Database Changes SQL Topic exerciseEasyVerified answerSQLite + PostgreSQL live · 3 guided

Create an Account Notes Table

Create account_notes with note_id, account_id, note_text, and created_at.

  • Table creation
  • Keys and constraints

Exercise brief

Understand the request

Support platform team Account notes require a stable identifier, a valid account relationship, the note text, and its business date.

Support teams need a governed place to attach dated notes to customer accounts.

Return

  • Create four columns with the requested keys, types, and nullability.

Constraints

  • Make note_id the primary key.
  • Reference accounts(account_id).
  • Make account_id, note_text, and created_at required.

Data you will use

Review the relevant tables before deciding how to join, filter, or aggregate them.

accounts

  • account_idINTEGER

Hints, when you need them

Open one clue at a time so you still do the reasoning.

Hint 1

Define the table and its integrity rules together with CREATE TABLE.

Hint 2

Use PRIMARY KEY for note_id and REFERENCES accounts(account_id) for the relationship.

Hint 3

CREATE TABLE account_notes (note_id INTEGER PRIMARY KEY, account_id INTEGER NOT NULL REFERENCES accounts(account_id), ...);

Verified SQL answer

Attempt the problem first, then compare structure and reasoning—not just syntax.

Reveal solution and explanation
CREATE TABLE account_notes (
  note_id INTEGER PRIMARY KEY,
  account_id INTEGER NOT NULL REFERENCES accounts(account_id),
  note_text VARCHAR(200) NOT NULL,
  created_at DATE NOT NULL
);

Why this works

Keys and NOT NULL constraints turn the business rules into database-enforced guarantees instead of application conventions.

Success check

The table has exactly four columns and a foreign key from account_id to accounts.

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