diff --git a/tests/integration/database/performance.test.ts b/tests/integration/database/performance.test.ts
new file mode 100644
index 0000000..878273f
--- /dev/null
+++ b/tests/integration/database/performance.test.ts
@@ -0,0 +1,421 @@
+import { describe, it, expect, beforeEach, afterEach } from '@jest/globals';
+import * as Database from 'better-sqlite3';
+import { NodeRepository } from '../../../src/database/node-repository';
+import { TemplateRepository } from '../../../src/templates/template-repository';
+import { DatabaseAdapter } from '../../../src/database/database-adapter';
+import { TestDatabase, TestDataGenerator, PerformanceMonitor } from './test-utils';
+import { ParsedNode } from '../../../src/parsers/node-parser';
+
+describe('Database Performance Tests', () => {
+  let testDb: TestDatabase;
+  let db: Database;
+  let nodeRepo: NodeRepository;
+  let templateRepo: TemplateRepository;
+  let adapter: DatabaseAdapter;
+  let monitor: PerformanceMonitor;
+
+  beforeEach(async () => {
+    testDb = new TestDatabase({ mode: 'file', name: 'performance-test.db', enableFTS5: true });
+    db = await testDb.initialize();
+    adapter = new DatabaseAdapter(db);
+    nodeRepo = new NodeRepository(adapter);
+    templateRepo = new TemplateRepository(adapter);
+    monitor = new PerformanceMonitor();
+  });
+
+  afterEach(async () => {
+    monitor.clear();
+    await testDb.cleanup();
+  });
+
+  describe('Node Repository Performance', () => {
+    it('should handle bulk inserts efficiently', () => {
+      const nodeCounts = [100, 1000, 5000];
+      
+      nodeCounts.forEach(count => {
+        const nodes = generateNodes(count);
+        
+        const stop = monitor.start(`insert_${count}_nodes`);
+        const transaction = db.transaction((nodes: ParsedNode[]) => {
+          nodes.forEach(node => nodeRepo.saveNode(node));
+        });
+        transaction(nodes);
+        stop();
+      });
+
+      // Check performance metrics
+      const stats100 = monitor.getStats('insert_100_nodes');
+      const stats1000 = monitor.getStats('insert_1000_nodes');
+      const stats5000 = monitor.getStats('insert_5000_nodes');
+
+      expect(stats100!.average).toBeLessThan(100); // 100 nodes in under 100ms
+      expect(stats1000!.average).toBeLessThan(500); // 1000 nodes in under 500ms
+      expect(stats5000!.average).toBeLessThan(2000); // 5000 nodes in under 2s
+
+      // Performance should scale sub-linearly
+      const ratio1000to100 = stats1000!.average / stats100!.average;
+      const ratio5000to1000 = stats5000!.average / stats1000!.average;
+      expect(ratio1000to100).toBeLessThan(10); // Should be better than linear scaling
+      expect(ratio5000to1000).toBeLessThan(5);
+    });
+
+    it('should search nodes quickly with indexes', () => {
+      // Insert test data
+      const nodes = generateNodes(10000);
+      const transaction = db.transaction((nodes: ParsedNode[]) => {
+        nodes.forEach(node => nodeRepo.saveNode(node));
+      });
+      transaction(nodes);
+
+      // Test different search scenarios
+      const searchTests = [
+        { query: 'webhook', mode: 'OR' as const },
+        { query: 'http request', mode: 'AND' as const },
+        { query: 'automation data', mode: 'OR' as const },
+        { query: 'HTT', mode: 'FUZZY' as const }
+      ];
+
+      searchTests.forEach(test => {
+        const stop = monitor.start(`search_${test.query}_${test.mode}`);
+        const results = nodeRepo.searchNodes(test.query, test.mode, 100);
+        stop();
+        
+        expect(results.length).toBeGreaterThan(0);
+      });
+
+      // All searches should be fast
+      searchTests.forEach(test => {
+        const stats = monitor.getStats(`search_${test.query}_${test.mode}`);
+        expect(stats!.average).toBeLessThan(50); // Each search under 50ms
+      });
+    });
+
+    it('should handle concurrent reads efficiently', () => {
+      // Insert initial data
+      const nodes = generateNodes(1000);
+      const transaction = db.transaction((nodes: ParsedNode[]) => {
+        nodes.forEach(node => nodeRepo.saveNode(node));
+      });
+      transaction(nodes);
+
+      // Simulate concurrent reads
+      const readOperations = 100;
+      const promises: Promise<any>[] = [];
+
+      const stop = monitor.start('concurrent_reads');
+      
+      for (let i = 0; i < readOperations; i++) {
+        promises.push(
+          Promise.resolve(nodeRepo.getNode(`n8n-nodes-base.node${i % 1000}`))
+        );
+      }
+
+      Promise.all(promises);
+      stop();
+
+      const stats = monitor.getStats('concurrent_reads');
+      expect(stats!.average).toBeLessThan(100); // 100 reads in under 100ms
+      
+      // Average per read should be very low
+      const avgPerRead = stats!.average / readOperations;
+      expect(avgPerRead).toBeLessThan(1); // Less than 1ms per read
+    });
+  });
+
+  describe('Template Repository Performance with FTS5', () => {
+    it('should perform FTS5 searches efficiently', () => {
+      // Insert templates with varied content
+      const templates = Array.from({ length: 10000 }, (_, i) => ({
+        id: i + 1,
+        name: `${['Webhook', 'HTTP', 'Automation', 'Data Processing'][i % 4]} Workflow ${i}`,
+        description: generateDescription(i),
+        workflow: {
+          nodes: [
+            {
+              id: 'node1',
+              name: 'Start',
+              type: ['n8n-nodes-base.webhook', 'n8n-nodes-base.httpRequest', 'n8n-nodes-base.set'][i % 3],
+              typeVersion: 1,
+              position: [100, 100],
+              parameters: {}
+            }
+          ],
+          connections: {},
+          settings: {}
+        },
+        user: { username: 'user' },
+        views: Math.floor(Math.random() * 1000),
+        totalViews: Math.floor(Math.random() * 1000),
+        createdAt: new Date().toISOString(),
+        updatedAt: new Date().toISOString()
+      }));
+
+      const stop1 = monitor.start('insert_templates_with_fts');
+      const transaction = db.transaction((templates: any[]) => {
+        templates.forEach(t => templateRepo.saveTemplate(t));
+      });
+      transaction(templates);
+      stop1();
+
+      // Test various FTS5 searches
+      const searchTests = [
+        'webhook',
+        'data processing',
+        'automat*',
+        '"HTTP Workflow"',
+        'webhook OR http',
+        'processing NOT webhook'
+      ];
+
+      searchTests.forEach(query => {
+        const stop = monitor.start(`fts5_search_${query}`);
+        const results = templateRepo.searchTemplates(query, 100);
+        stop();
+        
+        expect(results.length).toBeGreaterThan(0);
+      });
+
+      // All FTS5 searches should be very fast
+      searchTests.forEach(query => {
+        const stats = monitor.getStats(`fts5_search_${query}`);
+        expect(stats!.average).toBeLessThan(20); // FTS5 searches under 20ms
+      });
+    });
+
+    it('should handle complex node type searches efficiently', () => {
+      // Insert templates with various node combinations
+      const nodeTypes = [
+        'n8n-nodes-base.webhook',
+        'n8n-nodes-base.httpRequest',
+        'n8n-nodes-base.slack',
+        'n8n-nodes-base.googleSheets',
+        'n8n-nodes-base.mongodb'
+      ];
+
+      const templates = Array.from({ length: 5000 }, (_, i) => ({
+        id: i + 1,
+        name: `Template ${i}`,
+        workflow: {
+          nodes: Array.from({ length: 3 }, (_, j) => ({
+            id: `node${j}`,
+            name: `Node ${j}`,
+            type: nodeTypes[(i + j) % nodeTypes.length],
+            typeVersion: 1,
+            position: [100 * j, 100],
+            parameters: {}
+          })),
+          connections: {},
+          settings: {}
+        },
+        user: { username: 'user' },
+        views: 100,
+        totalViews: 100,
+        createdAt: new Date().toISOString(),
+        updatedAt: new Date().toISOString()
+      }));
+
+      const insertTransaction = db.transaction((templates: any[]) => {
+        templates.forEach(t => templateRepo.saveTemplate(t));
+      });
+      insertTransaction(templates);
+
+      // Test searching by node types
+      const stop = monitor.start('search_by_node_types');
+      const results = templateRepo.getTemplatesByNodeTypes([
+        'n8n-nodes-base.webhook',
+        'n8n-nodes-base.slack'
+      ], 100);
+      stop();
+
+      expect(results.length).toBeGreaterThan(0);
+      
+      const stats = monitor.getStats('search_by_node_types');
+      expect(stats!.average).toBeLessThan(50); // Complex JSON searches under 50ms
+    });
+  });
+
+  describe('Database Optimization', () => {
+    it('should benefit from proper indexing', () => {
+      // Insert data
+      const nodes = generateNodes(5000);
+      const transaction = db.transaction((nodes: ParsedNode[]) => {
+        nodes.forEach(node => nodeRepo.saveNode(node));
+      });
+      transaction(nodes);
+
+      // Test queries that use indexes
+      const indexedQueries = [
+        () => nodeRepo.getNodesByPackage('n8n-nodes-base'),
+        () => nodeRepo.getNodesByCategory('trigger'),
+        () => nodeRepo.getAITools()
+      ];
+
+      indexedQueries.forEach((query, i) => {
+        const stop = monitor.start(`indexed_query_${i}`);
+        const results = query();
+        stop();
+        
+        expect(Array.isArray(results)).toBe(true);
+      });
+
+      // All indexed queries should be fast
+      indexedQueries.forEach((_, i) => {
+        const stats = monitor.getStats(`indexed_query_${i}`);
+        expect(stats!.average).toBeLessThan(20); // Indexed queries under 20ms
+      });
+    });
+
+    it('should handle VACUUM operation efficiently', () => {
+      // Insert and delete data to create fragmentation
+      const nodes = generateNodes(1000);
+      
+      // Insert
+      const insertTx = db.transaction((nodes: ParsedNode[]) => {
+        nodes.forEach(node => nodeRepo.saveNode(node));
+      });
+      insertTx(nodes);
+
+      // Delete half
+      db.prepare('DELETE FROM nodes WHERE ROWID % 2 = 0').run();
+
+      // Measure VACUUM performance
+      const stop = monitor.start('vacuum');
+      db.exec('VACUUM');
+      stop();
+
+      const stats = monitor.getStats('vacuum');
+      expect(stats!.average).toBeLessThan(1000); // VACUUM under 1 second
+
+      // Verify database still works
+      const remaining = nodeRepo.getAllNodes();
+      expect(remaining.length).toBeGreaterThan(0);
+    });
+
+    it('should maintain performance with WAL mode', () => {
+      // Verify WAL mode is enabled
+      const mode = db.prepare('PRAGMA journal_mode').get() as { journal_mode: string };
+      expect(mode.journal_mode).toBe('wal');
+
+      // Perform mixed read/write operations
+      const operations = 1000;
+      
+      const stop = monitor.start('wal_mixed_operations');
+      
+      for (let i = 0; i < operations; i++) {
+        if (i % 10 === 0) {
+          // Write operation
+          const node = generateNodes(1)[0];
+          nodeRepo.saveNode(node);
+        } else {
+          // Read operation
+          nodeRepo.getAllNodes(10);
+        }
+      }
+      
+      stop();
+
+      const stats = monitor.getStats('wal_mixed_operations');
+      expect(stats!.average).toBeLessThan(500); // Mixed operations under 500ms
+    });
+  });
+
+  describe('Memory Usage', () => {
+    it('should handle large result sets without excessive memory', () => {
+      // Insert large dataset
+      const nodes = generateNodes(10000);
+      const transaction = db.transaction((nodes: ParsedNode[]) => {
+        nodes.forEach(node => nodeRepo.saveNode(node));
+      });
+      transaction(nodes);
+
+      // Measure memory before
+      const memBefore = process.memoryUsage().heapUsed;
+
+      // Fetch large result set
+      const stop = monitor.start('large_result_set');
+      const results = nodeRepo.getAllNodes();
+      stop();
+
+      // Measure memory after
+      const memAfter = process.memoryUsage().heapUsed;
+      const memIncrease = (memAfter - memBefore) / 1024 / 1024; // MB
+
+      expect(results).toHaveLength(10000);
+      expect(memIncrease).toBeLessThan(100); // Less than 100MB increase
+
+      const stats = monitor.getStats('large_result_set');
+      expect(stats!.average).toBeLessThan(200); // Fetch 10k records under 200ms
+    });
+  });
+
+  describe('Concurrent Write Performance', () => {
+    it('should handle concurrent writes with transactions', () => {
+      const writeBatches = 10;
+      const nodesPerBatch = 100;
+
+      const stop = monitor.start('concurrent_writes');
+
+      // Simulate concurrent write batches
+      const promises = Array.from({ length: writeBatches }, (_, i) => {
+        return new Promise<void>((resolve) => {
+          const nodes = generateNodes(nodesPerBatch, i * nodesPerBatch);
+          const transaction = db.transaction((nodes: ParsedNode[]) => {
+            nodes.forEach(node => nodeRepo.saveNode(node));
+          });
+          transaction(nodes);
+          resolve();
+        });
+      });
+
+      Promise.all(promises);
+      stop();
+
+      const stats = monitor.getStats('concurrent_writes');
+      expect(stats!.average).toBeLessThan(500); // All writes under 500ms
+
+      // Verify all nodes were written
+      const count = nodeRepo.getNodeCount();
+      expect(count).toBe(writeBatches * nodesPerBatch);
+    });
+  });
+});
+
+// Helper functions
+function generateNodes(count: number, startId: number = 0): ParsedNode[] {
+  const categories = ['trigger', 'automation', 'transform', 'output'];
+  const packages = ['n8n-nodes-base', '@n8n/n8n-nodes-langchain'];
+  
+  return Array.from({ length: count }, (_, i) => ({
+    nodeType: `n8n-nodes-base.node${startId + i}`,
+    packageName: packages[i % packages.length],
+    displayName: `Node ${startId + i}`,
+    description: `Description for node ${startId + i} with ${['webhook', 'http', 'automation', 'data'][i % 4]} functionality`,
+    category: categories[i % categories.length],
+    style: 'programmatic' as const,
+    isAITool: i % 10 === 0,
+    isTrigger: categories[i % categories.length] === 'trigger',
+    isWebhook: i % 5 === 0,
+    isVersioned: true,
+    version: '1',
+    documentation: i % 3 === 0 ? `Documentation for node ${i}` : null,
+    properties: Array.from({ length: 5 }, (_, j) => ({
+      displayName: `Property ${j}`,
+      name: `prop${j}`,
+      type: 'string',
+      default: ''
+    })),
+    operations: [],
+    credentials: i % 4 === 0 ? [{ name: 'httpAuth', required: true }] : []
+  }));
+}
+
+function generateDescription(index: number): string {
+  const descriptions = [
+    'Automate your workflow with powerful webhook integrations',
+    'Process HTTP requests and transform data efficiently',
+    'Connect to external APIs and sync data seamlessly',
+    'Build complex automation workflows with ease',
+    'Transform and filter data with advanced operations'
+  ];
+  return descriptions[index % descriptions.length] + ` - Version ${index}`;
+}
\ No newline at end of file
diff --git a/tests/integration/database/template-repository.test.ts b/tests/integration/database/template-repository.test.ts
new file mode 100644
index 0000000..73fccd8
--- /dev/null
+++ b/tests/integration/database/template-repository.test.ts
@@ -0,0 +1,439 @@
+import { describe, it, expect, beforeEach, afterEach } from '@jest/globals';
+import * as Database from 'better-sqlite3';
+import { TemplateRepository } from '../../../src/templates/template-repository';
+import { DatabaseAdapter } from '../../../src/database/database-adapter';
+import { TestDatabase, TestDataGenerator } from './test-utils';
+import { TemplateWorkflow, TemplateDetail } from '../../../src/templates/template-fetcher';
+
+describe('TemplateRepository Integration Tests', () => {
+  let testDb: TestDatabase;
+  let db: Database;
+  let repository: TemplateRepository;
+  let adapter: DatabaseAdapter;
+
+  beforeEach(async () => {
+    testDb = new TestDatabase({ mode: 'memory', enableFTS5: true });
+    db = await testDb.initialize();
+    adapter = new DatabaseAdapter(db);
+    repository = new TemplateRepository(adapter);
+  });
+
+  afterEach(async () => {
+    await testDb.cleanup();
+  });
+
+  describe('saveTemplate', () => {
+    it('should save single template successfully', () => {
+      const template = createTemplateWorkflow();
+      repository.saveTemplate(template);
+
+      const saved = repository.getTemplate(template.id);
+      expect(saved).toBeTruthy();
+      expect(saved?.workflow_id).toBe(template.id);
+      expect(saved?.name).toBe(template.name);
+    });
+
+    it('should update existing template', () => {
+      const template = createTemplateWorkflow();
+      
+      // Save initial version
+      repository.saveTemplate(template);
+      
+      // Update and save again
+      const updated: TemplateWorkflow = { ...template, name: 'Updated Template' };
+      repository.saveTemplate(updated);
+
+      const saved = repository.getTemplate(template.id);
+      expect(saved?.name).toBe('Updated Template');
+      
+      // Should not create duplicate
+      const all = repository.getAllTemplates();
+      expect(all).toHaveLength(1);
+    });
+
+    it('should handle templates with complex node types', () => {
+      const template = createTemplateWorkflow({
+        id: 1,
+        nodes: [
+          {
+            id: 'node1',
+            name: 'Webhook',
+            type: 'n8n-nodes-base.webhook',
+            typeVersion: 1,
+            position: [100, 100],
+            parameters: {}
+          },
+          {
+            id: 'node2',
+            name: 'HTTP Request',
+            type: 'n8n-nodes-base.httpRequest',
+            typeVersion: 3,
+            position: [300, 100],
+            parameters: {
+              url: 'https://api.example.com',
+              method: 'POST'
+            }
+          }
+        ]
+      });
+
+      repository.saveTemplate(template);
+      
+      const saved = repository.getTemplate(template.id);
+      expect(saved).toBeTruthy();
+      
+      const nodesUsed = JSON.parse(saved!.nodes_used);
+      expect(nodesUsed).toContain('n8n-nodes-base.webhook');
+      expect(nodesUsed).toContain('n8n-nodes-base.httpRequest');
+    });
+
+    it('should sanitize workflow data before saving', () => {
+      const template = createTemplateWorkflow({
+        workflowInfo: {
+          nodeCount: 5,
+          webhookCount: 1,
+          // Add some data that should be sanitized
+          executionId: 'should-be-removed',
+          pinData: { node1: { data: 'sensitive' } }
+        }
+      });
+
+      repository.saveTemplate(template);
+      
+      const saved = repository.getTemplate(template.id);
+      expect(saved).toBeTruthy();
+      
+      const workflowJson = JSON.parse(saved!.workflow_json);
+      expect(workflowJson.pinData).toBeUndefined();
+    });
+  });
+
+  describe('getTemplate', () => {
+    beforeEach(() => {
+      const templates = [
+        createTemplateWorkflow({ id: 1, name: 'Template 1' }),
+        createTemplateWorkflow({ id: 2, name: 'Template 2' })
+      ];
+      templates.forEach(t => repository.saveTemplate(t));
+    });
+
+    it('should retrieve template by id', () => {
+      const template = repository.getTemplate(1);
+      expect(template).toBeTruthy();
+      expect(template?.name).toBe('Template 1');
+    });
+
+    it('should return null for non-existent template', () => {
+      const template = repository.getTemplate(999);
+      expect(template).toBeNull();
+    });
+  });
+
+  describe('searchTemplates with FTS5', () => {
+    beforeEach(() => {
+      const templates = [
+        createTemplateWorkflow({
+          id: 1,
+          name: 'Webhook to Slack',
+          description: 'Send Slack notifications when webhook received'
+        }),
+        createTemplateWorkflow({
+          id: 2,
+          name: 'HTTP Data Processing',
+          description: 'Process data from HTTP requests'
+        }),
+        createTemplateWorkflow({
+          id: 3,
+          name: 'Email Automation',
+          description: 'Automate email sending workflow'
+        })
+      ];
+      templates.forEach(t => repository.saveTemplate(t));
+    });
+
+    it('should search templates by name', () => {
+      const results = repository.searchTemplates('webhook');
+      expect(results).toHaveLength(1);
+      expect(results[0].name).toBe('Webhook to Slack');
+    });
+
+    it('should search templates by description', () => {
+      const results = repository.searchTemplates('automate');
+      expect(results).toHaveLength(1);
+      expect(results[0].name).toBe('Email Automation');
+    });
+
+    it('should handle multiple search terms', () => {
+      const results = repository.searchTemplates('data process');
+      expect(results).toHaveLength(1);
+      expect(results[0].name).toBe('HTTP Data Processing');
+    });
+
+    it('should limit search results', () => {
+      // Add more templates
+      for (let i = 4; i <= 20; i++) {
+        repository.saveTemplate(createTemplateWorkflow({
+          id: i,
+          name: `Test Template ${i}`,
+          description: 'Test description'
+        }));
+      }
+
+      const results = repository.searchTemplates('test', 5);
+      expect(results).toHaveLength(5);
+    });
+
+    it('should handle special characters in search', () => {
+      repository.saveTemplate(createTemplateWorkflow({
+        id: 100,
+        name: 'Special @ # $ Template',
+        description: 'Template with special characters'
+      }));
+
+      const results = repository.searchTemplates('special');
+      expect(results.length).toBeGreaterThan(0);
+    });
+  });
+
+  describe('getTemplatesByNodeTypes', () => {
+    beforeEach(() => {
+      const templates = [
+        createTemplateWorkflow({
+          id: 1,
+          nodes: [
+            { type: 'n8n-nodes-base.webhook' },
+            { type: 'n8n-nodes-base.slack' }
+          ]
+        }),
+        createTemplateWorkflow({
+          id: 2,
+          nodes: [
+            { type: 'n8n-nodes-base.httpRequest' },
+            { type: 'n8n-nodes-base.set' }
+          ]
+        }),
+        createTemplateWorkflow({
+          id: 3,
+          nodes: [
+            { type: 'n8n-nodes-base.webhook' },
+            { type: 'n8n-nodes-base.httpRequest' }
+          ]
+        })
+      ];
+      templates.forEach(t => repository.saveTemplate(t));
+    });
+
+    it('should find templates using specific node types', () => {
+      const results = repository.getTemplatesByNodeTypes(['n8n-nodes-base.webhook']);
+      expect(results).toHaveLength(2);
+      expect(results.map(r => r.workflow_id)).toContain(1);
+      expect(results.map(r => r.workflow_id)).toContain(3);
+    });
+
+    it('should find templates using multiple node types', () => {
+      const results = repository.getTemplatesByNodeTypes([
+        'n8n-nodes-base.webhook',
+        'n8n-nodes-base.slack'
+      ]);
+      expect(results).toHaveLength(1);
+      expect(results[0].workflow_id).toBe(1);
+    });
+
+    it('should return empty array for non-existent node types', () => {
+      const results = repository.getTemplatesByNodeTypes(['non-existent-node']);
+      expect(results).toHaveLength(0);
+    });
+
+    it('should limit results', () => {
+      const results = repository.getTemplatesByNodeTypes(['n8n-nodes-base.webhook'], 1);
+      expect(results).toHaveLength(1);
+    });
+  });
+
+  describe('getAllTemplates', () => {
+    it('should return empty array when no templates', () => {
+      const templates = repository.getAllTemplates();
+      expect(templates).toHaveLength(0);
+    });
+
+    it('should return all templates with limit', () => {
+      for (let i = 1; i <= 20; i++) {
+        repository.saveTemplate(createTemplateWorkflow({ id: i }));
+      }
+
+      const templates = repository.getAllTemplates(10);
+      expect(templates).toHaveLength(10);
+    });
+
+    it('should order templates by updated_at descending', () => {
+      // Save templates with slight delay to ensure different timestamps
+      const template1 = createTemplateWorkflow({ id: 1, name: 'First' });
+      repository.saveTemplate(template1);
+
+      // Small delay
+      const template2 = createTemplateWorkflow({ id: 2, name: 'Second' });
+      repository.saveTemplate(template2);
+
+      const templates = repository.getAllTemplates();
+      expect(templates).toHaveLength(2);
+      // Most recent should be first
+      expect(templates[0].name).toBe('Second');
+    });
+  });
+
+  describe('getTemplateDetail', () => {
+    it('should return template with full workflow data', () => {
+      const template = createTemplateDetail();
+      repository.saveTemplateDetail(template);
+
+      const saved = repository.getTemplateDetail(template.id);
+      expect(saved).toBeTruthy();
+      expect(saved?.workflow).toBeTruthy();
+      expect(saved?.workflow.nodes).toHaveLength(template.workflow.nodes.length);
+    });
+
+    it('should handle missing workflow gracefully', () => {
+      const template = createTemplateWorkflow({ id: 1 });
+      repository.saveTemplate(template);
+
+      const detail = repository.getTemplateDetail(1);
+      expect(detail).toBeNull();
+    });
+  });
+
+  describe('clearOldTemplates', () => {
+    it('should remove templates older than specified days', () => {
+      // Insert old template (30 days ago)
+      db.prepare(`
+        INSERT INTO templates (
+          id, workflow_id, name, description,
+          nodes_used, workflow_json, categories, views,
+          created_at, updated_at
+        ) VALUES (?, ?, ?, ?, '[]', '{}', '[]', 0, datetime('now', '-31 days'), datetime('now', '-31 days'))
+      `).run(1, 1001, 'Old Template', 'Old template');
+
+      // Insert recent template
+      repository.saveTemplate(createTemplateWorkflow({ id: 2, name: 'Recent Template' }));
+
+      // Clear templates older than 30 days
+      const deleted = repository.clearOldTemplates(30);
+      expect(deleted).toBe(1);
+
+      const remaining = repository.getAllTemplates();
+      expect(remaining).toHaveLength(1);
+      expect(remaining[0].name).toBe('Recent Template');
+    });
+  });
+
+  describe('Transaction handling', () => {
+    it('should rollback on error during bulk save', () => {
+      const templates = [
+        createTemplateWorkflow({ id: 1 }),
+        createTemplateWorkflow({ id: 2 }),
+        { id: null } as any // Invalid template
+      ];
+
+      expect(() => {
+        templates.forEach(t => repository.saveTemplate(t));
+      }).toThrow();
+
+      // No templates should be saved due to error
+      const all = repository.getAllTemplates();
+      expect(all).toHaveLength(0);
+    });
+  });
+
+  describe('FTS5 performance', () => {
+    it('should handle large dataset searches efficiently', () => {
+      // Insert 1000 templates
+      const templates = Array.from({ length: 1000 }, (_, i) => 
+        createTemplateWorkflow({
+          id: i + 1,
+          name: `Template ${i}`,
+          description: `Description for ${['webhook', 'http', 'automation', 'data'][i % 4]} workflow ${i}`
+        })
+      );
+
+      const insertMany = db.transaction((templates: TemplateWorkflow[]) => {
+        templates.forEach(t => repository.saveTemplate(t));
+      });
+
+      const start = Date.now();
+      insertMany(templates);
+      const insertDuration = Date.now() - start;
+
+      expect(insertDuration).toBeLessThan(2000); // Should complete in under 2 seconds
+
+      // Test search performance
+      const searchStart = Date.now();
+      const results = repository.searchTemplates('webhook', 50);
+      const searchDuration = Date.now() - searchStart;
+
+      expect(searchDuration).toBeLessThan(50); // Search should be very fast
+      expect(results).toHaveLength(50);
+    });
+  });
+});
+
+// Helper functions
+function createTemplateWorkflow(overrides: any = {}): TemplateWorkflow {
+  const id = overrides.id || Math.floor(Math.random() * 10000);
+  const nodes = overrides.nodes || [
+    {
+      id: 'node1',
+      name: 'Start',
+      type: 'n8n-nodes-base.start',
+      typeVersion: 1,
+      position: [100, 100],
+      parameters: {}
+    }
+  ];
+
+  return {
+    id,
+    name: overrides.name || `Test Workflow ${id}`,
+    workflow: {
+      nodes: nodes.map((n: any) => ({
+        id: n.id || 'node1',
+        name: n.name || 'Node',
+        type: n.type || 'n8n-nodes-base.start',
+        typeVersion: n.typeVersion || 1,
+        position: n.position || [100, 100],
+        parameters: n.parameters || {}
+      })),
+      connections: overrides.connections || {},
+      settings: overrides.settings || {}
+    },
+    user: {
+      username: overrides.username || 'testuser'
+    },
+    views: overrides.views || 100,
+    totalViews: overrides.totalViews || 100,
+    createdAt: overrides.createdAt || new Date().toISOString(),
+    updatedAt: overrides.updatedAt || new Date().toISOString(),
+    description: overrides.description,
+    workflowInfo: overrides.workflowInfo || {
+      nodeCount: nodes.length,
+      webhookCount: nodes.filter((n: any) => n.type?.includes('webhook')).length
+    },
+    ...overrides
+  };
+}
+
+function createTemplateDetail(overrides: any = {}): TemplateDetail {
+  const base = createTemplateWorkflow(overrides);
+  return {
+    ...base,
+    workflow: {
+      id: base.id.toString(),
+      name: base.name,
+      nodes: base.workflow.nodes,
+      connections: base.workflow.connections,
+      settings: base.workflow.settings,
+      pinData: overrides.pinData
+    },
+    categories: overrides.categories || [
+      { id: 1, name: 'automation' }
+    ]
+  };
+}
\ No newline at end of file