The useDql Hook
One hook, one query, live data from Grail:
import { useDql } from "@dynatrace-sdk/react-hooks";
const { data, error, isLoading } = useDql({
query: `fetch dt.entity.host
| fields entity.name, cpuCores, osType
| sort entity.name asc
| limit 20`
});
Two DQL Commands
// Entities
`fetch dt.entity.host | fields entity.name, cpuCores`
// Metrics
`timeseries avg(dt.host.cpu.usage), by:{dt.entity.host}, from:-2h`
// Logs
`fetch logs | filter contains(content, "error") | limit 50`
// Spans (distributed traces)
`fetch spans | filter request.is_root_span == true
| summarize count(), by:{dt.service.name}`
// Problems
`fetch dt.davis.problems, from:now()-24h
| filter not(dt.davis.is_duplicate) and event.status == "ACTIVE"
| fields display_id, event.name, event.category`
// Metric discovery
`fetch metric.series, from:now()-1h
| filter contains(metric.key, "cpu")
| summarize count(), by:{metric.key}`
⚠️ Common DQL pitfalls: loglevel not log.level, by: {field1, field2} needs curly braces, sort `count()` desc needs backticks, filter in(field, "a", "b") not field in ["a","b"].
Which DQL command do you use to query metric time series data?
Handling States
if (isLoading) return <ProgressCircle />;
if (error) return <Text>Error: {error.message}</Text>;
// data.records is an array of rows
⚠️ Always handle loading and error states. DQL queries can take 1-5 seconds.
Data Shape
DQL returns data.records (array of objects) and data.types (column metadata). Strato components like DataTable and TimeseriesChart consume this directly.
💡 Use convertToColumns(data) for DataTable and convertToTimeseries(data) for TimeseriesChart — they handle the conversion automatically.
What React hook fetches DQL data in a Dynatrace App?
What's Next
Module 5 — The Strato component library: DataTable, buttons, layouts.