Sequelize Postgres - How to use ON CONFLICT for unique? - sql

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)

Answer 2

see the new UPSERT feature in Sequelize v6:
https://sequelize.org/api/v6/class/src/model.js~model#static-method-upsert
Implementation details:
MySQL - Implemented with ON DUPLICATE KEY UPDATE`
PostgreSQL - Implemented with ON CONFLICT DO UPDATE.
If update data contains PK field, then PK is selected as the default conflict
key. Otherwise first unique constraint/index will be selected, which
can satisfy conflict key requirements.
SQLite - Implemented with ON CONFLICT DO UPDATE
MSSQL - Implemented as a single query using MERGE and WHEN (NOT) MATCHED THEN

Answer 3

as second argument of Model.create you can provide onConflict prop, please read the documentation