| Q |
What is "Subset by Example" and when should I use it? |
| A |
Defining an extraction model manually requires knowledge
of the data model and careful crafting of SQL restriction
conditions. Subset by
Example removes that burden: you use the Data Browser
to navigate to the exact rows you want to export, then ask
Jailer to turn that browsing session into a reusable
extraction model.
It is the right approach when:
- You want to export data that you can easily identify
by browsing — a specific customer, an order, a
test dataset — rather than by writing a WHERE
clause.
- You want to create a first working model quickly and
then refine it in the Extraction Model Editor.
- You need a one-off export and do not want to maintain
a permanent extraction model.
|
| Q |
How do I invoke the feature? |
| A |
Open the Data Browser and navigate to the subject table
and its related tables. When you are satisfied with the data
you see, right-click the subject table panel and choose one
of:
| Create Extraction Model |
Generates a .jm
model file and opens it in the Extraction Model Editor
so you can inspect or further refine it before
exporting. |
| Export Data from here |
Generates the model internally and opens the export
dialog immediately — the Extraction Model Editor
is bypassed for a faster one-step export. |
|
| Q |
What data does Jailer use to build the model? |
| A |
Jailer analyses only the associations you actually
navigated during your browsing session. For each table panel
you opened in the Data Browser, the rows currently visible in
that panel — including any active column filters —
become the restriction condition for that association.
An association that was never followed may still be restricted:
if one of its tables is visible in the browser but the other
is not, the association is restricted in that direction.
If neither table of an association was navigated to, that
association is irrelevant for the result and does not affect
the export. This means the model is as specific as your
browsing was: the more precisely you navigated, the tighter
the resulting restrictions.
|
| Q |
What is the "Include parent tables" option? |
| A |
When Jailer detects parent tables (tables referenced by
a foreign key of the subject or an associated table) that
were not explicitly browsed, it warns you in the confirmation
dialog and highlights those tables in red.
| Checked (default) |
Parent table associations are included in the
model. The export will follow those foreign keys and
include the referenced parent rows, keeping referential
integrity intact. |
| Unchecked |
Parent table restrictions are removed from the
model. Use this when you intentionally want to export
rows without their parent rows, for example because
the parent data already exists at the target. |
|
| Q |
Where is the generated extraction model saved? |
| A |
The model is saved as a
.jm file under
extractionmodel/by-example/SbE-<TableName>-<Timestamp>.jm
The timestamp ensures each session produces a uniquely named
file. You can rename or move the file afterwards; the content
is independent of the filename.
|
| Q |
Can I refine the generated model before exporting? |
| A |
Yes, if you chose
Create Extraction Model.
The generated model opens in the Extraction Model Editor,
where you can:
- Review and edit restriction conditions for individual
associations.
- Enable or disable additional associations that were not
browsed.
- Add further subject tables or adjust the subject
condition.
- Save the model under a different name for later
reuse.
If you chose Export Data
from here, the model is generated and the export dialog
opens directly without showing the editor. You can still open
the saved .jm file
later to review or modify it.
|
| Q |
What are the limitations of Subset by Example? |
| A |
The main limitation is that the feature derives
restrictions only from associations you actually navigated
in the Data Browser. An association is also restricted when
one of its tables was visible but the other was not (in that
direction). If neither table of an association was navigated
to, that association is irrelevant for the result and does
not affect the export. Always review
the generated model in the Extraction Model Editor —
particularly the
Closure view —
to check which tables are reachable and tighten any
unintended unrestricted associations.
Additionally, the model reflects the state of the Data
Browser at the moment the feature was invoked. If the
underlying data changes, you may need to regenerate or
manually update the restriction conditions.
|
