diff --git a/api/src/category.repository.test.ts b/api/src/category.repository.test.ts
index d03256b..c8933bb 100644
--- a/api/src/category.repository.test.ts
+++ b/api/src/category.repository.test.ts
@@ -1,40 +1,44 @@
 import { describe, it } from 'node:test';
 import assert from 'node:assert/strict';
-import { CategoryRepository } from './category.repository';
+import { CategoryRepository } from './category.repository.ts';
+import { Pool } from 'pg';
 
-describe('CategoryRepository - ltree SQL Generator', () => {
-    const repository = new CategoryRepository();
+// Lightweight mock generator for the pg Pool
+function createMockDb(mockRows: any[]) {
+    const tracker = { lastQuery: { text: '', values: [] as any[] } };
+    const mockPool = {
+        query: async (text: string, values: any[]) => {
+            tracker.lastQuery = { text, values };
+            return { rows: mockRows };
+        }
+    } as unknown as Pool;
 
-    describe('generateDescendantsQuery()', () => {
-        it('should generate valid SQL using the ltree descenant operator (<@)', () => {
-            const parentPath = 'Top.Science';
-            const result = repository.generateDescendantsQuery(parentPath);
+    return { mockPool, tracker };
+}
 
-            // veriy the generated SQL syntax as correct ltree
-            assert.match(result.sql, /<@/);
-            assert.match(result.sql, /::ltree/);
-            assert.deepEqual(result.values, ['Top.Science']);
-        });
+describe('CategoryRepository - ltree Queries', () => {
+    it('should format findAllDescendants query using the ltree descendant operator (<@)', async () => {
+        const mockData = [{ id: 2, name: 'Science', path: 'Top.Science' }];
+        const { mockPool, tracker } = createMockDb(mockData);
+        const repository = new CategoryRepository(mockPool);
+
+        const result = await repository.findAllDescendants('Top.Science');
+
+        // Verify data output matches mock rows
+        assert.deepEqual(result, mockData);
+
+        // Verify generated SQL uses the right operator and bindings
+        assert.match(tracker.lastQuery.text, /<@/);
+        assert.deepEqual(tracker.lastQuery.values, ['Top.Science']);
     });
 
-    describe('generateWildcardQuery()', () => {
-        it('should generate valid SQL utilizing an lquery matching operator (~)', () => {
-            const result = repository.generateWildcardQuery('Top.*.Astronomy');
+    it('should format findDirectChildren query with level matching requirements', async () => {
+        const { mockPool, tracker } = createMockDb([]);
+        const repository = new CategoryRepository(mockPool);
 
-            assert.match(result.sql, /~/);
-            assert.match(result.sql, /::lquery/);
-            assert.equal(result.values[0], 'Top.*.Astronomy');
-        });
+        await repository.findDirectChildren('Top');
+
+        assert.match(tracker.lastQuery.text, /nlevel\(path\)/);
+        assert.deepEqual(tracker.lastQuery.values, ['Top.*', 'Top']);
     });
-
-    describe('isValidLtreePath() validation utility', () => {
-        it('should pass for correctly formatted dot-separated ltree structures', () => {
-            assert.equal(repository.isValidLtreePath('Top.Hobbies.Amateurs_Astronomy'), true);
-        });
-
-        it('should fail if special characters or spaces are introduced into the path', () => {
-            assert.equal(repository.isValidLtreePath('Top.Hobbies.Bad Path!'), false);
-            assert.equal(repository.isValidLtreePath('Top..InvalidDoubleDot'), false);
-        });
-    });
-});
\ No newline at end of file
+});
diff --git a/api/src/category.repository.ts b/api/src/category.repository.ts
index 22477c5..3afac7b 100644
--- a/api/src/category.repository.ts
+++ b/api/src/category.repository.ts
@@ -1,30 +1,58 @@
-// structural interface to the test table
-export interface CatetoryNode {
+import { Pool } from 'pg';
+
+export interface CategoryNode {
     id: number;
     name: string;
-    path: string; // ltree field
+    path: string;
 }
 
 export class CategoryRepository {
-    // simulate generating a SQL query targeting child paths
-    generateDescendantsQuery(parentPath: string): { sql: string; values: string[] } {
-        return {
-            sql: 'SELECT id, name, path FROM categories WHERE path <@ $1::ltree',
-            values: [parentPath]
-        };
+    // Inject the database connection pool
+    constructor(private db: Pool) { }
+
+    /**
+     * Finds all descendants of a given path (including the path itself).
+     * Uses the ltree operator <@ (is-descendant-of).
+     */
+    async findAllDescendants(parentPath: string): Promise<CategoryNode[]> {
+        const query = `
+      SELECT id, name, path 
+      FROM categories 
+      WHERE path <@ $1::ltree
+      ORDER BY path ASC;
+    `;
+        const result = await this.db.query(query, [parentPath]);
+        return result.rows;
     }
 
-    generateWildcardQuery(pattern: string): { sql: string, values: string[] } {
-        // Simulate genrating a SQL query using ltree wildcards
-        return {
-            sql: 'SELECT id, name, path FROM categories WHERE path ~ $1::lquery',
-            values: [pattern]
-        };
+    /**
+     * Finds only the direct children of a given path.
+     * Uses lquery pattern matching (parent.*) and matches the exact next depth level.
+     */
+    async findDirectChildren(parentPath: string): Promise<CategoryNode[]> {
+        const query = `
+      SELECT id, name, path 
+      FROM categories 
+      WHERE path ~ $1::lquery 
+        AND nlevel(path) = nlevel($2::ltree) + 1;
+    `;
+        const values = [`${parentPath}.*`, parentPath];
+        const result = await this.db.query(query, values);
+        return result.rows;
     }
 
-    // helper utility to validate a string as an ltree value
-    isValidLtreePath(path: string): boolean {
-        const ltreeRegex = /^[A-Za-z0-9_]+(\.[A-Za-z0-9_]+)*$/;
-        return ltreeRegex.test(path);
+    /**
+     * Finds all ancestors of a path (useful for breadcrumbs).
+     * Uses the ltree operator @> (is-ancestor-of).
+     */
+    async findAncestors(childPath: string): Promise<CategoryNode[]> {
+        const query = `
+      SELECT id, name, path 
+      FROM categories 
+      WHERE path @> $1::ltree 
+      ORDER BY nlevel(path) ASC;
+    `;
+        const result = await this.db.query(query, [childPath]);
+        return result.rows;
     }
-}
\ No newline at end of file
+}