Create multiple PKs with increments

[OlivierCavadenti]

• Resolve the case when a increments column is created in same time that primary keys. Now you can specify a increments columns with or without primary keys:
  • If a primary key is specified, the increment column is added to composite key,
  • If a primary key is not specified, the increment column is set to primary key.

This two cases works :

knex.schema.createTable('table_multiple_keys', function (t) {
  t.primary(['id', 'second_id', 'other_col']);
  t.increments('id');

  t.string('second_id', 16).notNullable();
  t.integer('other_col').notNullable();
});

knex.schema.createTable('table_multiple_keys', function (t) {
  t.primary(['second_id', 'other_col']);
  t.increments('id');

  t.string('second_id', 16).notNullable();
  t.integer('other_col').notNullable();
});

• Solve tricky cases :

  • SQLite : it's not possible to specify autoincrement with composite key, autoincrement need to be primary key. I solve it by transform primary keys in unique index if autoincrement with primary keys is specified.
  • MYSQL don't support autoincrement without primary keys so it's not possible to add autoincrement column without primary key and alter table to add primary key in second query. I solve it by add classic int column, add composite primary key and transform the column to autoincrement.

• Closes Cannot create multiple PKs (mixin .increments with .primary) #385

[kibertoad]

@OlivierCavadenti Great job, as always! Do you think this needs additional documentation?