ToolJet can connect to **Cloud Firestore** databases to read and write data.
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## Connection
To establish a connection with the **Cloud Firestore** data source, you can either click on the **+ Add new Data source** button located on the query panel or navigate to the **[Data Sources](/docs/data-sources/overview)** page from the ToolJet dashboard and choose Cloud Firestore as the data source.
ToolJet requires the following to connect to your BigQuery:
- **Private key**
For generating a private key check out **[Firestore's official documentation](https://cloud.google.com/iam/docs/creating-managing-service-account-keys#iam-service-account-keys-create-console)**.
Query results can be transformed using transformations. Read our transformations documentation to see how: **[link](/docs/app-builder/custom-code/transform-data)**
Use this operation to query all the documents in a collection. Check firestore doc **[here](https://firebase.google.com/docs/reference/js/v8/firebase.database.Query)**.
Use this operation for updating the existing document in a collection. Also, it only updates fields if they exist, but doesn't replace an entire object like **[set operation](#set-document)**.
This operation replaces your chosen object with the value that you provide. So if your object has 5 fields, and you use Set operation and pass object with 3 fields, it will now have 3 fields.