=== PostgreSQL PDO Connection Examples ===

Example 1: Singleton Pattern
----------------------------
Singleton connection works!

Example 2: Helper Function (Recommended)
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Connected to database: frcsdb as user: taf

Example 3: Prepared Statements
------------------------------
Number of tables in public schema: 446

Example 4: Transaction Example
------------------------------
Transaction test value: 1
Transaction committed successfully

Example 5: Error Handling
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Caught expected error: SQLSTATE[42P01]: Undefined table: 7 ERROR:  relati...
Error handling works correctly!

Example 6: Schema Information
-----------------------------
Sample tables in the database:
  - account_ai_feedback (owner: taf)
  - appeals (owner: taf)
  - applications (owner: taf)
  - appraisal_templates (owner: taf)
  - attendance (owner: taf)

Example 7: Different Fetch Methods
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Database name (fetchColumn): frcsdb
Single row (fetch): DB=frcsdb, User=taf
Multiple rows (fetchAll): row1, row2

=== Quick Usage Summary ===
1. Simple query:     $pdo = getDb(); $result = $pdo->query('SELECT ...');
2. Prepared query:   $stmt = $pdo->prepare('SELECT * FROM table WHERE id = ?'); $stmt->execute([$id]);
3. Insert/Update:    $stmt = $pdo->prepare('INSERT INTO table VALUES (?, ?)'); $stmt->execute([$val1, $val2]);
4. Transaction:      $pdo->beginTransaction(); /* operations */ $pdo->commit();
5. Test connection:  if (testDbConnection()) { /* proceed */ }