Reject impossible maintenance jobs

P99 was registered, but J1 lost its duration

An otherwise readable inspection job points to an absent pump. Protect the relationship and its duration rule together.

BOTIE

The changed fixture supplies the missing parent but gives J1 a null duration. Why should the failing identity change?

The inputs we are comparing

Proposed jobs

One job points to an absent pump

[
  {
    "id": "J1",
    "asset_id": "P7",
    "minutes": 20
  },
  {
    "id": "J2",
    "asset_id": "P99",
    "minutes": 10
  }
]

The parent is added but duration is missing

[
  {
    "id": "J1",
    "asset_id": "P7",
    "minutes": null
  },
  {
    "id": "J2",
    "asset_id": "P99",
    "minutes": 10
  }
]

Registered asset IDs

One job points to an absent pump

The parent is added but duration is missing

0P7
1P99

Result for one job points to an absent pump

Choose an explanation to test

Parent membership now passes, while J1 violates the required-duration ruleOnce every parent exists, every job must be valid

The asset exists but the duration is negative

This check uses the pieces from “Check each job against its parent and duration”.

BOTIE

P2 is registered. J7 proposes minus five minutes and J8 proposes twelve. Predict the rejected IDs.

Proposed jobs: [ { "id": "J7", "asset_id": "P2", "minutes": -5 }, { "id": "J8", "asset_id": "P2", "minutes": 12 } ]
Registered asset IDs: 0P2

What result should your machine produce for this case?

Use a number, text, or an array matching the requested result. For a matrix, put each row in brackets. Saving your prediction runs your current construction on these inputs and checks the earlier examples too.

Build a construction in the workspace above first. This case will test those pieces.

Why does a foreign key not establish which technician is allowed to see the asset?

Your notes for later. These stay with this journey.

Separate data validity from authorisation, and test both at their proper boundaries.

The widget illustrates selected invariants. The SQL table additionally enforces uniqueness and database-level relationships.

Work through the SQL challenges →

Continue the courseWhy Must a Pump Move Be Edited on Every Job? →

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