add column with default value to another column in migration

[hbatalhaStch]

I want to add a new column to my database where its default value will reference another column value.

I have tried this code but didn't work:

import BaseSchema from '@ioc:Adonis/Lucid/Schema'

export default class extends BaseSchema {
  protected tableName = 'users'

  public async up() {
    this.schema.alterTable(this.tableName, (table) => {
      table.date('alt_birthday')
    })
      .then(async () => await this.raw(`UPDATE ${this.tableName} SET alt_birthday = birthday`))
      .then(() => {
        this.schema.alterTable(this.tableName, (table) => {
          table.date('alt_birthday').notNullable().alter()
        })
      })
  }

  public async down() {
    this.schema.alterTable(this.tableName, (table) => {
      table.dropColumn('alt_birthday')
    })
  }
}

This code worked:

import BaseSchema from '@ioc:Adonis/Lucid/Schema'

export default class extends BaseSchema {
  protected tableName = 'users'

  public async up() {
    this.schema.alterTable(this.tableName, (table) => {
      table.date('alt_birthday')
    })

    this.schema.alterTable(this.tableName, async (table) => {
      await this.raw("UPDATE users set alt_birthday = birthday")
    })

    this.schema.alterTable(this.tableName, (table) => {
      table.date('alt_birthday').notNullable().alter()
    })
  }

  public async down() {
    this.schema.alterTable(this.tableName, (table) => {
      table.dropColumn('alt_birthday')
    })
  }
}

but I am not if this is the best way to achieve what I want

[thetutlage]

Why you think the code that works is not the best approach?

[hbatalhaStch]

Because of this part of the code that works:

this.schema.alterTable(this.tableName, async (table) => {
    await this.raw("UPDATE users set alt_birthday = birthday")
})

This is inside the alterTable function, but the operations inside don't actually alter the table.
I was thinking these operations are reserved for this function but using it instead does not work either.

To be clear, I don't think that the code that works is not the best approach, I am wondering/asking if there is a better approach.

[thetutlage]

You can use the defer method instead.

this.defer((db) => {
  db.raw('UPDATE users set alt_birthday = birthday')
})

[hbatalhaStch]

import BaseSchema from '@ioc:Adonis/Lucid/Schema'

export default class extends BaseSchema {
  protected tableName = 'users'

  public async up() {
    this.schema.alterTable(this.tableName, (table) => {
      table.date('alt_birthday')
    })

    this.defer((db) => {
      db.raw('UPDATE users set alt_birthday = birthday')
    })

    this.schema.alterTable(this.tableName, (table) => {
      table.date('alt_birthday').notNullable().alter()
    })
  }

  public async down() {
    this.schema.alterTable(this.tableName, (table) => {
      table.dropColumn('alt_birthday')
    })
  }
}

I get this error:
[ error ] alter table "users" alter column "alt_birthday" set not null - column "alt_birthday" of relation "users" contains null values

It seems that the second alterTable method runs before the defer method