Creating custom key for new record in Realtime Database Firebase | Angular.

First you need to do basic setup, you can find documentation here, after that.

1. Import in your service

import { AngularFireDatabase } from ‘@angular/fire/database’;

2. Get instance of database

constructor(private fireDB: AngularFireDatabase,
private fireService: AppFirebaseService) {
}

3. Get reference to your collection ( table ) i.e NoSQL database

tableName = ‘todos’; // You can call it node or collection
dbRef = this.fireDB.database.ref(this.url);
get url() {
   return `${this.tableName}/${USER_ID__AFTER_AUTHENTICATION}`;
}

4. Add item to collection

this.dbRef.child(`YOUR_CUSTOM_UNIQUE_KEY`).set(item);

5. Retrieve data from collection, it will return new changes every time data updates in our collection ( Real time updates✌ )

this.fireDB.list(this.url)
.snapshotChanges()
.pipe(
map(changes => changes.map(
c => ({ key: c.payload.key, …c.payload.val() })
))
, tap((next) => {
// You can use your custom store or ngrx-store or any
// and subscribe to that to get realtime updates and bind to view
}
));

6. Update item in collection

this.dbRef.child(key).update(item);

7. Delete item from collection

this.dbRef.child(key).remove();

Thanks.