Why should you care?

Production outages and slow systems are diagnosed with users knowledge — not guesswork.

See it live — copy this example

Run these statements in SQL Developer or SQL*Plus against your lab PDB. Prefer a practice user — not SYS — for application SQL.

CREATE USER app_user IDENTIFIED BY "ChangeMe#1"
  DEFAULT TABLESPACE users
  TEMPORARY TABLESPACE temp
  QUOTA 50M ON users;

GRANT CREATE SESSION, CREATE TABLE TO app_user;

What happened?

• Users need CREATE SESSION to connect and quotas to create objects in a tablespace.
• Follow the steps below — typing the code yourself is the fastest way to learn.

Practice next

1. Connect to your lab as a user with the needed privileges.
2. Run the read-only checks first.
3. Write the definition of this topic in your own words.
4. Change one literal in the example and re-run.
5. Write a second example from memory without looking.

Remember

You can explain Users in plain English. You ran at least one related command or query. You know one real system where it matters.

Users on a banking PDB

On-call DBA reviews users during a health check before peak traffic.

Outcome: You know which view/command to open first.