How to call uuid_generate_v4() as a default value for id in pq?

[viktor-ku]

I would greatly appreciate the answer!
Right now it seems like I cannot do that? There is defaultValue, but whatever string it accepts it just passes it like escaped string?

Same is for the dates, but I guess that is the same kind of question.

So, how to call a function to set a default value?

UPD. found escape and it looks like something I would use, but for pq it's set to undefined

[mmkal]

Hi - I need a bit more context here. Which default value? Which id? What is pq?? What's escape?

[viktor-ku]

When writing migration, you have context, which has various methods like createTable and others. For example, one of these methods is escape. Anyway, you have to specify types and in there you've got type, primaryKey, allowNull and others. You also have defaultValue, which I assume setups the default value, however, it doesn't work when writing a function call there like this:

export async function up({context: cx}: {context: QueryInterface}) {
  await cx.createTable(table, {
    id: {
      type: UUID,
      primaryKey: true,
      defaultValue: 'uuid_generate_v4()'
    },
  })
}

So my question is: how to generate a default UUID on the db side of things when inserting a new record? And pq is postgres.

Sorry, for the lack of context, my bad.

Thanks

[viktor-ku]

For anyone wondering I just passed default expression with the type info, which arguably feels very wrong, but hey

export async function up({context: cx}: {context: QueryInterface}) {
  await cx.createTable(table, {
    id: {
      type: 'uuid DEFAULT uuid_generate_v4()',
      primaryKey: true,
    },
  })
}

[viktor-ku]

Sure, it's pretty basic

  const db = new Sequelize(APP_DATABASE, {})
  // ...
  const migrations = new Umzug({
    migrations: {
      glob: `${migrationsDir}/*.ts`
    },
    context: db.getQueryInterface(),
    storage: new SequelizeStorage({sequelize: db}),
    logger: console
  })

Hmm, so you are saying that by specifying table inside of the migration, I actually am using this construction under the hood? Is that right?

sequelize.define('model', {
  uuid: {
    type: DataTypes.UUID,
    defaultValue: DataTypes.UUIDV1,
    primaryKey: true
  }
})

[mmkal]

It has a similar interface I believe yes, though the queryInterface is lower-level. Docs here: https://sequelize.org/master/manual/query-interface.html

Tbh I'm not an expert on sequelize, I don't use it much outside of maintenance of this repo. Umzug aims to be database/framework agnostic, and just-so-happens to support sequelize out of the box.

Hopefully DataTypes can solve your problem here, but if you don't use sequelize outside of migrations and only are using it for dynamic migrations, it might be worth considering @slonik/migrator, which is postgres-only migration tool which promotes writing sql rather than having to learn about all the abstractions of sequelize and how they map to database queries.

[viktor-ku]

Thank you for your help! I will be researching this topic. I see that the migrator prefers sql files, but I really really need to be able to manipulate data in between my migrations. Maybe I am doing something wrong, or I am weird, but I do UPDATE quite a lot in migrations too and it often requires many queries to db. Maybe you know what I am doing wrong?

[mmkal]

Script files are allowed too, that's fine. Personally I usually prefer sql because it makes it easier to know for sure what has run, and reduces lock-in to any given tool. But migrations can be complex so it's not necessarily a bad thing if js/ts is needed. Slonik is a typescript postgres client, it doesn't have multi-dialect support like sequelize. But if you're just using postgres that might not be a problem.

[viktor-ku]

Hey, thank you, I think I will give migrator a try, it sounds reasonable. Indeed, 90% of the time I just need to run sql.