---
id: updating_channels
sidebar_position: 9
title: Updating Channels
---

There are two ways to update a channel using the Stream API - a partial or full update.
A partial update will retain any custom key-value data, whereas a complete update is going to remove any that are unspecified in the API request.

### Partial Update

A partial update can be used to set and unset specific fields when it is necessary to retain additional custom data fields on the object.
AKA a patch style update.

```dart
// Here's a channel with some custom field data that might be useful
var channel = client.channel(type, id: id, extraData: {
  "source": "user",
  "source_detail" :{ "user_id": 123 },
  "channel_detail" :{ "topic": "Plants and Animals", "rating": "pg" }
});

// let's change the source of this channel
await channel.updatePartial({ "set" :{ "source": "system" } });

// since it's system generated we no longer need source_detail
await channel.updatePartial({ "unset": ["source_detail"] });

// and finally update one of the nested fields in the channel_detail
await channel.updatePartial({ "set": { "channel_detail.topic": "Nature" } });

// and maybe we decide we no longer need a rating
await channel.updatePartial({ "unset": ["channel_detail.rating"] });
```

### Full Update (overwrite)

The update function updates all of the channel data.
<b>Any data that is present on the channel and not included in a full update will be deleted.</b>

```dart
await channel.update({
  "name": "myspecialchannel",
  "color": "green",
}, Message(text: "Thierry changed the channel color to green"));
```