Performance
Slow SQL: Where Should You Start? 5 Questions Before Adding an Index
Before adding an index, identify the SQL, input values, timing interval and recent changes, then compare both time and row-level results after a change.
All articles
6 articles
DBA
How Do an Oracle Database and an Instance Differ? See the Difference in One Diagram
Separate an Oracle Database's files from an Instance's memory and processes, then compare their status using v$instance and v$database.
DBA
Not Sure Where to Start with Oracle? Pick One Task
Not sure where to start with Oracle? Use three sample orders to practise SQL, then choose database and DBA topics that fit your work.
Backup & Recovery
Check ARCHIVELOG mode before you need to recover
Understand ARCHIVELOG and NOARCHIVELOG, check your database mode, and plan the switch before a recovery incident.
SQL
Auto-increment in Oracle without a trigger: Identity Columns
Use Identity Columns in Oracle 12c and later instead of managing a sequence and trigger. Learn the three generation modes and what to check during migration.
DBA
Oracle STARTUP and SHUTDOWN: what happens at each stage?
Understand NOMOUNT, MOUNT and OPEN, the four shutdown modes, and why SHUTDOWN ABORT requires instance recovery.