Events can be used to listen for specific events that happen in the database. All events will conform to the InanoSQLDatabaseEvent interface.

You can listen to events with nSQL().on("event", callback") and disable listening with nSQL().off("even", callback).

The supported database events are:

  • connect called when the database adapter successfully connects to the backend
  • ready called when tables are configured and the nanoSQL is ready for queries.
  • disconnect called when the database adapter has disconnected.

Database events ignore table selection and aren't effected by which table is selected in the query. For example nSQL("users").on("ready", ...) will do exactly the same thing as nSQL().on("ready", ...).

You can attach database events before a database has been created, but you must first select the new database with useDatabase if you're using a custom database name.

// listen for ready event on database "my-db"
nSQL().useDatabase("my-db").on("ready", () => {


// create/connect to the database
    id: "my-db",
    mode: "PERM",
    tables: [...]

Supported table specific events are:

  • select called when a row is selected on this table
  • change called when a row is updated, inserted or deleted from this table
  • delete called when a row is removed from this table
  • upsert called when a row is updated or added to this table.

With table specific events, you must select the table you intend to listen to before calling the .on() or .off() event listeners.

Important note about change and upsert events

When the event is triggered, there will always be a result property in the event object containing the final row that was added or modified. However, if the row was modified an additional property named oldRow will be present which contains the state of the row before the query. New rows will not have a oldRow property in the event object.

Last Updated: 7/23/2019, 8:42:41 AM