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SQL

Publish both sides of a stock transfer

Twelve seals are requested from a store holding ten

A transfer changes two store balances. Reject an impossible transfer without publishing only half of its changes.

BOTIE

The staged source balance is negative. Which state should the construction publish under this lesson’s rule?
The inputs we are comparing

Current store balances

Same in both cases

[
  {
    "id": "north",
    "units": 10
  },
  {
    "id": "south",
    "units": 2
  }
]

Proposed changes by store

Transfer three seals

{
  "north": -3,
  "south": 3
}

The source cannot supply twelve

{
  "north": -12,
  "south": 12
}
Result for transfer three seals
[
  {
    "id": "north",
    "units": 7
  },
  {
    "id": "south",
    "units": 5
  }
]
Choose an explanation to test
The transfer uses every remaining source part

This check uses the pieces from “Choose one complete inventory state”.

BOTIE

West holds four units and east holds one. The proposed transfer moves all four west units east. Predict whether a zero source balance passes and which full state is published.
Current store balances
[
  {
    "id": "west",
    "units": 4
  },
  {
    "id": "east",
    "units": 1
  }
]
Proposed changes by store
{
  "west": -4,
  "east": 4
}

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.

Which effects would a SQL rollback fail to undo if the program had already sent a delivery notification?

A database transaction has a boundary. Effects outside it need their own recovery design.

This is an atomic-choice teaching model. It does not simulate disk persistence, locks or the database transaction log.

Work through the SQL challenges →
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