correct, with the new governance_status correctly set. But if I go to the database NOTHING has changed. Nothing was really saved.
Oops just found the problem. When setting associations like this you shouldn't use the set() method. Instead, sequelize creates setters for each association. In my case I had to use setGovernance_status():
// Update corresponding foreign keys
result.setGovernance_status(answer[0])
If anyone finds anywhere in the documentation where this is documented I would appreciate :)
Related
I am using Sequelize in my node js server. I am ending up with validation errors because my code tries to write the record twice instead of creating it once and then updating it since it's already in DB (Postgresql).
This is the flow I use when the request runs:
const latitude = req.body.latitude;
var metrics = await models.user_car_metrics.findOne({ where: { user_id: userId, car_id: carId } })
if (metrics) {
metrics.latitude = latitude;
.....
} else {
metrics = models.user_car_metrics.build({
user_id: userId,
car_id: carId,
latitude: latitude
....
});
}
var savedMetrics = await metrics();
return res.status(201).json(savedMetrics);
At times, if the client calls the endpoint very fast twice or more the endpoint above tries to save two new rows in user_car_metrics, with the same user_id and car_id, both FK on tables user and car.
I have a constraint:
ALTER TABLE user_car_metrics DROP CONSTRAINT IF EXISTS user_id_car_id_unique, ADD CONSTRAINT user_id_car_id_unique UNIQUE (car_id, user_id);
Point is, there can only be one entry for a given user_id and car_id pair.
Because of that, I started seeing validation issues and after looking into it and adding logs I realize the code above adds duplicates in the table (without the constraint). If the constraint is there, I get validation errors when the code above tries to insert the duplicate record.
Question is, how do I avoid this problem? How do I structure the code so that it won't try to create duplicate records. Is there a way to serialize this?
If you have a unique constraint then you can use upsert to either insert or update the record depending on whether you have a record with the same primary key value or column values that are in the unique constraint.
await models.user_car_metrics.upsert({
user_id: userId,
car_id: carId,
latitude: latitude
....
})
See upsert
PostgreSQL - Implemented with ON CONFLICT DO UPDATE. If update data contains PK field, then PK is selected as the default conflict key. Otherwise, first unique constraint/index will be selected, which can satisfy conflict key requirements.
Reading the documentation of Sequelize I'm in some level confused, what Sequelize will provide automatically for us and what we need to explicitly tell it.
I have two models: User and Post. As you have guessed a User can have multiple Posts and a Post belongs only to one User. Setting the respective relationships will look so:
Post.associate = (models) => {
Post.belongsTo(models.users, {
as:'user',
foreignKey: {
name: 'user_id',
allowNull: false
}
}
}
User.associate = (models) => {
User.hasMany(models.posts, {
as:'posts',
onDelete:'CASCADE',
onUpdate:'CASCADE'
}
}
My question is: should I specify the foreignKey one more time when declaring the hasMany association, or it is enough for Sequelize to have the foreignKey in one of the declared relationships between two models (in the example - belongsTo)?
From what I think happens:
Sequelize goes through all your association one by one
If you already provided a foreign key name then fine
Else it will guess/name the foreign key on its own
Like what it says about options.foreignKey in docs e.g. for belongsTo : https://sequelize.org/master/class/lib/model.js~Model.html#static-method-belongsTo (same description for hasOne, hasMany, belongsToMany )
options.foreignKey || string OR object || optional
The name of the foreign key attribute in the source table or an object representing the type definition for the foreign column (see Sequelize.define for syntax). When using an object, you can add a name property to set the name of the column. Defaults to the name of target + primary key of target
If sequelize is guessing your foreignKey names then you will face issues only if your foreignKey name is not matching (tableName + Id) OR (tableName + _ + id)
💡 Hence, better to give foreignKey names on your own to both sides of associations to never face any issues going further.
I am trying to delete and update records in cosmosDB using my graphql/nodejs code and getting error - "Entity with the specified id does not exist in the system". Here is my code
deleteRecord: async (root, id) => {
const { resource: result } = await container.item(id.id, key).delete();
console.log(`Deleted item with id: ${id}`);
},
Somehow below code is not able to find record, even "container.item(id.id, key).read()" doesn't work.
await container.item(id.id, key)
But if I try to find record using query spec it works
await container.items.query('SELECT * from c where c.id = "'+id+'"' ).fetchNext()
FYI- I am able to fetch all records and create new item, so Connection to DB and reading/writing is not an issue.
What else can it be? Any pointer related to this will be helpful.
Thanks in advance.
It seems you pass the wrong key to item(id,key). According to the Note of this documentation:
In both the "update" and "delete" methods, the item has to be selected
from the database by calling container.item(). The two parameters
passed in are the id of the item and the item's partition key. In this
case, the parition key is the value of the "category" field.
So you need to pass the value of your partition key, not your partition key path.
For example, if you have document like below, and your partition key is '/category', you need to use this code await container.item("xxxxxx", "movie").
{
"id":"xxxxxx",
"category":"movie"
}
Ok, I have looked but didn't find anything that worked for me. If you can point me to anything or help my find the solution it would be great.
Let's say I have a "users" table (columns: id, username and name) and a "users_items" table (columns: id_item, id_user, both Foreign Keys)
What I want to do: I want to insert a new user and assign him a default item that everyone should have. For that, I want to create a transaction where everything or nothing is saved. So if (for any reason) I can't give him that item, I want the user creation to fail.
How I do it:
const pgp = require('pg-promise')(
{
capSQL: true // generate capitalized SQL
});
const db = pgp(configuration);
saveUser = (username, name) =>
db.tx (t =>
t.one('INSERT INTO users (username, name) VALUES $1, $2 RETURNING *', [username, name]).then(user =>
t.none ('INSERT INTO users_items (id_user, id_item) VALUES $1, 1', [user.id]).then(()=>
console.log('Everything\'s alright :)');
)
);
What I expect: everything runs perfectly and we are all happy :).
What actually happens: The first instruction is OK, and returns correctly the user with the ID. However, the second one tells me that the constraint fk_id_user is being violated, and perform a ROLLBACK.
The part of it not commiting the first insert is working properly. However, shouldn't the second insert work too? Am I understanding something extremely wrong or is pg-promise not working as expected? Or maybe I need to do something different.. Any help would be appreciated.
How can I add a new row with the update operation
I am using following code
statuscollection.update({
id: record.id
}, {
id: record.id,
ip: value
}, {
upsert: true
}, function (err, result) {
console.log(err);
if (!err) {
return context.sendJson([], 404);
}
});
While calling this first one i will add the row
id: record.id
Then id:value then i have to add id:ggh
How can i add every new row by calling this function for each document I need to insert
By the structure of your code you are probably missing a few concepts.
You are using update in a case where you probably do not need to.
You seem to be providing an id field when the primary key for MongoDB would be _id. If that is what you mean.
If you are intending to add a new document on every call then you probably should be using insert. Your use of update with upsert has an intended usage of matching a document with the query criteria, if the document exists update the fields as specified, if not then insert a new document with the fields specified.
Unless that actually is your goal then insert is most certainly what you need. In that case you are likely to rely on the value of _id being populated automatically or by supplying your own unique value yourself. Unless you specifically want another field as an identifier that is not unique then you will likely want to be using the _id field as described before.