Show ERD in settings tab

routes/settings.py

@@ -116,3 +116,92 @@ def toggle_theme():
         # Actually, for HTMX we might want to return something or just 200 OK.
         return "", 200
     return "Invalid theme", 400
+
+@settings.route("/database_schema", methods=["GET"])
+@login_required
+def database_schema():
+    """Display database schema with ERD visualization"""
+    # Fetch database schema information
+    schema_info = get_database_schema()
+    
+    if htmx:
+        return render_block(
+            environment,
+            "dashboard/settings/database_schema.html",
+            "page",
+            schema_info=schema_info
+        )
+    return render_template("dashboard/settings/database_schema.html", schema_info=schema_info)
+
+def get_database_schema():
+    """Fetch database schema information for ERD generation"""
+    # Get all tables
+    tables = db.execute("""
+        SELECT 
+            table_name,
+            COALESCE(obj_description((quote_ident(table_schema)||'.'||quote_ident(table_name))::regclass), '') as table_comment
+        FROM information_schema.tables
+        WHERE table_schema = 'public'
+        AND table_type = 'BASE TABLE'
+        ORDER BY table_name
+    """)
+    
+    schema_data = []
+    
+    for table in tables or []:
+        table_name = table['table_name']
+        
+        # Get columns for this table
+        columns = db.execute("""
+            SELECT 
+                column_name,
+                data_type,
+                is_nullable,
+                column_default,
+                character_maximum_length
+            FROM information_schema.columns
+            WHERE table_schema = 'public'
+            AND table_name = %s
+            ORDER BY ordinal_position
+        """, [table_name])
+        
+        # Get foreign keys for this table
+        foreign_keys = db.execute("""
+            SELECT
+                kcu.column_name,
+                ccu.table_name AS foreign_table_name,
+                ccu.column_name AS foreign_column_name
+            FROM information_schema.table_constraints AS tc
+            JOIN information_schema.key_column_usage AS kcu
+                ON tc.constraint_name = kcu.constraint_name
+                AND tc.table_schema = kcu.table_schema
+            JOIN information_schema.constraint_column_usage AS ccu
+                ON ccu.constraint_name = tc.constraint_name
+                AND ccu.table_schema = tc.table_schema
+            WHERE tc.constraint_type = 'FOREIGN KEY'
+            AND tc.table_name = %s
+            AND tc.table_schema = 'public'
+        """, [table_name])
+        
+        # Get primary keys
+        primary_keys = db.execute("""
+            SELECT kcu.column_name
+            FROM information_schema.table_constraints tc
+            JOIN information_schema.key_column_usage kcu
+                ON tc.constraint_name = kcu.constraint_name
+                AND tc.table_schema = kcu.table_schema
+            WHERE tc.constraint_type = 'PRIMARY KEY'
+            AND tc.table_name = %s
+            AND tc.table_schema = 'public'
+        """, [table_name])
+        
+        pk_columns = [pk['column_name'] for pk in (primary_keys or [])]
+        
+        schema_data.append({
+            'table_name': table_name,
+            'columns': columns or [],
+            'foreign_keys': foreign_keys or [],
+            'primary_keys': pk_columns
+        })
+    
+    return schema_data