diff --git a/.jules/bolt.md b/.jules/bolt.md
index f1a8c146..b4838a96 100644
--- a/.jules/bolt.md
+++ b/.jules/bolt.md
@@ -77,3 +77,6 @@ Optimized metric route processing to O(N) by creating a mapping of routes direct
 ## 2024-07-13 - [Optimize Export Dictionary FK lookups]
 **Learning:** Found O(N * C * E) performance bottleneck in ERD export dictionaries due to repeated array searching with `edges.some()` inside a nested loop over nodes and columns.
 **Action:** Replace repeated linear array scans for edges by precomputing O(1) Set lookups of foreign key column handles per node before looping.
+## 2024-07-25 - Avoid redundant handle generation and O(N*C) string searches during ERD export
+**Learning:** ERD export functions (Mermaid, Data Dictionary, DBML, etc.) frequently need to extract column names from edge `sourceHandle` strings. Iterating over all columns in all tables and continuously re-encoding column names with `sourceColumnHandleId` to match against the edge handle is extremely expensive (O(N*C)).
+**Action:** When extracting data from heavily encoded UI identifiers (like React Flow handles), implement an O(1) decoding utility (`parseColumnNameFromHandle`) to parse the string back into its original value directly, rather than encoding every possible value to search for a match.
diff --git a/frontend/src/erd/__tests__/coverageEdges.test.ts b/frontend/src/erd/__tests__/coverageEdges.test.ts
index 0dedc39e..8af6868c 100644
--- a/frontend/src/erd/__tests__/coverageEdges.test.ts
+++ b/frontend/src/erd/__tests__/coverageEdges.test.ts
@@ -50,7 +50,7 @@ describe('coverage edge contracts', () => {
       { id: 'missing', source: 'missing', target: 'parent' },
       { id: 'partial-data', source: 'child', target: 'parent', data: { sourceColumns: ['parent_id'] } },
       { id: 'empty-data', source: 'child', target: 'parent', data: { sourceColumns: [], targetColumns: [] } },
-      { id: 'handles', source: 'child', target: 'parent', sourceHandle: 'src-parent_id', targetHandle: 'tgt-' },
+      { id: 'handles', source: 'child', target: 'parent', sourceHandle: 'src-c-0070-0061-0072-0065-006e-0074-005f-0069-0064', targetHandle: 'tgt-c-empty' },
     ]
 
     const dbml = exportDbml([parent, child, node('empty', '', [])], edges)
diff --git a/frontend/src/erd/__tests__/dbml.test.ts b/frontend/src/erd/__tests__/dbml.test.ts
index 4634f767..c5003793 100644
--- a/frontend/src/erd/__tests__/dbml.test.ts
+++ b/frontend/src/erd/__tests__/dbml.test.ts
@@ -65,8 +65,8 @@ describe('exportDbml', () => {
         id: 'e1',
         source: '2',
         target: '1',
-        sourceHandle: 'src-user_id',
-        targetHandle: 'tgt-id',
+        sourceHandle: 'src-c-0075-0073-0065-0072-005f-0069-0064',
+        targetHandle: 'tgt-c-0069-0064',
         label: 'rel',
       },
     ];
diff --git a/frontend/src/erd/dbml.ts b/frontend/src/erd/dbml.ts
index 4a0c2029..294b7319 100644
--- a/frontend/src/erd/dbml.ts
+++ b/frontend/src/erd/dbml.ts
@@ -1,5 +1,6 @@
 import type { Node, Edge } from "@xyflow/react";
 import type { TableNodeData, ForeignKeyEdgeData } from "./convert";
+import { parseColumnNameFromHandle } from "./handleUtils";
 
 function escapeString(str: string): string {
   return str.replace(/'/g, "''");
@@ -89,8 +90,12 @@ export function exportDbml(
         sourceCols = edgeData.sourceColumns.map(safeId);
         targetCols = edgeData.targetColumns.map(safeId);
       } else if (edge.sourceHandle && edge.targetHandle) {
-         sourceCols = [safeId(edge.sourceHandle.replace('src-', ''))];
-         targetCols = [safeId(edge.targetHandle.replace('tgt-', ''))];
+         const parsedSource = parseColumnNameFromHandle(edge.sourceHandle);
+         const parsedTarget = parseColumnNameFromHandle(edge.targetHandle);
+         if (parsedSource !== null && parsedTarget !== null) {
+           sourceCols = [safeId(parsedSource)];
+           targetCols = [safeId(parsedTarget)];
+         }
       }
 
       if (sourceCols.length > 0 && targetCols.length > 0) {
diff --git a/frontend/src/erd/export.ts b/frontend/src/erd/export.ts
index 62ce7219..75b2730b 100644
--- a/frontend/src/erd/export.ts
+++ b/frontend/src/erd/export.ts
@@ -2,7 +2,7 @@ import type { Node, Edge } from '@xyflow/react';
 import { normalizeBusinessGroupColor } from './businessGroups';
 import type { IndexRecommendation } from './cardinality';
 import type { ForeignKeyEdgeData, TableNodeData } from './convert';
-import { sourceColumnHandleId, targetColumnHandleId } from './handleUtils';
+import { parseColumnNameFromHandle } from './handleUtils';
 
 export * from './exportDataDictionary';
 
@@ -67,14 +67,19 @@ function fkColumnsForEdge(
     return { sourceColumns, targetColumns };
   }
 
-  const sourceHandleColumn = (sourceNode.data.columns || [])
-    .find((column) => sourceColumnHandleId(column.column_name) === edge.sourceHandle)
-    ?.column_name;
-  const targetHandleColumn = (targetNode.data.columns || [])
-    .find((column) => targetColumnHandleId(column.column_name) === edge.targetHandle)
-    ?.column_name;
-  if (sourceHandleColumn && targetHandleColumn) {
-    return { sourceColumns: [sourceHandleColumn], targetColumns: [targetHandleColumn] };
+  const parsedSource = parseColumnNameFromHandle(edge.sourceHandle);
+  const parsedTarget = parseColumnNameFromHandle(edge.targetHandle);
+
+  if (parsedSource && parsedTarget) {
+    const sourceHandleColumn = (sourceNode.data.columns || [])
+      .find((column) => column.column_name === parsedSource)
+      ?.column_name;
+    const targetHandleColumn = (targetNode.data.columns || [])
+      .find((column) => column.column_name === parsedTarget)
+      ?.column_name;
+    if (sourceHandleColumn && targetHandleColumn) {
+      return { sourceColumns: [sourceHandleColumn], targetColumns: [targetHandleColumn] };
+    }
   }
 
   const fallbackSource = (sourceNode.data.columns || [])
diff --git a/frontend/src/erd/exportDataDictionary.ts b/frontend/src/erd/exportDataDictionary.ts
index 0111660d..be53720f 100644
--- a/frontend/src/erd/exportDataDictionary.ts
+++ b/frontend/src/erd/exportDataDictionary.ts
@@ -1,7 +1,7 @@
 import type { Edge, Node } from '@xyflow/react';
 
 import type { ForeignKeyEdgeData, TableNodeData } from './convert';
-import { sourceColumnHandleId } from './handleUtils';
+import { parseColumnNameFromHandle, sourceColumnHandleId } from './handleUtils';
 
 const CONTROL_TEXT_RE = /[\u0000-\u001f\u007f]+/g;
 const CSV_FORMULA_RE = /^[=+\-@]/;
@@ -41,7 +41,6 @@ function sourceColumnsForEdge(edge: Edge): Set<string> {
 
 type ForeignKeyNodeInfo = {
   columns: Set<string>;
-  handles: Set<string>;
 };
 
 function foreignKeyColumnsByNode(edges: Edge[]): Map<string, ForeignKeyNodeInfo> {
@@ -50,7 +49,7 @@ function foreignKeyColumnsByNode(edges: Edge[]): Map<string, ForeignKeyNodeInfo>
   for (const edge of edges) {
     let info = map.get(edge.source);
     if (!info) {
-      info = { columns: new Set<string>(), handles: new Set<string>() };
+      info = { columns: new Set<string>() };
       map.set(edge.source, info);
     }
 
@@ -59,7 +58,10 @@ function foreignKeyColumnsByNode(edges: Edge[]): Map<string, ForeignKeyNodeInfo>
     }
 
     if (edge.sourceHandle) {
-      info.handles.add(edge.sourceHandle);
+      const parsedColumn = parseColumnNameFromHandle(edge.sourceHandle);
+      if (parsedColumn) {
+        info.columns.add(parsedColumn);
+      }
     }
   }
 
@@ -74,12 +76,7 @@ function isForeignKeyColumn(
   const info = edgeColumnsByNode.get(node.id);
   if (!info) return false;
 
-  if (info.columns.has(columnName)) {
-    return true;
-  }
-
-  const handleId = sourceColumnHandleId(columnName);
-  return info.handles.has(handleId);
+  return info.columns.has(columnName);
 }
 
 function exampleValue(value: TableNodeData['columns'][number]['example_value']): string {
diff --git a/frontend/src/erd/handleUtils.test.ts b/frontend/src/erd/handleUtils.test.ts
index 0278739e..b6543047 100644
--- a/frontend/src/erd/handleUtils.test.ts
+++ b/frontend/src/erd/handleUtils.test.ts
@@ -1,7 +1,39 @@
 import { describe, it, expect } from 'vitest';
-import { sanitizeHandleId, sourceColumnHandleId, targetColumnHandleId } from './handleUtils';
+import { parseColumnNameFromHandle, sanitizeHandleId, sourceColumnHandleId, targetColumnHandleId } from './handleUtils';
 
 describe('handleUtils', () => {
+  describe('parseColumnNameFromHandle', () => {
+    it('should return null for invalid handles', () => {
+      expect(parseColumnNameFromHandle(null)).toBeNull();
+      expect(parseColumnNameFromHandle(undefined)).toBeNull();
+      expect(parseColumnNameFromHandle('')).toBeNull();
+      expect(parseColumnNameFromHandle('invalid-handle')).toBeNull();
+    });
+
+    it('should decode a simple ascii string handle', () => {
+      expect(parseColumnNameFromHandle('c-0069-0064')).toBe('id');
+      expect(parseColumnNameFromHandle('src-c-0069-0064')).toBe('id');
+      expect(parseColumnNameFromHandle('tgt-c-0069-0064')).toBe('id');
+    });
+
+    it('should decode an empty string handle', () => {
+      expect(parseColumnNameFromHandle('c-empty')).toBe('');
+      expect(parseColumnNameFromHandle('src-c-empty')).toBe('');
+    });
+
+    it('should decode special characters handle', () => {
+      expect(parseColumnNameFromHandle('c-0075-0073-0065-0072-005f-0069-0064')).toBe('user_id');
+    });
+
+    it('should decode unicode characters handle', () => {
+      expect(parseColumnNameFromHandle('c-0069-0064-005f-ac00')).toBe('id_가');
+    });
+
+    it('should decode emojis handle', () => {
+      expect(parseColumnNameFromHandle('c-0069-0064-005f-1f680')).toBe('id_🚀');
+    });
+  });
+
   describe('sanitizeHandleId', () => {
     it('should encode a simple ascii string', () => {
       expect(sanitizeHandleId('id')).toBe('c-0069-0064');
diff --git a/frontend/src/erd/handleUtils.ts b/frontend/src/erd/handleUtils.ts
index 054d5ab2..2961024e 100644
--- a/frontend/src/erd/handleUtils.ts
+++ b/frontend/src/erd/handleUtils.ts
@@ -1,3 +1,12 @@
+export function parseColumnNameFromHandle(handleId: string | null | undefined): string | null {
+  if (!handleId) return null;
+  const match = handleId.match(/^(?:src-|tgt-)?c-(.+)$/);
+  if (!match) return null;
+  const encoded = match[1];
+  if (encoded === 'empty') return '';
+  return encoded.split('-').map(hex => String.fromCodePoint(parseInt(hex, 16))).join('');
+}
+
 export function sanitizeHandleId(columnName: string): string {
   const encoded = Array.from(columnName, (char) => {
     // Array.from only yields non-empty Unicode scalars, so codePointAt(0) is defined.
diff --git a/frontend/src/erd/mermaid.ts b/frontend/src/erd/mermaid.ts
index 6e77a9bc..62816322 100644
--- a/frontend/src/erd/mermaid.ts
+++ b/frontend/src/erd/mermaid.ts
@@ -1,6 +1,6 @@
 import type { Node, Edge } from "@xyflow/react";
 import type { TableNodeData } from "./convert";
-import { sanitizeHandleId } from "./handleUtils";
+import { parseColumnNameFromHandle, sanitizeHandleId } from "./handleUtils";
 
 function sanitizeString(str: string): string {
   if (!str) return "";
@@ -29,14 +29,20 @@ export function exportMermaid(
   const fkNodesWithoutHandles = new Set<string>();
 
   for (const edge of edges) {
-    if (edge.sourceHandle?.startsWith("src-")) {
-      fkNodeColumnPairs.add(`${edge.source}:${edge.sourceHandle.slice(4)}`);
-    } else if (!edge.sourceHandle) {
+    if (edge.sourceHandle) {
+      const parsedSource = parseColumnNameFromHandle(edge.sourceHandle);
+      if (parsedSource) {
+        fkNodeColumnPairs.add(`${edge.source}:${parsedSource}`);
+      }
+    } else {
       fkNodesWithoutHandles.add(edge.source);
     }
 
-    if (edge.targetHandle?.startsWith("tgt-")) {
-      fkNodeColumnPairs.add(`${edge.target}:${edge.targetHandle.slice(4)}`);
+    if (edge.targetHandle) {
+      const parsedTarget = parseColumnNameFromHandle(edge.targetHandle);
+      if (parsedTarget) {
+        fkNodeColumnPairs.add(`${edge.target}:${parsedTarget}`);
+      }
     }
   }
 
@@ -48,10 +54,9 @@ export function exportMermaid(
       let modifiers = "";
       if (col.is_pk) modifiers += " PK";
 
-      const safeId = sanitizeHandleId(col.column_name);
       // ⚡ Bolt: O(1) lookups instead of O(E) array search for every column
       const isFk =
-        fkNodeColumnPairs.has(`${node.id}:${safeId}`) ||
+        fkNodeColumnPairs.has(`${node.id}:${col.column_name}`) ||
         (fkNodesWithoutHandles.has(node.id) && node.data.badges?.fk);
 
       if (isFk && !col.is_pk) modifiers += " FK";