DBS-C01 Deployment and Migration Practice Question

Exhibit

Refer to the exhibit.

-- AWS DMS Migration Task JSON excerpt:
{
  "MigrationType": "full-load",
  "TableMappings": {
    "rules": [
      {
        "rule-type": "selection",
        "rule-id": "1",
        "rule-name": "1",
        "object-locator": {
          "schema-name": "%",
          "table-name": "%"
        },
        "rule-action": "include"
      }
    ]
  },
  "TargetTablePrepMode": "DROP_AND_CREATE"
}

A team is using AWS DMS to migrate a 3 TB Oracle database to Amazon Aurora PostgreSQL. They configured the task as shown. After the full load completes, they notice that the target tables have no indexes, primary keys, or foreign keys. What is the most likely cause?

⚠ Common exam trap

A common mix-up: candidates assume DMS automatically replicates all schema objects, including indexes and constraints, when in fact DMS only migrates table structure and data, leaving schema objects like indexes and foreign keys to be handled separately.

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

The TargetTablePrepMode is set to DROP_AND_CREATE, which creates tables without indexes or constraints.

When TargetTablePrepMode is set to DROP_AND_CREATE, AWS DMS drops the target table if it exists and then creates a new one using only the basic column definitions from the source. It does not migrate indexes, primary keys, or foreign keys because DMS is not designed to replicate schema objects beyond table structure and data. To preserve constraints and indexes, you must either pre-create them on the target or use a different prep mode like TRUNCATE_BEFORE_LOAD.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✗
The migration task did not include transformation rules to create indexes and constraints.
Why it's wrong here
Transformation rules can add metadata but are not required; the issue is with the default behavior of DROP_AND_CREATE.
✗
The table selection rule uses wildcards and excludes system tables, which also excludes index definitions.
Why it's wrong here
Table selection rules filter tables but do not affect index creation on included tables.
✓
The TargetTablePrepMode is set to DROP_AND_CREATE, which creates tables without indexes or constraints.
Why this is correct
DROP_AND_CREATE mode creates target tables with only the column definitions, not indexes or constraints.
✗
The task is using a full load without LOB support, which prevents index creation.
Why it's wrong here
LOB support does not affect index creation.

Go deeper

DBS-C01 Deployment and Migration Practice Question

Exhibit

Why each option matters

Option-by-option breakdown

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