Query Nodes

Query nodes load data from files and feed it to connected charts.

What Query Nodes Do

A query node reads a CSV or JSON file and caches the data. Connected chart nodes receive this data through canvas edges. The query node displays a preview table showing the first rows.

Creating a Query Node

Edit your canvas file and add a text node with dgExtension:

{
  "id": "query-sales",
  "type": "text",
  "text": "## Sales Data\n\nSource: `data/sales.csv`",
  "dgExtension": {
    "nodeType": "query",
    "query": "file: data/sales.csv"
  },
  "x": 0,
  "y": 0,
  "width": 400,
  "height": 300
}

Query Configuration

The query property specifies the data source:

file: data/sales.csv

Supported Formats

Format	Extension	Example
CSV	.csv	file: data/sales.csv
JSON	.json	file: data/metrics.json

File Resolution

DataGlass searches for files in this order:

1. Exact path from vault root
2. Inside data/ folder

If you specify file: sales.csv, DataGlass first tries sales.csv, then data/sales.csv.

Preview Table

Query nodes display a preview of loaded data:

• First 5 rows
• First 5 columns
• Total row count

This helps verify the correct file loads before connecting charts.

Connecting to Charts

Draw a canvas edge from the query node to a chart node. The chart must have data: { upstream: true } in its configuration.

[Query: sales.csv] ──edge──> [Chart: bar]

One query can connect to multiple charts. Each receives the same data.

Data Caching

Query results cache for 60 seconds:

• Multiple charts share one query result
• Fast chart re-renders
• Reduced file reads

The cache clears when you close the canvas or the plugin unloads.

Troubleshooting

Problem	Cause	Solution
No preview table	File not found	Check file path and extension
Empty preview	File empty or malformed	Validate CSV/JSON format
Wrong data	Wrong file path	Verify path in query config