Snapshots capture a session's datasets in a DataChat object. You can use snapshots to:
- Capture a time slice of a live-updating data stream.
- Re-use a dataset in a different session.
- Share the datasets from a session with another user.
- Update large datasets at convenient times from a database.
Open a new DataChat session.
"BikeShare.xlsx" includes multiple sheets, the "All Datasets" table opens as a popup. The "All Datasets" table shows that the BikeShare.xlsx file contains three datasets: BikeShare, SeasonDecode, and WeatherDecode.
Click "BikeShare" to set it as the current dataset.
Click Plot to open the Chart Builder. By default, the form is set to show a scatter chart, but we can change the chart type by clicking on the icons along the top left of the form. Select:
- chart type: Bar Chart
- X-Axis: seasonCode
- Y-Axis: casualRiders.
Click Submit to build the chart. We can see that seasonCode doesn't give us very much information, let alone an informative chart. Let's extend the BikeShare dataset with the other two datasets. Close the scatter chart popup.
Click Dataset > Extend in the sidebar to open the Extend form.
DataChat assesses whether the current dataset ("BikeShare") matches other dataset columns in the current session – "BikeShare" and "SeasonDecode" share "seasonCode", and "BikeShare" and "WeatherDecode" share "weatherSituation". Note that "worldcities_sample" doesn't share any columns with "BikeShare".
We want to extend on "seasonCode", so we'll click Submit, to accept the step shown at the bottom of the form, that corresponds to entering in the GEL input field:
Extend the dataset BikeShare with the dataset SeasonDecode
We can also click "specify column join key" and stipulate the columns explicitly.
DataChat adds the "season" column to BikeShare and saves the new dataset as BikeShare_Extend.
Add "WeatherDecode" to "BikeShare_Extend". With "BikeShare_Extend" highlighted as the current dataset, click Dataset > Extend and select "Weather_Decode" as the dataset to extend with.
By default, DataChat:
- Identifies "weatherSituation" as equal in both datasets.
- Adds the "weather" and "weatherDetails" columns to BikeShare_Extend.
- Saves the new dataset as BikeShare_Extend_Extend.
Click Plot to open the Chart Builder. Select Bar Chart for type, "season" for the X-axis, and "casualRiders" for the Y-axis. Under Optional Fields, select "all riders" for Overlay and "weatherSituation" for Slider.
Click Submit to save the plot.
Save a Snapshot
Click Save in the sidebar, select "Snapshot", enter "AllBikeSnap", and click Submit.
The log displays a success message.
Only one snapshot can be saved per session, so if a snapshot of the same name existed, DataChat prompts you to overwrite or to save the snapshot to a new name. If another snapshot exists in the same session, it is overwritten with the new snapshot and the new name.
Return to the homepage – click the DataChat icon in the upper leftmost corner of the page.
Click Snapshots in the sidebar of the homepage and select "AllBikeSnap". Right-click to show the snapshot menu.
Select Edit Snapshot.
The Snapshot Editor shows the steps that are needed to build the datasets in the snapshot object. Note that the
Plotskill steps are not included – they were trimmed because they don't affect the datasets. The yellow icon to the left of the snapshot name, "AllBikeSnap" shows that because the session was trimmed, the snapshot should be verified to ensure it works as expected.
Hover to the left of the second line, to reveal the checkbox and select it.
Let's remove the extraneous dataset we didn't use.
Click Cut from the sidebar. The
Load data from the file worldcities_sample.csvline is removed from the snapshot.
If we changed our minds, we could undo our change with Cmd-Z on Mac and Ctrl-Z on Windows.
Click Restart > Continuous to verify the snapshot. The remaining four steps will be tested in the window to the right, and a success message appears. Note that the yellow caution icon changes to a green check mark, to show that the snapshot is verified – it can be pasted directly into a session, or used to start a new session.
Click Save from the sidebar to save the current state of the snapshot.
Use a Snapshot
Click the DataChat icon to return to the homepage and Snapshots. Double-click on the "AllBikeSnap" snapshot. A new session called "AllBikeSnap_1" opens, loading the datasets from the altered and saved snapshot "AllBikeSnap". We can generate new charts or work with the data in different ways than we had in the initial "AllBike" session, which is still available in Sessions from the homepage.