Sequelize Postgres - How to use ON CONFLICT for unique?

Question

I am implementing sequelize into my NodeJS application. Before this, I was using a written INSERT query that used ON CONFLICT (field) DO NOTHING to handle not inserting records where a value needed to be unique.

const sql = 'INSERT INTO communications (firstname, lastname, age, department, campus, state, message_uuid) VALUES ($1, $2, $3, $4, $5, $6, $7) ON CONFLICT (message_uuid) DO NOTHING';

const values = [val.firstName, val.lastName, val.age, val.department, val.campus, val.state, message_uuid];

Is there support for this in sequelize where I can define the same thing within a model? Or perhaps a better way to handle it?

Essentially, if a record already exists in the table in the column with message_uuid = 123 and another record try's to insert that has that same value, it ignores it and does nothing.

Answer 1

You can use public static bulkCreate(records: Array, options: Object): Promise<Array> method with options.ignoreDuplicates.

Ignore duplicate values for primary keys? (not supported by MSSQL or Postgres < 9.5)

Besides, it's important to add a unique constraint for the message_uuid field on the model. So that the query will use ON CONFLICT DO NOTHING clause of Postgres.

For example, "sequelize": "^5.21.3" and postgres:9.6:

import { sequelize } from '../../db';
import { Model, DataTypes } from 'sequelize';

class Communication extends Model {}
Communication.init(
  {
    firstname: DataTypes.STRING,
    lastname: DataTypes.STRING,
    age: DataTypes.INTEGER,
    message_uuid: {
      type: DataTypes.INTEGER,
      unique: true,
    },
  },
  { sequelize, tableName: 'communications' },
);

(async function test() {
  try {
    await sequelize.sync({ force: true });
    // seed
    await Communication.create({ firstname: 'teresa', lastname: 'teng', age: 32, message_uuid: 123 });
    // test
    await Communication.bulkCreate([{ firstname: 'teresa', lastname: 'teng', age: 32, message_uuid: 123 }], {
      ignoreDuplicates: true,
    });
  } catch (error) {
    console.log(error);
  } finally {
    await sequelize.close();
  }
})();

Execution result:

Executing (default): DROP TABLE IF EXISTS "communications" CASCADE;
Executing (default): DROP TABLE IF EXISTS "communications" CASCADE;
Executing (default): CREATE TABLE IF NOT EXISTS "communications" ("id"   SERIAL , "firstname" VARCHAR(255), "lastname" VARCHAR(255), "age" INTEGER, "message_uuid" INTEGER UNIQUE, PRIMARY KEY ("id"));
Executing (default): SELECT i.relname AS name, ix.indisprimary AS primary, ix.indisunique AS unique, ix.indkey AS indkey, array_agg(a.attnum) as column_indexes, array_agg(a.attname) AS column_names, pg_get_indexdef(ix.indexrelid) AS definition FROM pg_class t, pg_class i, pg_index ix, pg_attribute a WHERE t.oid = ix.indrelid AND i.oid = ix.indexrelid AND a.attrelid = t.oid AND t.relkind = 'r' and t.relname = 'communications' GROUP BY i.relname, ix.indexrelid, ix.indisprimary, ix.indisunique, ix.indkey ORDER BY i.relname;
Executing (default): INSERT INTO "communications" ("id","firstname","lastname","age","message_uuid") VALUES (DEFAULT,$1,$2,$3,$4) RETURNING *;
Executing (default): INSERT INTO "communications" ("id","firstname","lastname","age","message_uuid") VALUES (DEFAULT,'teresa','teng',32,123) ON CONFLICT DO NOTHING RETURNING *;

Check the database, there is only one row as expected.

node-sequelize-examples=# select * from communications;
 id | firstname | lastname | age | message_uuid 
----+-----------+----------+-----+--------------
  1 | teresa    | teng     |  32 |          123
(1 row)