KnexJS raw query in migration

Question

I have a problem with the following migration in KnexJS, working with PostgreSQL:

exports.up = (knex) => {
    knex.raw('CREATE EXTENSION IF NOT EXISTS "uuid-ossp"');

    return knex.schema.createTable('car_brands', (table) => {
        table.uuid('brandId').unique().notNullable().primary().defaultTo(knex.raw('uuid_generate_v4()'));
        table.string('name').notNullable().unique();
        table.timestamp('created_at').notNullable().defaultTo(knex.raw('now()'));
        table.timestamp('updated_at').notNullable().defaultTo(knex.raw('now()'));
    });
};

exports.down = (knex) => {
    knex.raw('drop extension if exists "uuid-ossp"');
    return knex.schema.dropTable('car_brands');
};

I am using the UUID type for my default values, by using the
defaultTo(knex.raw('uuid_generate_v4()')).

However, when running the above migration, by:

knex migrate:latest --env development --knexfile knexfile.js --debug true

I get an error that:

function uuid_generate_v4() does not exist

Do you know why the knex.raw() query method is not working?

user_7026928 · Answer

The problem is you are running

knex.raw('CREATE EXTENSION IF NOT EXISTS "uuid-ossp"');

and

knex.schema.createTable('car_brands');

asynchronously, so the first query is not executed before the second one.

Rewrite it using async/await:

exports.up = async (knex) => {
    await knex.raw('CREATE EXTENSION IF NOT EXISTS "uuid-ossp"');

    return knex.schema.createTable('car_brands', (table) => {
        table.uuid('brandId').unique().notNullable().primary().defaultTo(knex.raw('uuid_generate_v4()'));
        table.string('name').notNullable().unique();
        table.timestamp('created_at').notNullable().defaultTo(knex.raw('now()'));
        table.timestamp('updated_at').notNullable().defaultTo(knex.raw('now()'));
    });
};

or using Promises:

exports.up = (knex) => {
    knex.raw('CREATE EXTENSION IF NOT EXISTS "uuid-ossp"')
        .then(() => {
            return knex.schema.createTable('car_brands', (table) => {
                table.uuid('brandId').unique().notNullable().primary().defaultTo(knex.raw('uuid_generate_v4()'));
                table.string('name').notNullable().unique();
                table.timestamp('created_at').notNullable().defaultTo(knex.raw('now()'));
                table.timestamp('updated_at').notNullable().defaultTo(knex.raw('now()'));
            });
        })
};

user_6244340 · Answer

These are the steps I took to resolve this issue in my app with PostgreSQL, Objection and KNEX.

Go to your database to verify your extension is available.
```
postgres=# SELECT * FROM pg_extension;
```
Verify "uuid-ossp" is installed in the database_name you need.
```
database_name=# CREATE EXTENSION "uuid-ossp"
```
Back to your app, go to the KNEX migration file where you are altering your table.
```
t.uuid('user_id').defaultTo(knex.raw('uuid_generate_v4()'));
```
Use the KNEX command to get the Batch running:
```
knex migrate:latest
```
Insert a new raw in your table and verify your UUID has been auto-generated.

I hope these steps can be helpful.

KnexJS raw query in migration

2 Answers