SQL · Theory

Create Trigger

Theory

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Create Trigger

Zara only reaches for Create Trigger when a Create Trigger dry-run has to stay correct in a first job task.

Create Trigger order: meaning → one Create Trigger step Zara can write from memory → one limit. Dumping ten features helps nobody.

Create Trigger exists so Zara can keep a Create Trigger dry-run correct in a first job task.

Zara ships Create Trigger in a first job task. That is the use case worth saying.

If a Create Trigger dry-run breaks under Create Trigger, check skipping the failure case for Create Trigger first.

After Create Trigger, Zara should still remember skipping the failure case for Create Trigger.

Close Create Trigger with: “If I skip it, a Create Trigger dry-run goes wrong like this: skipping the failure case for Create Trigger.”

Exam tip

Say Create Trigger in one breath, then one Create Trigger step Zara can write from memory, then skipping the failure case for Create Trigger.

Create Trigger — sample query

-- Create Trigger
CREATE TABLE demo (
  id INTEGER PRIMARY KEY,
  label TEXT NOT NULL,
  qty INTEGER DEFAULT 0
);
INSERT INTO demo (id, label, qty) VALUES
  (1, 'alpha', 2),
  (2, 'beta', 5);
SELECT label, qty FROM demo WHERE qty >= 2 ORDER BY qty DESC;

Create Trigger: create two demo rows, then SELECT qty >= 2 ordered. Say which labels come back.

Short notes

DefCreate Trigger — Zara uses it for a Create Trigger dry-run in a first job task.
RuleCreate Trigger → one Create Trigger step Zara can write from memory.
RememberCreate Trigger + an index (a first job task).
UseCreate Trigger in a first job task (a Create Trigger dry-run).
TrapCreate Trigger — skipping the failure case for Create Trigger.
ExCreate Trigger → a Create Trigger dry-run.

-- Create Trigger CREATE TABLE demo ( id INTEGER PRIMARY KEY, label TEXT NOT NULL, qty INTEGER DEFAULT 0 ); INSERT INTO demo (id, label, qty) VALUES (1, 'alpha', 2), (2, 'beta', 5); SELECT label, qty FROM demo WHERE qty >= 2 ORDER BY qty DESC;

Create Trigger

Create Trigger — sample query

Short notes

Questions

Create Trigger

Create Trigger — sample query

Short notes

Questions