"knex.decimal()" creates a column of type float not decimal - tested with sqlite3 and with better-sqlite3

[hassanallaham]

Environment

Knex version: 3.1.0
Database + version: Sqlite 3.42.0
Client + version: sqlite3 ^5.1.7 / better-sqlite3 ^9.2.2
OS: Linux Mint 21.3

Bug

Accodrding to the docs (https://knexjs.org/guide/schema-builder.html#decimal) this should create a column of type decimal
but it creates a column of type float not decimal (Tested with sqlite database and with both clients)

Reduced test code:

import knex from 'knex';

const db = knex({
      client: 'sqlite3',
      connection: { filename: '/db.sqlite3' },
      debug: true,
      asyncStackTraces: true,
      log: {
            warn(message) {
                  console.log(`Warning from knex: ${message}`);
            },
            error(message) {
                  console.log(`Error from knex: ${message}`);
            },
            deprecate(message) {
                  console.log(`Deprecate from knex: ${message}`);
            },
            debug(message) {
                  console.log(`Debug from knex stringified: ${JSON.stringify(message)}`);
            },
      },
      migrations: { tableName: 'migrations' },
      useNullAsDefault: true
});

const test = async () => {
      await db.schema.table('testTable', async (table) => {
            table.decimal('newCol', 6, 2);
      });
      return true;
};

test().then(() => {
      console.log('created');
      process.exit(0);
});

and what is shown in terminal:

Debug from knex stringified: [{"sql":"alter table `testTable` add column `newCol` float","bindings":[]}]

created

Notice the Debug result in terminal where you can find it uses "float" and not "decimal"

[mohammedbalila]

Hey @rluvaton
I found that in sqlit3 column compiler double, decimal, and floating are all converted to float.
I think sqlite3 supports all three types, I can change that and create a PR. But is there a reason for this behaviour?