Exploring the intricacies of managing nested data in a Firebase Database (web)

Question

Exploring the intricacies of managing nested data in a Firebase Database (web)

I understand this question may have similarities to others already asked, so my apologies in advance. I am seeking a clear, up-to-date solution that aligns with my expectations.

https://i.sstatic.net/dQ9ih.jpg

If I have an object labeled "Item One", how can I retrieve the array of "subItems" associated with it?

Furthermore, what is the correct method for adding new subitems to that array (including any specific techniques for targeting the array during writing operations rather than just reading)?

It's worth noting that the top-level context for these "items" is db.ref('items').

javascript firebase firebase-realtime-database

Answer 1

Answer №1

To successfully locate an item based on a specific property, it is necessary to execute a query that sorts and filters data using that property as a parameter. For instance:

var reference = firebase.database().ref("items");
var searchQuery = reference.orderByChild("title").equalTo("Item One");
searchQuery.once("value", function(snapshot) {
  snapshot.forEach(function(item) {
    console.log(item.key); // -L8...EMj7P
    console.log(item.child("subItems").val()); // displays the sub items
    // console.log(item.ref.child("subItems").push().set(...)); // adds a sub item
  });
});

It's important to note that structuring nested data types in Firebase Database is considered an anti-pattern, as it often leads to complications later on. A preferable approach would be to have two separate top-level lists (e.g. items and subItems) using the same keys for reference:

items: {
  -L8...EMj7P: {
    title: "Item One"
  }
},
subItems: {
  -L8...EMj7P: {
    ...
  }
}

Answer 2

To successfully locate an item based on a specific property, it is necessary to execute a query that sorts and filters data using that property as a parameter. For instance:

var reference = firebase.database().ref("items");
var searchQuery = reference.orderByChild("title").equalTo("Item One");
searchQuery.once("value", function(snapshot) {
  snapshot.forEach(function(item) {
    console.log(item.key); // -L8...EMj7P
    console.log(item.child("subItems").val()); // displays the sub items
    // console.log(item.ref.child("subItems").push().set(...)); // adds a sub item
  });
});

It's important to note that structuring nested data types in Firebase Database is considered an anti-pattern, as it often leads to complications later on. A preferable approach would be to have two separate top-level lists (e.g. items and subItems) using the same keys for reference:

items: {
  -L8...EMj7P: {
    title: "Item One"
  }
},
subItems: {
  -L8...EMj7P: {
    ...
  }
}

Exploring the intricacies of managing nested data in a Firebase Database (web)

Answer №1

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