Pro ยท Lesson 6 of 11

Task settings, mappings, and transforms

Table mappings are JSON selection rules. Transformations rename or drop columns. Task settings choose LOB mode, history, and validation. The defaults are not a design.

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Picture it this way

The mapping is the list of boxes allowed on the truck. A transformation is a label maker that renames a box on the way. Task settings are the truck's rules: how heavy a box may be, and whether someone counts the boxes at the other end.

Selection rules

A selection rule includes or excludes a schema and a table. Rules run in order. A later exclude can remove what an earlier include added. Wildcards are convenient and dangerous. public.% on a PostgreSQL source will take tables you forgot, including ones the application still writes.

Start with an explicit include list for the first test. Widen it when the test is boring.

Transformations

A transformation can rename a schema, rename a table, rename or remove a column, or change case. It does not translate a stored procedure. That is schema conversion.

Adding a column with a transformation is a small, explicit change. Doing business logic in a DMS expression is how the migration becomes an untested program. Prefer a later SQL step you can review.

Knob If you leave the default
Table mapping You might move every table the wildcard matches
LOB mode You might truncate or slow the load
Target table prep You might drop and recreate target tables
Validation You might not notice a missed row

Rules, then rows

  1. Include
  2. Exclude
  3. Tables

Step 1 of 3Include names the tables that may move.

Lab: include two tables and exclude a third

This JSON is the shape of a selection. Replace the names. Do not start a task until the endpoint test from the earlier lesson is green.

{
  "rules": [
    {
      "rule-type": "selection",
      "rule-id": "1",
      "rule-name": "include-orders",
      "object-locator": {"schema-name": "shop", "table-name": "orders"},
      "rule-action": "include"
    },
    {
      "rule-type": "selection",
      "rule-id": "2",
      "rule-name": "include-customers",
      "object-locator": {"schema-name": "shop", "table-name": "customers"},
      "rule-action": "include"
    }
  ]
}

Concept summary

Knowledge check

Two rules include a schema and then exclude one table. Which table moves?

A transformation renames a column. What did it not do?

Why avoid a wildcard on the first test?

Official sources

Checked against the linked documentation in October 2026. A later release can move a flag, a price, or a supported pair. Use the page for the version you installed.