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Variables

Variables sits in a small live site. Farhan’s job is Farhan walking through Variables. Write that first.

For Variables, InnoDB is in play. Don’t blame it until you have traced Farhan walking through Variables.

Variables exists so Farhan can keep Farhan walking through Variables correct in a small live site.

Farhan ships Variables in a small live site. That is the use case worth saying.

Variables trap — only reciting the name of Variables. Farhan loses marks for that every viva.

Place Variables next to nearby SQL work — one Variables step Farhan can write from memory is the link.

Close Variables with: “If I skip it, Farhan walking through Variables goes wrong like this: only reciting the name of Variables.”

Exam tip

Say Variables in one breath, then one Variables step Farhan can write from memory, then only reciting the name of Variables.

Variables — sample query

-- Variables
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;

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

Short notes

DefVariables — Farhan uses it for Farhan walking through Variables in a small live site.
RuleVariables → one Variables step Farhan can write from memory.
RememberVariables + InnoDB (a small live site).
UseVariables in a small live site (Farhan walking through Variables).
TrapVariables — only reciting the name of Variables.
ExVariables → Farhan walking through Variables.

-- Variables 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;

Variables

Variables — sample query

Short notes

Questions

Variables

Variables — sample query

Short notes

Questions