Unexpected quines can appear when querying tables like V$SQL. To avoid them you must sometimes add an extra predicate to those queries:

Entity-Attribute-Value (EAV) models are a contentious topic in database design.  Flexibility is important but some things should not be sacrificed.

On the surface both performance tuning and debugging follow the same process: find a problem, drill down to the root cause, then fix or work around the underlying problem.

Use these slightly unusual styles to reduce the complexity of SQL code:

Combine the alternative quoting mechanism and templates to dramatically improve code readability compared to simple string concatenation.

The primary languages of Oracle databases are SQL and PL/SQL. Despite what many official sources claim, Java in the database is a distant third and should be avoided when possible.