How to Show or Hide Fields Based on Another Item's Value in Oracle APEX
Show company fields only for company customers with a dynamic action, and keep the server side consistent with validations and a process.
AI-Assisted
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How to Create Cascading Select Lists (Parent-Child LOVs) in Oracle APEX
Build country, state, and city select lists that filter each other in Oracle APEX, using the Cascading List of Values settings.
How to Find Performance Problems with Active Session History (ASH)
Analyze a finished workload with V$ACTIVE_SESSION_HISTORY: time on CPU and waits, the top SQL, and who blocked whom, after the fact.
How to Find Blocking Sessions in Oracle
Build a three-session blocking chain, find its root blocker, the locks, and the exact row being waited for, and resolve the block.
How to Find What an Oracle Session Is Waiting For
Read a session's state, wait event, and blocking session in V$SESSION, find its statement, and total its waits with V$SESSION_EVENT.
How to Create a SQL Monitor Report in Oracle
Monitor a long-running query, find it in V$SQL_MONITOR, and read its SQL Monitor report as text and as an HTML page.
How to Use Direct-Path INSERT in Oracle
Compare conventional and direct-path inserts of 500,000 rows by time, redo, and undo, and see when the APPEND hint really pays off.
How to Reduce Hard Parsing with Bind Variables
Measure hard parses, time, and shared pool memory for literal SQL and bind variables, and see what CURSOR_SHARING = FORCE changes.
How Bind Variables Affect Execution Plans: Bind Peeking and Adaptive Cursor Sharing
Watch bind peeking and adaptive cursor sharing on a skewed column, read the child cursors in V$SQL, and see when the first plan sticks.
How to Use Optimizer Hints in Oracle
Write optimizer hints that work, find the ones Oracle ignores with the Hint Report, and see why forcing a plan can make queries slower.
How to Use Extended Statistics for Correlated Columns in Oracle
See how correlated columns fool the optimizer, create a column group with DBMS_STATS, and make sure the optimizer really uses it.
How to Find and Fix Stale Statistics in Oracle
See how stale statistics mislead the optimizer on new data, find stale and missing statistics, and gather them again with DBMS_STATS.
How to Use Histograms for Skewed Data in Oracle
See how skewed data fools the optimizer without histograms, how SIZE AUTO creates them, and how frequency and hybrid histograms fix plans.
How to Find Unused Indexes with DBA_INDEX_USAGE
Read index usage from DBA_INDEX_USAGE, see why sampled tracking can miss rare uses, and remove unused indexes safely.
Why Oracle Is Not Using Your Index
Six common reasons Oracle does a full scan despite an index, each shown in a real plan with the change that makes the index work.
How to Find Slow SQL Statements with V$SQL and V$SQLSTATS
Rank SQL statements by total and per-execution time with V$SQLSTATS, read child cursors in V$SQL, and show the top statement's plan.
How to Read Join Methods in Oracle Execution Plans: Nested Loops, Hash Join, and Merge Join
See nested loops, hash joins and sort-merge joins in real Oracle plans, learn when each is chosen, and compare their cost on one query.
How to Read Table and Index Access Paths in Oracle Execution Plans
See every common Oracle access path in a real plan, learn when the optimizer picks it, and why a full scan is sometimes faster than an index.