Knex MySQL Migration “Unhandled rejection Error: Transaction query already complete”

Question

I'm new to pretty much everything. I tried using a single migration file to create all the tables in a MySQL database (20 tables).

exports.up = function(knex, Promise) {

function createTable1() {
    return knex.schema.createTableIfNotExists('Table1', (t) => {
      t.increments('id').primary();
      t.string('col_1', 48).unique().notNullable();
      t.timestamps(true, true);
    }).catch((e) => console.log(e));
}

function createTable2() {
    return knex.schema.createTableIfNotExists('Table2', (t) => {
      t.increments('id').primary();
      t.string('col_1', 48).unique().notNullable();
      t.integer('someId').unsigned().references('Table1.id')
      t.timestamps(true, true);
    }).catch((e) => console.log(e));
}

function createTable3() {
    return knex.schema.createTableIfNotExists('Table3', (t) => {
      t.increments('id').primary();
      t.string('col_1', 48).unique().notNullable();
      t.integer('someId').unsigned().references('Table1.id')
      t.integer('someOtherId').unsigned().references('Table2.id')
      t.timestamps(true, true);
    }).catch((e) => console.log(e));
}
... //similar functions for all 20 tables

return Promise.all([
    createTable1()
    .then(createTable2())
    .then(createTable3())
    ...
    .then(createTable20())
    .catch((e) => console.log(e.sql))
  ]);
}

exports.down = function(knex, Promise) {

  return knex.schema.dropTable('Table1')
  .then(knex.schema.dropTable('Table2'))
  .then(knex.schema.dropTable('Table3'))
  ...
  .then(knex.schema.dropTable('Table20'))
  .catch((e) => console.log(e.sql))
};

I expected knex to execute all of the sql queries in one transaction

The migration executes but generates the following error:

Unhandled rejection Error: Transaction query already complete, run with DEBUG=knex:tx for more info

Admittedly I don't have a firm grasp with how to use promises correctly and I understand that the return Promise.all block will not necessarily generate & execute the SQL queries in that same order, but should I even be doing this? Does it make more sense to create a separate migration file for each table?

Answer 1

You are invoking functions in your promise chain instead of chaining them. The first function should be executed and then chained with other functions in the .then . You also seem to be mixing up promise chaining and the usage of Promise.all .

If you want each table to be created sequentially drop the Promise.all and the function calls:

return createTable1()
  .then(createTable2)
  .then(createTable3)
  ...
  .then(createTable20)
  .catch((e) => console.log(e.sql))

If you want to create N tables all at the same time use Promise.all like this:

return Promise.all([createTable1(), createTable2(), ..., createTable20()])