Purpose
Shows data to the user at the selected stage. Lets the user inspect a limited number of rows or all rows, export to Excel and continue. The table is unchanged.
Inputs and outputs
One in input. With terminal=false, data continues through out; with terminal=true, there is no output and the branch ends.
Parameters
| Parameter | Settings and values | Options and limits |
|---|---|---|
terminal | End the branch with this block. | Default: disabled |
enabled | Open the preview during execution. | Default: enabled |
row_limit | The initial number of displayed rows: 100 by default; an empty value means all rows. | Default: 100 |
wizard | Show the block as a step in the execution wizard. | Default: enabled |
Step-by-step configuration
- Place the block after an important transformation.
- Set the initial limit, for example 100 rows.
- Choose whether to end the branch and whether to show the step in the wizard.
- Run the flow, check headings, types and values, then continue.
Rules and diagnostics
- row_limit limits the initial display, not the amount of data passed to the next block.
- Turning off enabled prevents the preview from opening but does not transform the table.
- A sample is more convenient for reviewing a large dataset; “all data” is still subject to the system’s overall limits.
- After changing terminal, check the connections on the canvas.
Configuration example
After Join, add a preview with row_limit=100, terminal=false. Check missing categories and the row count, after which the same data reaches the target.