# sqlite

This rule guides Cursor on SQLite schemas, queries, transactions, and SQL injection defenses. Use it when building local database code.

- rule · `type=rule` · Cursor · ★ 3580
- Author: sanjeed5
- License: CC0-1.0 · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/sanjeed5/awesome-cursor-rules-mdc/tree/HEAD/rules-mdc/sqlite.mdc
- Updated: 2026-05-19
- HTML: https://affpapa.org/en/nevibecode/rules/sqlite

## What it does

The rule guides Cursor through SQLite schema design: it recommends `INTEGER PRIMARY KEY AUTOINCREMENT`, `NOT NULL`, `UNIQUE`, and `FOREIGN KEY` constraints, plus `lower_case_snake_case` names. It also covers WAL mode, indexes for filtering and sorting, and selecting only the columns a query needs.

Write operations should use explicit transactions with `COMMIT` and `ROLLBACK`. User-controlled values should go through prepared statements with bound parameters. The rule also calls for `PRAGMA foreign_keys = ON` and restrictive database file permissions.

SQLite allows one writer at a time, so concurrent writes from multiple processes may call for a client-server relational database.

## Install

### Cursor (native platform)

**Manually: put the files in place**
- File: `.cursor/rules/sqlite.mdc` — Frontmatter: description, globs, alwaysApply

### Claude Code

**Manually: put the files in place**
- File: `.claude/rules/sqlite.md` — The paths frontmatter field limits the files: move globs from the source into paths

### Codex

**AGENTS.md**
- Codex reads AGENTS.md: paste the rule text there

### GitHub Copilot

**Manually: put the files in place**
- File: `.github/instructions/sqlite.instructions.md` — The applyTo field sets which files it applies to: move globs from the source into applyTo

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/rules/sqlite.md`

### Cline

**Manually: put the files in place**
- File: `.clinerules/sqlite.md`

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/sanjeed5/awesome-cursor-rules-mdc/tree/HEAD/rules-mdc/sqlite.mdc

## When to use it
- design an SQLite schema with integrity constraints
- choose indexes for filters and sort order
- wrap related writes in one transaction
- prevent SQL injection in database queries
- enable foreign-key enforcement

## Example prompts
- Review my SQLite schema and suggest constraints for the users and products tables.
- Rewrite these queries so filtering and sorting happen in SQL.
- Check the write flow and add a transaction, rollback handling, and bound parameters.

## Source text · sqlite.mdc · CC0-1.0

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````text
---
description: Definitive guidelines for writing robust, performant, and secure SQLite code. Focuses on schema design, query optimization, and transaction management.
globs: **/*
---
# sqlite Best Practices

SQLite is the go-to embedded SQL engine for local, reliable storage. Adhere to these rules to ensure your SQLite code is maintainable, performant, and secure.

## 1. Data Modeling & Schema Design

Design your schema for integrity and performance from day one.

*   **Primary Keys**: Always use `INTEGER PRIMARY KEY AUTOINCREMENT` for ID columns. This optimizes `rowid` lookups and simplifies ID generation.
    *   ❌ BAD:
        ```sql
        CREATE TABLE users (
            id TEXT PRIMARY KEY, -- Manual UUIDs or similar
            name TEXT NOT NULL
        );
        ```
    *   ✅ GOOD:
        ```sql
        CREATE TABLE users (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            name TEXT NOT NULL
        );
        ```

*   **Data Types & Constraints**: Declare appropriate data types and enforce integrity with `NOT NULL`, `UNIQUE`, and `FOREIGN KEY` constraints.
    *   ❌ BAD:
        ```sql
        CREATE TABLE products (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            name TEXT, -- Allows NULL, no uniqueness
            price REAL
        );
        ```
    *   ✅ GOOD:
        ```sql
        CREATE TABLE products (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            name TEXT NOT NULL UNIQUE,
            price REAL NOT NULL,
            stock INTEGER DEFAULT 0,
            category_id INTEGER,
            FOREIGN KEY (category_id) REFERENCES categories(id) ON DELETE SET NULL
        );
        ```

*   **Naming Conventions**: Use `lower_case_snake_case` for all table, column, and index names. Avoid SQLite keywords as identifiers.
    *   ❌ BAD: `CREATE TABLE My_Users ( UserId INTEGER PRIMARY KEY );`
    *   ✅ GOOD: `CREATE TABLE my_users ( user_id INTEGER PRIMARY KEY );`

## 2. Performance Considerations

Optimize for speed by minimizing I/O and leveraging the SQLite engine.

*   **Enable WAL Mode**: Always enable Write-Ahead Logging for better concurrency and write performance.
    *   ❌ BAD: Default journal mode (`DELETE`).
    *   ✅ GOOD (at database open or once):
        ```sql
        PRAGMA journal_mode = WAL;
        ```

*   **Relax Synchronous Mode**: When using WAL, set `synchronous` to `NORMAL` for faster commits, accepting minimal risk of data loss on power failure (not app crash).
    *   ❌ BAD: Default `synchronous = FULL`.
    *   ✅ GOOD (at database open or once):
        ```sql
        PRAGMA synchronous = NORMAL;
        ```

*   **Indexes**: Create indexes on columns frequently used in `WHERE`, `ORDER BY`, `GROUP BY`, or `JOIN` clauses. Avoid over-indexing.
    *   ❌ BAD:
        ```sql
        SELECT * FROM users WHERE email = 'test@example.com'; -- No index on email
        ```
    *   ✅ GOOD:
        ```sql
        CREATE INDEX idx_users_email ON users(email);
        SELECT id, name FROM users WHERE email = 'test@example.com';
        ```
    *   **Multi-column Indexes**: For queries filtering/sorting on multiple columns, create a multi-column index matching the query order.
        ```sql
        CREATE INDEX idx_products_category_price ON products(category_id, price);
        SELECT * FROM products WHERE category_id = 1 ORDER BY price DESC;
        ```

*   **Query Optimization**: Select only the columns you need. Push filtering, sorting, and aggregation into SQL.
    *   ❌ BAD:
        ```sql
        SELECT * FROM products; -- Fetch all columns
        -- Then filter/sort in application code
        ```
    *   ✅ GOOD:
        ```sql
        SELECT id, name, price FROM products WHERE stock > 0 ORDER BY price ASC LIMIT 10;
        ```

## 3. Transactions & Concurrency

Ensure data consistency and improve write performance with explicit transactions.

*   **Wrap Writes in Transactions**: Group multiple `INSERT`, `UPDATE`, `DELETE` operations within a single transaction. This significantly reduces disk I/O.
````
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First 4079 of 7705 bytes. © sanjeed5 · CC0-1.0 · https://github.com/sanjeed5/awesome-cursor-rules-mdc/tree/HEAD/rules-mdc/sqlite.mdc

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