SQL · Theory

Database vs Schema

Theory

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Database vs Schema

Database vs Schema sits in a first job task. Farhan’s job is a Database vs Schema dry-run. Write that first.

Do Database vs Schema once by hand. one Database vs Schema step Farhan can write from memory. Change one input. Say the new result out loud.

Without Database vs Schema, a first job task gets messy and a Database vs Schema dry-run is hard to trust.

Use Database vs Schema when a Database vs Schema dry-run must stay clear. If a simpler SQL step works, use that instead.

If a Database vs Schema dry-run breaks under Database vs Schema, check copy-pasting Database vs Schema without a dry-run first.

Database vs Schema is not a lonely heading. Farhan ties it to a Database vs Schema dry-run.

Close Database vs Schema with: “If I skip it, a Database vs Schema dry-run goes wrong like this: copy-pasting Database vs Schema without a dry-run.”

Exam tip

Say Database vs Schema in one breath, then one Database vs Schema step Farhan can write from memory, then copy-pasting Database vs Schema without a dry-run.

Database vs Schema — sample query

-- Database vs Schema
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;

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

Short notes

DefDatabase vs Schema — Farhan uses it for a Database vs Schema dry-run in a first job task.
RuleDatabase vs Schema → one Database vs Schema step Farhan can write from memory.
RememberDatabase vs Schema + an index (a first job task).
UseDatabase vs Schema in a first job task (a Database vs Schema dry-run).
TrapDatabase vs Schema — copy-pasting Database vs Schema without a dry-run.
ExDatabase vs Schema → a Database vs Schema dry-run.

-- Database vs Schema 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;

Database vs Schema

Database vs Schema — sample query

Short notes

Questions

Database vs Schema

Database vs Schema — sample query

Short notes

Questions