data-access-abstraction

Name: data-access-abstraction
Author: DanWahlin

36stars10forks

How to install data-access-abstraction?

danwahlin/github-azure-agentic-journeys/data-access-abstraction

$npx -y skills add DanWahlin/github-azure-agentic-journeys --skill data-access-abstraction

Installs into the current project.

Summary

Data access abstraction patterns for apps that need to swap between local databases (SQLite) and cloud databases (Cosmos DB, PostgreSQL) without changing application code. Covers Node.js/TypeScript, Python/FastAPI, and .NET. Use when building apps that run locally with SQLite and

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SKILL.md

1	# Data Access Abstraction
2
3	Build APIs with swappable data layers using the repository pattern. Develop locally with SQLite, deploy to Azure with Cosmos DB or PostgreSQL — same route code, different backend. Works in any language.
4
5	## When to Use This Skill
6
7	- Building an API that needs to run locally (SQLite) and in Azure (Cosmos DB or PostgreSQL)
8	- Adding a new data provider to an existing app without changing routes or business logic
9	- Migrating from one database to another incrementally
10	- Any project following the AIMarket journey pattern (local dev → cloud deploy)
11
12	## Pattern Overview
13
14	The pattern is the same regardless of language:
15
16	```
17	Routes/Controllers → Repository Interfaces → Factory → Implementations
18	│
19	├── SQLite (local dev)
20	├── Cosmos DB (Azure deploy)
21	├── PostgreSQL (Azure deploy)
22	└── In-memory (testing)
23	```
24
25	Three rules:
26	1. Define repository interfaces (or abstract classes / protocols) per entity
27	2. Routes depend only on the interfaces — never import a database client directly
28	3. A factory reads a config value (`DATA_PROVIDER`) and returns the right implementation
29
30	Adding a new database means writing a new implementation file. Zero changes to routes.
31
32	## Environment Variable
33
34	All languages use the same convention:
35
36	```
37	DATA_PROVIDER=sqlite # Local development (default)
38	DATA_PROVIDER=cosmos # Azure Cosmos DB
39	DATA_PROVIDER=postgres # Azure PostgreSQL
40	```
41
42	---
43
44	## Node.js / TypeScript
45
46	### Repository Interfaces
47
48	```typescript
49	// data/interfaces.ts
50
51	export interface IProductRepository {
52	getAll(params: {
53	page: number; pageSize: number;
54	category?: string; minPrice?: number; maxPrice?: number;
55	}): Promise<{ data: Product[]; totalCount: number }>;
56
57	getById(id: string): Promise<Product \| null>;
58	create(input: CreateProductInput): Promise<Product>;
59	update(id: string, fields: Partial<Product>): Promise<Product \| null>;
60	}
61
62	export interface IOrderRepository {
63	create(input: CreateOrderInput): Promise<Order>;
64	getById(id: string): Promise<Order \| null>;
65	getByUserId(userId: string, page: number, pageSize: number): Promise<{ data: Order[]; totalCount: number }>;
66	}
67
68	export interface IUserRepository {
69	create(input: CreateUserInput): Promise<User>;
70	getById(id: string): Promise<User \| null>;
71	getByEmail(email: string): Promise<User \| null>;
72	}
73
74	export interface DataStore {
75	products: IProductRepository;
76	orders: IOrderRepository;
77	users: IUserRepository;
78	close?(): void;
79	}
80	```
81
82	### Factory
83
84	```typescript
85	// data/store.ts
86
87	export async function createStore(): Promise<DataStore> {
88	const provider = process.env.DATA_PROVIDER \|\| 'sqlite';
89	switch (provider) {
90	case 'sqlite':
91	return (await import('./sqlite.js')).createSqliteStore();
92	case 'cosmos':
93	return (await import('./cosmos.js')).createCosmosStore();
94	case 'postgres':
95	return (await import('./postgres.js')).createPostgresStore();
96	default:
97	throw new Error(`Unknown DATA_PROVIDER: ${provider}`);
98	}
99	}
100	```
101
102	### SQLite Implementation
103
104	Use `better-sqlite3` (synchronous API, fast). Wrap sync calls in `Promise.resolve()` or make routes `await` — sync values resolve immediately.
105
106	```typescript
107	// data/sqlite.ts
108
109	import Database from 'better-sqlite3';
110
111	export function createSqliteStore(dbPath = 'app.db'): DataStore {
112	const db = new Database(dbPath);
113	db.pragma('journal_mode = WAL');
114	db.pragma('foreign_keys = ON');
115	// Create tables, seed if empty...
116
117	return {
118	products: {
119	async getAll({ page, pageSize, category, minPrice, maxPrice }) {
120	let where = 'WHERE status = ?';
121	const params: any[] = ['active'];
122	if (category) { where += ' AND category = ?'; params.push(category); }
123	if (minPrice != null) { where += ' AND price >= ?'; params.push(minPrice); }
124	if (maxPrice != null) { where += ' AND price <= ?'; params.push(maxPrice); }
125
126	const { c: totalCount } = db.prepare(`SELECT COUNT(*) as c FROM products ${where}`).get(...params);
127	const rows = db.prepare(`SELECT * FROM products ${where} LIMIT ? OFFSET ?`)
128	.all(...params, pageSize, (page - 1) * pageSize);
129	return { data: rows.map(parseRow), totalCount };
130	},
131	// ...
132	},
133	close: () => db.close(),
134	};
135	}
136	```
137
138	SQLite-specific: Store arrays as JSON strings (`JSON.stringify(tags)`), parse on read. Use a junction table for order items.
139
140	### Cosmo

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Type

data-access-abstraction

36stars10forks

View on GitHub

How to install data-access-abstraction?

danwahlin/github-azure-agentic-journeys/data-access-abstraction

$npx -y skills add DanWahlin/github-azure-agentic-journeys --skill data-access-abstraction

Installs into the current project.

Summary

Files · 1

View on GitHub

SKILL.md

1	# Data Access Abstraction
2
3	Build APIs with swappable data layers using the repository pattern. Develop locally with SQLite, deploy to Azure with Cosmos DB or PostgreSQL — same route code, different backend. Works in any language.
4
5	## When to Use This Skill
6
7	- Building an API that needs to run locally (SQLite) and in Azure (Cosmos DB or PostgreSQL)
8	- Adding a new data provider to an existing app without changing routes or business logic
9	- Migrating from one database to another incrementally
10	- Any project following the AIMarket journey pattern (local dev → cloud deploy)
11
12	## Pattern Overview
13
14	The pattern is the same regardless of language:
15
16	```
17	Routes/Controllers → Repository Interfaces → Factory → Implementations
18	│
19	├── SQLite (local dev)
20	├── Cosmos DB (Azure deploy)
21	├── PostgreSQL (Azure deploy)
22	└── In-memory (testing)
23	```
24
25	Three rules:
26	1. Define repository interfaces (or abstract classes / protocols) per entity
27	2. Routes depend only on the interfaces — never import a database client directly
28	3. A factory reads a config value (`DATA_PROVIDER`) and returns the right implementation
29
30	Adding a new database means writing a new implementation file. Zero changes to routes.
31
32	## Environment Variable
33
34	All languages use the same convention:
35
36	```
37	DATA_PROVIDER=sqlite # Local development (default)
38	DATA_PROVIDER=cosmos # Azure Cosmos DB
39	DATA_PROVIDER=postgres # Azure PostgreSQL
40	```
41
42	---
43
44	## Node.js / TypeScript
45
46	### Repository Interfaces
47
48	```typescript
49	// data/interfaces.ts
50
51	export interface IProductRepository {
52	getAll(params: {
53	page: number; pageSize: number;
54	category?: string; minPrice?: number; maxPrice?: number;
55	}): Promise<{ data: Product[]; totalCount: number }>;
56
57	getById(id: string): Promise<Product \| null>;
58	create(input: CreateProductInput): Promise<Product>;
59	update(id: string, fields: Partial<Product>): Promise<Product \| null>;
60	}
61
62	export interface IOrderRepository {
63	create(input: CreateOrderInput): Promise<Order>;
64	getById(id: string): Promise<Order \| null>;
65	getByUserId(userId: string, page: number, pageSize: number): Promise<{ data: Order[]; totalCount: number }>;
66	}
67
68	export interface IUserRepository {
69	create(input: CreateUserInput): Promise<User>;
70	getById(id: string): Promise<User \| null>;
71	getByEmail(email: string): Promise<User \| null>;
72	}
73
74	export interface DataStore {
75	products: IProductRepository;
76	orders: IOrderRepository;
77	users: IUserRepository;
78	close?(): void;
79	}
80	```
81
82	### Factory
83
84	```typescript
85	// data/store.ts
86
87	export async function createStore(): Promise<DataStore> {
88	const provider = process.env.DATA_PROVIDER \|\| 'sqlite';
89	switch (provider) {
90	case 'sqlite':
91	return (await import('./sqlite.js')).createSqliteStore();
92	case 'cosmos':
93	return (await import('./cosmos.js')).createCosmosStore();
94	case 'postgres':
95	return (await import('./postgres.js')).createPostgresStore();
96	default:
97	throw new Error(`Unknown DATA_PROVIDER: ${provider}`);
98	}
99	}
100	```
101
102	### SQLite Implementation
103
104	Use `better-sqlite3` (synchronous API, fast). Wrap sync calls in `Promise.resolve()` or make routes `await` — sync values resolve immediately.
105
106	```typescript
107	// data/sqlite.ts
108
109	import Database from 'better-sqlite3';
110
111	export function createSqliteStore(dbPath = 'app.db'): DataStore {
112	const db = new Database(dbPath);
113	db.pragma('journal_mode = WAL');
114	db.pragma('foreign_keys = ON');
115	// Create tables, seed if empty...
116
117	return {
118	products: {
119	async getAll({ page, pageSize, category, minPrice, maxPrice }) {
120	let where = 'WHERE status = ?';
121	const params: any[] = ['active'];
122	if (category) { where += ' AND category = ?'; params.push(category); }
123	if (minPrice != null) { where += ' AND price >= ?'; params.push(minPrice); }
124	if (maxPrice != null) { where += ' AND price <= ?'; params.push(maxPrice); }
125
126	const { c: totalCount } = db.prepare(`SELECT COUNT(*) as c FROM products ${where}`).get(...params);
127	const rows = db.prepare(`SELECT * FROM products ${where} LIMIT ? OFFSET ?`)
128	.all(...params, pageSize, (page - 1) * pageSize);
129	return { data: rows.map(parseRow), totalCount };
130	},
131	// ...
132	},
133	close: () => db.close(),
134	};
135	}
136	```
137
138	SQLite-specific: Store arrays as JSON strings (`JSON.stringify(tags)`), parse on read. Use a junction table for order items.
139
140	### Cosmo

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Type