Find By ID Tutorial

Retrieving an entity by its unique identifier is a common operation in any database system. With Onyx Database, you can efficiently retrieve entities using the findById method. This tutorial demonstrates how to use findById to retrieve an entity.

Steps to Retrieve an Entity by ID (Onyx Cloud Database)

1

Invoke the findById Method

Use the findById method to retrieve the entity by its unique identifier.
1// Basic lookup by primary key
2const season = await db.findById(Season, 2015);
3
4// Optionally hydrate resolver-backed fields when they exist
5const seasonWithStats = await db.findById(Season, 2015, {
6    resolvers: ['teamStats'],
7});
  • The findById method expects the identifier of the entity you are looking for.
  • If the entity does not exist, findById returns null.
  • To fetch resolver-backed attributes, pass an options object as the third argument with a resolvers array (for example, db.findById(Season, 2015, { resolvers: ["teamStats"] })). This is optional—leave it out for entities without resolvers.
2

Confirm the Entity Was Retrieved

Check if the returned entity is not null and use it as needed.
1if (season != null) {
2    console.log(`The season has ${season.conferences.size} conferences!`);
3}
Next Tutorial: List

Important Notes

  • The findById method is optimized for retrieving entities by their primary keys.
  • If you need to retrieve an entity based on other attributes, consider using the find or query methods.

Troubleshooting

  • Entity Not Found: Ensure that the identifier you are using exists in the database.
  • Incorrect Identifier Type: Verify that the identifier's data type matches the type defined in your entity's primary key.
  • Null Pointer Exceptions: Always check if the returned entity is null before accessing its properties.

Next Steps

Now that you know how to retrieve an entity by its unique identifier, you can explore more advanced querying techniques: