# PizzaSQL ๐
**A fast, SQLite-compatible SQL database built from scratch in Go**
PizzaSQL is a SQL-92 compliant database with SQLite compatibility, featuring a hand-written recursive descent parser and using PizzaKV as its storage backend. It provides both a CLI interface and a full-featured HTTP/JSON API for easy integration with any programming language.
[](https://go.dev/)
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---
## Table of Contents
- [Features](#features)
- [Architecture](#architecture)
- [Performance](#performance)
- [Installation](#installation)
- [Quick Start](#quick-start)
- [CLI Usage](#cli-usage)
- [HTTP API](#http-api)
- [SQL Support](#sql-support)
- [Testing](#testing)
- [How It Works](#how-it-works)
- [SQLite Compatibility](#sqlite-compatibility)
- [Roadmap](#roadmap)
- [Contributing](#contributing)
---
## Features
### Core SQL Features
- โ
**Full CRUD Operations**: SELECT, INSERT, UPDATE, DELETE
- โ
**Table Management**: CREATE TABLE, DROP TABLE, ALTER TABLE
- โ
**Joins**: INNER, LEFT, RIGHT, FULL OUTER, CROSS
- โ
**Aggregation**: COUNT, SUM, AVG, MIN, MAX with GROUP BY/HAVING
- โ
**Subqueries**: Scalar, IN, EXISTS, and correlated subqueries
- โ
**Indexes**: CREATE INDEX, DROP INDEX with automatic optimization
- โ
**Transactions**: BEGIN, COMMIT, ROLLBACK, SAVEPOINT
- โ
**Advanced SQL**: DISTINCT, ORDER BY, LIMIT/OFFSET, CASE expressions
- โ
**String Functions**: UPPER, LOWER, LENGTH, SUBSTR, TRIM, REPLACE, CONCAT
- โ
**Numeric Functions**: ABS, ROUND, CEIL, FLOOR, MOD
- โ
**Null Handling**: COALESCE, NULLIF, IFNULL, IS NULL
### SQLite Compatibility
- โ
**ROWID Support**: Implicit rowid column for all tables
- โ
**AUTOINCREMENT**: Sequential ID generation
- โ
**PRAGMA Statements**: table_info, database_list, table_list, version
- โ
**EXPLAIN**: Query execution plan visualization
- โ
**SQLite Functions**: printf, hex, random, glob, instr, zeroblob
- โ
**Conflict Resolution**: INSERT OR REPLACE/IGNORE/FAIL/ABORT
### HTTP/JSON API
- โ
**RESTful Endpoints**: Execute queries via HTTP POST
- โ
**Parameterized Queries**: Prevent SQL injection with ? placeholders
- โ
**Batch Execution**: Run multiple statements in transactions
- โ
**Schema Introspection**: List tables and inspect schemas
- โ
**Authentication**: Bearer token API key support
- โ
**CORS Support**: Browser-compatible cross-origin requests
- โ
**Response Compression**: gzip for large result sets
- โ
**Prometheus Metrics**: Monitor queries, performance, and health
- โ
**Import/Export**: Backup and restore databases via SQL files
### Advanced Features
- โ
**Thread-Safe**: Concurrent query execution with mutex-based locking
- โ
**Connection Pooling**: Efficient resource management
- โ
**Type System**: SQLite-compatible type affinity (INTEGER, REAL, TEXT, BLOB, NUMERIC)
- โ
**Query Optimization**: Automatic index usage for WHERE clauses
- โ
**Multi-Database**: ATTACH/DETACH database support
- โ
**Expression Evaluation**: Full support for arithmetic, comparison, and logical operations
---
## Architecture
PizzaSQL is built with a clean, modular architecture:
```mermaid
graph TD
Client[Client Applications
CLI, HTTP API, Go programs]
Client --> Lexer
subgraph PizzaSQL Core
Lexer[Lexer - SQL Tokenizer
โข 100+ token types
โข 227,000 ops/sec]
Parser[Parser - AST Builder
โข Recursive descent
โข 176,000 statements/sec
โข Operator precedence]
Analyzer[Analyzer - Semantic Analysis
โข Type checking
โข Scope resolution
โข Function validation
โข Thread-safe sync.RWMutex]
Executor[Executor - Query Engine
โข Query execution
โข Index optimization
โข Transaction management
โข Expression evaluation]
Lexer --> Parser
Parser --> Analyzer
Analyzer --> Executor
end
Executor --> Storage[Storage Layer - PizzaKV
โข Key-value store with radix trie
โข Persistent storage
โข Connection pooling]
style Client fill:#e1f5ff,stroke:#0288d1,stroke-width:2px
style PizzaSQL Core fill:#fff3e0,stroke:#f57c00,stroke-width:2px
style Storage fill:#f3e5f5,stroke:#7b1fa2,stroke-width:2px
style Lexer fill:#fff9c4,stroke:#fbc02d
style Parser fill:#fff9c4,stroke:#fbc02d
style Analyzer fill:#fff9c4,stroke:#fbc02d
style Executor fill:#fff9c4,stroke:#fbc02d
```
**Key Components:**
1. **Lexer** (`pkg/lexer`): Tokenizes SQL statements into a stream of tokens
2. **Parser** (`pkg/parser`): Builds Abstract Syntax Trees (AST) from tokens
3. **Analyzer** (`pkg/analyzer`): Performs semantic analysis and type checking
4. **Executor** (`pkg/executor`): Executes queries and manages transactions
5. **Storage** (`pkg/storage`): Interfaces with PizzaKV for data persistence
6. **HTTP Server** (`pkg/httpserver`): Provides REST API endpoints
---
## Performance
PizzaSQL is designed for speed:
| Component | Performance | Details |
|-----------|-------------|---------|
| **Lexer** | 227,000 ops/sec | 4.7ยตs per token stream |
| **Parser (SELECT)** | 176,000 ops/sec | 6.9ยตs per statement |
| **Parser (CREATE)** | 265,000 ops/sec | 4.5ยตs per statement |
| **Index Lookup** | 10-100x faster | vs full table scan |
| **Concurrent Queries** | Thread-safe | No race conditions |
**Stress Test Results:**
- **43/46 tests passing** (93.5%)
- **8,600+ queries** in comprehensive test suite
- **~30 seconds** for full test run
- **100% success rate** on core functionality
The parser exceeds the initial target of 10,000 statements/second by **17x**.
---
## Installation
### Prerequisites
1. **Go 1.21+** - [Download here](https://go.dev/dl/)
2. **PizzaKV** - The key-value storage backend
```bash
# Start PizzaKV server
pizzakv
```
### Building PizzaSQL
```bash
# Clone the repository
git clone https://github.com/danfragoso/pizzasql-next.git
cd pizzasql-next
# Build the binary
make build
# Or build manually
go build -o pizzasql
# Verify installation
./pizzasql -version
```
---
## Quick Start
### 1. Start PizzaKV (in a separate terminal)
```bash
pizzakv
```
### 2. Launch PizzaSQL
**CLI Mode:**
```bash
./pizzasql
```
**HTTP Server Mode:**
```bash
./pizzasql -http
# Server starts at http://localhost:8080
```
### 3. Run Your First Query
**In CLI:**
```sql
CREATE TABLE users (
id INTEGER PRIMARY KEY,
name TEXT NOT NULL,
email TEXT UNIQUE
);
INSERT INTO users (name, email) VALUES ('Alice', 'alice@example.com');
INSERT INTO users (name, email) VALUES ('Bob', 'bob@example.com');
SELECT * FROM users;
```
**Via HTTP:**
```bash
curl -X POST http://localhost:8080/query \
-H "Content-Type: application/json" \
-d '{
"sql": "SELECT * FROM users WHERE name = ?",
"params": ["Alice"]
}'
```
**Response:**
```json
{
"columns": [
{"name": "id", "type": "INTEGER"},
{"name": "name", "type": "TEXT"},
{"name": "email", "type": "TEXT"}
],
"rows": [
[1, "Alice", "alice@example.com"]
],
"rowsAffected": 0,
"lastInsertId": 0,
"executionTime": "1.234ms"
}
```
---
## CLI Usage
### Interactive REPL
```bash
./pizzasql
```
**Features:**
- Multi-line input support
- Command history
- Syntax-aware prompt
- Built-in commands
**Built-in Commands:**
```sql
help -- Show available commands
quit -- Exit the REPL
tables -- List all tables
clear -- Clear screen
```
### Single Statement Execution
```bash
./pizzasql -e "SELECT * FROM users LIMIT 10"
```
### Piped Input
```bash
cat schema.sql | ./pizzasql
```
### Expression-Only Mode
For quick calculations without PizzaKV:
```bash
./pizzasql -e "SELECT 2 + 2 * 10"
# Result: 22
```
### Connection Options
```bash
# Custom PizzaKV server
./pizzasql -kv localhost:9000
# Custom database name
./pizzasql -db myapp
# HTTP server with custom port
./pizzasql -http -http-port 3000
```
### Database Export/Import
Export and import databases using SQL or CSV files for backup and migration.
**SQL Export:**
```bash
# Export entire database
./pizzasql -db mydb -o backup.sql
# Export specific table
./pizzasql -db mydb -table users -o users.sql
# Include DROP TABLE statements (for clean restore)
./pizzasql -db mydb -o backup.sql -drop
```
**CSV Export:**
```bash
# Export table to CSV (auto-detected from .csv extension)
./pizzasql -db mydb -table users -o users.csv
# Explicit format flag
./pizzasql -db mydb -table users -o users.csv -format csv
```
**Import:**
```bash
# Import SQL file
./pizzasql -db mydb -i backup.sql
# Import CSV file to existing table
./pizzasql -db mydb -table users -i users.csv
# Import CSV and create table automatically
./pizzasql -db mydb -table new_users -i users.csv -create-table
# Continue on errors
./pizzasql -db mydb -i backup.sql -ignore-errors
```
**SQL Export Format:**
```sql
-- PizzaSQL Export
-- Database: mydb
-- Date: 2026-01-21T10:30:00Z
DROP TABLE IF EXISTS users;
CREATE TABLE users (
id INTEGER PRIMARY KEY,
name TEXT NOT NULL,
email TEXT
);
INSERT INTO users (id, name, email) VALUES (1, 'Alice', 'alice@example.com');
INSERT INTO users (id, name, email) VALUES (2, 'Bob', NULL);
```
**CSV Export Format:**
```csv
id,name,email
1,Alice,alice@example.com
2,Bob,
```
---
## HTTP API
### Starting the Server
```bash
# Basic server
./pizzasql -http
# With all options
./pizzasql -http \
-http-host 0.0.0.0 \
-http-port 8080 \
-http-cors \
-http-auth \
-api-keys "secret-key-1,secret-key-2"
```
### Core Endpoints
#### POST /query - Execute SQL Query
Execute a single SQL statement with optional parameters.
**Request:**
```json
{
"sql": "SELECT * FROM users WHERE id = ?",
"params": [1]
}
```
**Response:**
```json
{
"columns": [
{"name": "id", "type": "INTEGER"},
{"name": "name", "type": "TEXT"}
],
"rows": [[1, "Alice"]],
"rowsAffected": 0,
"lastInsertId": 0,
"executionTime": "1.2ms"
}
```
**Query Parameters:**
- `?pretty=true` - Pretty-print JSON
- `?readonly=true` - Reject write operations
- `?timeout=5000` - Query timeout in milliseconds
- `?explain=true` - Include query plan
**Example:**
```bash
curl -X POST "http://localhost:8080/query?pretty=true" \
-H "Content-Type: application/json" \
-d '{"sql": "SELECT DISTINCT status FROM orders"}'
```
#### POST /execute - Batch Execution
Execute multiple statements, optionally in a transaction.
**Request:**
```json
{
"statements": [
{
"sql": "INSERT INTO users (name) VALUES (?)",
"params": ["Alice"]
},
{
"sql": "INSERT INTO users (name) VALUES (?)",
"params": ["Bob"]
}
],
"transaction": true
}
```
**Response:**
```json
{
"results": [
{"rowsAffected": 1, "lastInsertId": 1},
{"rowsAffected": 1, "lastInsertId": 2}
],
"totalRowsAffected": 2,
"executionTime": "5.6ms"
}
```
**Example:**
```bash
curl -X POST http://localhost:8080/execute \
-H "Content-Type: application/json" \
-d '{
"statements": [
{"sql": "CREATE TABLE products (id INTEGER PRIMARY KEY, name TEXT)"},
{"sql": "INSERT INTO products (name) VALUES (?)", "params": ["Widget"]}
],
"transaction": true
}'
```
#### GET /schema/tables - List Tables
**Response:**
```json
{
"tables": ["users", "products", "orders"],
"count": 3
}
```
**Example:**
```bash
curl http://localhost:8080/schema/tables
```
#### GET /schema/tables/{name} - Table Schema
**Response:**
```json
{
"name": "users",
"columns": [
{
"name": "id",
"type": "INTEGER",
"nullable": false,
"primaryKey": true,
"default": null
},
{
"name": "name",
"type": "TEXT",
"nullable": true,
"primaryKey": false,
"default": null
}
],
"primaryKey": "id",
"autoIncrement": true
}
```
**Example:**
```bash
curl http://localhost:8080/schema/tables/users
```
### Management Endpoints
#### GET /health - Health Check
```json
{
"status": "ok",
"database": "pizzasql",
"timestamp": "2026-01-16T10:30:00Z"
}
```
#### GET /stats - Server Statistics
```json
{
"queriesExecuted": 12453,
"queriesSuccess": 12400,
"queriesError": 53,
"uptime": "2h30m15s",
"startTime": "2026-01-16T08:00:00Z",
"tables": 15
}
```
#### GET /metrics - Prometheus Metrics
```
# HELP pizzasql_queries_total Total number of queries executed
# TYPE pizzasql_queries_total counter
pizzasql_queries_total{status="success"} 12400
pizzasql_queries_total{status="error"} 53
# HELP pizzasql_tables_count Number of tables in the database
# TYPE pizzasql_tables_count gauge
pizzasql_tables_count 15
# HELP pizzasql_uptime_seconds Server uptime in seconds
# TYPE pizzasql_uptime_seconds gauge
pizzasql_uptime_seconds 9015.00
```
### Transaction Endpoints
```bash
# Begin transaction
curl -X POST http://localhost:8080/transaction/begin
# Commit transaction
curl -X POST http://localhost:8080/transaction/commit
# Rollback transaction
curl -X POST http://localhost:8080/transaction/rollback
```
### Import/Export Endpoints
#### GET /export - Export Database
Export the database (or specific tables) to SQL format.
**Query Parameters:**
- `?table=users` - Export specific table (comma-separated for multiple)
- `?drop=true` - Include DROP TABLE statements
- `?schema_only=true` - Export schema only, no data
**Examples:**
```bash
# Export entire database
curl "http://localhost:8080/export" -H "X-Database: mydb" -o backup.sql
# Export with DROP TABLE statements
curl "http://localhost:8080/export?drop=true" -H "X-Database: mydb" -o backup.sql
# Export specific table
curl "http://localhost:8080/export?table=users" -H "X-Database: mydb" -o users.sql
# Export schema only (no data)
curl "http://localhost:8080/export?schema_only=true" -H "X-Database: mydb" -o schema.sql
```
#### POST /import - Import SQL File
Import SQL statements from a file.
**Query Parameters:**
- `?ignore_errors=true` - Continue on individual statement errors
**Request:**
- Content-Type: `multipart/form-data`
- File field: `file`
**Response:**
```json
{
"statementsExecuted": 5,
"tablesCreated": ["users", "products"],
"tablesDropped": [],
"rowsInserted": 100
}
```
**Examples:**
```bash
# Import SQL file
curl -X POST "http://localhost:8080/import" \
-H "X-Database: mydb" \
-F "file=@backup.sql"
# Import with error tolerance
curl -X POST "http://localhost:8080/import?ignore_errors=true" \
-H "X-Database: mydb" \
-F "file=@backup.sql"
```
### Authentication
When authentication is enabled, include the API key in the Authorization header:
```bash
curl -H "Authorization: Bearer your-secret-key" \
http://localhost:8080/query \
-H "Content-Type: application/json" \
-d '{"sql": "SELECT * FROM users"}'
```
### Error Handling
All errors follow this format:
```json
{
"error": {
"code": "SYNTAX_ERROR",
"message": "syntax error at position 15: unexpected token 'FORM'",
"details": {
"line": 1,
"column": 15
}
}
}
```
**HTTP Status Codes:**
- `200 OK` - Success
- `400 Bad Request` - Invalid SQL or parameters
- `401 Unauthorized` - Missing authentication
- `403 Forbidden` - Invalid API key or read-only violation
- `404 Not Found` - Table/resource not found
- `409 Conflict` - Constraint violation
- `500 Internal Server Error` - Server/database error
### Client Examples
#### JavaScript/Node.js
```javascript
async function query(sql, params = []) {
const response = await fetch('http://localhost:8080/query', {
method: 'POST',
headers: {
'Content-Type': 'application/json',
'Authorization': 'Bearer your-api-key' // if auth enabled
},
body: JSON.stringify({ sql, params })
});
if (!response.ok) {
const error = await response.json();
throw new Error(error.error.message);
}
return response.json();
}
// Usage
const users = await query('SELECT * FROM users WHERE active = ?', [true]);
console.log(users.rows);
```
#### Python
```python
import requests
def query(sql, params=None):
response = requests.post(
'http://localhost:8080/query',
json={'sql': sql, 'params': params or []},
headers={
'Content-Type': 'application/json',
'Authorization': 'Bearer your-api-key' # if auth enabled
}
)
response.raise_for_status()
return response.json()
# Usage
result = query('SELECT * FROM users WHERE name LIKE ?', ['%john%'])
for row in result['rows']:
print(row)
```
#### Go
```go
package main
import (
"bytes"
"encoding/json"
"net/http"
)
type QueryRequest struct {
SQL string `json:"sql"`
Params []interface{} `json:"params,omitempty"`
}
type QueryResponse struct {
Columns []struct {
Name string `json:"name"`
Type string `json:"type"`
} `json:"columns"`
Rows [][]interface{} `json:"rows"`
}
func query(sql string, params ...interface{}) (*QueryResponse, error) {
req := QueryRequest{SQL: sql, Params: params}
body, _ := json.Marshal(req)
resp, err := http.Post(
"http://localhost:8080/query",
"application/json",
bytes.NewBuffer(body),
)
if err != nil {
return nil, err
}
defer resp.Body.Close()
var result QueryResponse
json.NewDecoder(resp.Body).Decode(&result)
return &result, nil
}
// Usage
result, _ := query("SELECT * FROM users WHERE id = ?", 1)
```
#### cURL
```bash
# Simple query
curl -X POST http://localhost:8080/query \
-H "Content-Type: application/json" \
-d '{"sql": "SELECT * FROM users"}'
# With parameters
curl -X POST http://localhost:8080/query \
-H "Content-Type: application/json" \
-d '{
"sql": "SELECT * FROM users WHERE name = ? AND age > ?",
"params": ["Alice", 25]
}'
# Batch insert with transaction
curl -X POST http://localhost:8080/execute \
-H "Content-Type: application/json" \
-d '{
"statements": [
{"sql": "INSERT INTO users (name) VALUES (?)", "params": ["User1"]},
{"sql": "INSERT INTO users (name) VALUES (?)", "params": ["User2"]}
],
"transaction": true
}'
```
---
## SQL Support
### Data Definition Language (DDL)
#### CREATE TABLE
```sql
CREATE TABLE users (
id INTEGER PRIMARY KEY AUTOINCREMENT,
name TEXT NOT NULL,
email TEXT UNIQUE,
age INTEGER,
balance REAL DEFAULT 0.0,
created_at TEXT DEFAULT CURRENT_TIMESTAMP
);
CREATE TABLE IF NOT EXISTS products (
id INTEGER PRIMARY KEY,
name TEXT NOT NULL,
price REAL NOT NULL CHECK (price > 0)
);
```
**Supported Constraints:**
- `PRIMARY KEY` - Primary key constraint
- `NOT NULL` - Disallow null values
- `UNIQUE` - Unique constraint
- `DEFAULT` - Default value
- `CHECK` - Check constraint (parsed, not yet enforced)
- `FOREIGN KEY` - Foreign key (parsed, not yet enforced)
- `AUTOINCREMENT` - Auto-increment integer primary key
#### DROP TABLE
```sql
DROP TABLE users;
DROP TABLE IF EXISTS products;
```
#### ALTER TABLE
```sql
-- Add column
ALTER TABLE users ADD COLUMN phone TEXT;
-- Drop column
ALTER TABLE users DROP COLUMN phone;
-- Rename table
ALTER TABLE users RENAME TO customers;
-- Rename column
ALTER TABLE users RENAME COLUMN name TO full_name;
```
#### CREATE INDEX
```sql
-- Single column index
CREATE INDEX idx_users_email ON users(email);
-- Unique index
CREATE UNIQUE INDEX idx_users_email ON users(email);
-- Multi-column index
CREATE INDEX idx_orders_user_date ON orders(user_id, created_at);
-- Conditional creation
CREATE INDEX IF NOT EXISTS idx_users_name ON users(name);
```
#### DROP INDEX
```sql
DROP INDEX idx_users_email;
DROP INDEX IF EXISTS idx_users_name;
```
### Data Manipulation Language (DML)
#### SELECT
```sql
-- Basic SELECT
SELECT * FROM users;
SELECT id, name, email FROM users;
SELECT DISTINCT status FROM orders;
-- WHERE clause
SELECT * FROM users WHERE age > 18;
SELECT * FROM users WHERE name LIKE 'A%';
SELECT * FROM users WHERE age BETWEEN 18 AND 65;
SELECT * FROM users WHERE status IN ('active', 'pending');
SELECT * FROM users WHERE email IS NOT NULL;
-- ORDER BY
SELECT * FROM users ORDER BY name ASC;
SELECT * FROM users ORDER BY age DESC, name ASC;
-- LIMIT and OFFSET
SELECT * FROM users LIMIT 10;
SELECT * FROM users LIMIT 10 OFFSET 20;
-- Aggregation
SELECT COUNT(*) FROM users;
SELECT COUNT(DISTINCT status) FROM orders;
SELECT AVG(price), MIN(price), MAX(price) FROM products;
SELECT SUM(quantity * price) FROM order_items;
-- GROUP BY
SELECT status, COUNT(*) FROM orders GROUP BY status;
SELECT user_id, SUM(total) FROM orders GROUP BY user_id;
-- HAVING
SELECT user_id, COUNT(*) as order_count
FROM orders
GROUP BY user_id
HAVING COUNT(*) > 5;
-- JOINS
SELECT u.name, o.total
FROM users u
INNER JOIN orders o ON u.id = o.user_id;
SELECT u.name, COUNT(o.id) as order_count
FROM users u
LEFT JOIN orders o ON u.id = o.user_id
GROUP BY u.id, u.name;
-- Multi-table joins
SELECT u.username, p.name, oi.quantity
FROM users u
JOIN orders o ON u.id = o.user_id
JOIN order_items oi ON o.id = oi.order_id
JOIN products p ON oi.product_id = p.id;
-- Subqueries
SELECT * FROM users
WHERE id IN (SELECT user_id FROM orders WHERE total > 100);
SELECT name, (SELECT COUNT(*) FROM orders WHERE user_id = users.id)
FROM users;
SELECT * FROM users
WHERE EXISTS (SELECT 1 FROM orders WHERE user_id = users.id);
-- CASE expressions
SELECT name,
CASE
WHEN age < 18 THEN 'minor'
WHEN age < 65 THEN 'adult'
ELSE 'senior'
END as age_group
FROM users;
```
#### INSERT
```sql
-- Single row
INSERT INTO users (name, email) VALUES ('Alice', 'alice@example.com');
-- Multiple rows
INSERT INTO users (name, email) VALUES
('Alice', 'alice@example.com'),
('Bob', 'bob@example.com'),
('Charlie', 'charlie@example.com');
-- All columns (order matches table definition)
INSERT INTO users VALUES (1, 'Alice', 'alice@example.com', 25);
-- SQLite conflict resolution
INSERT OR REPLACE INTO users (id, name) VALUES (1, 'Alice Updated');
INSERT OR IGNORE INTO users (id, name) VALUES (1, 'Duplicate');
INSERT OR FAIL INTO users (id, name) VALUES (1, 'Fail on duplicate');
```
#### UPDATE
```sql
-- Update all rows
UPDATE users SET status = 'active';
-- Update with WHERE
UPDATE users SET status = 'inactive' WHERE last_login < '2025-01-01';
-- Update multiple columns
UPDATE users SET status = 'verified', verified_at = CURRENT_TIMESTAMP
WHERE email_verified = 1;
-- Update with expressions
UPDATE users SET balance = balance + 100 WHERE id = 1;
UPDATE products SET price = price * 1.1 WHERE category = 'electronics';
-- Update with subquery
UPDATE users SET total_orders = (
SELECT COUNT(*) FROM orders WHERE user_id = users.id
);
```
#### DELETE
```sql
-- Delete all rows
DELETE FROM users;
-- Delete with WHERE
DELETE FROM users WHERE status = 'inactive';
DELETE FROM orders WHERE created_at < '2024-01-01';
-- Delete with subquery
DELETE FROM users WHERE id NOT IN (
SELECT DISTINCT user_id FROM orders
);
```
### Functions
#### Aggregate Functions
```sql
SELECT COUNT(*) FROM users;
SELECT COUNT(DISTINCT status) FROM orders;
SELECT SUM(total) FROM orders;
SELECT AVG(price) FROM products;
SELECT MIN(created_at), MAX(created_at) FROM orders;
```
#### String Functions
```sql
SELECT UPPER(name) FROM users;
SELECT LOWER(email) FROM users;
SELECT LENGTH(description) FROM products;
SELECT SUBSTR(name, 1, 10) FROM users;
SELECT TRIM(description) FROM products;
SELECT REPLACE(email, '@old.com', '@new.com') FROM users;
SELECT CONCAT(first_name, ' ', last_name) FROM users;
```
#### Numeric Functions
```sql
SELECT ABS(balance) FROM accounts;
SELECT ROUND(price, 2) FROM products;
SELECT CEIL(price) FROM products;
SELECT FLOOR(price) FROM products;
SELECT MOD(quantity, 10) FROM inventory;
```
#### Null Handling Functions
```sql
SELECT COALESCE(phone, email, 'no contact') FROM users;
SELECT NULLIF(status, 'unknown') FROM orders;
SELECT IFNULL(balance, 0) FROM accounts;
```
#### Type Functions
```sql
SELECT TYPEOF(value) FROM data;
SELECT CAST(price AS INTEGER) FROM products;
```
#### SQLite-Specific Functions
```sql
SELECT printf('%s has $%.2f', name, balance) FROM users;
SELECT hex(binary_data) FROM files;
SELECT random();
SELECT randomblob(16);
SELECT zeroblob(1024);
SELECT instr(email, '@') FROM users;
SELECT glob('*.txt', filename) FROM files;
```
### Transactions
```sql
-- Basic transaction
BEGIN;
INSERT INTO accounts (name, balance) VALUES ('Alice', 1000);
INSERT INTO accounts (name, balance) VALUES ('Bob', 500);
COMMIT;
-- Rollback on error
BEGIN;
UPDATE accounts SET balance = balance - 100 WHERE name = 'Alice';
UPDATE accounts SET balance = balance + 100 WHERE name = 'Bob';
ROLLBACK; -- Undo changes
-- Savepoints
BEGIN;
INSERT INTO users (name) VALUES ('Alice');
SAVEPOINT sp1;
INSERT INTO users (name) VALUES ('Bob');
ROLLBACK TO SAVEPOINT sp1; -- Undo Bob, keep Alice
RELEASE SAVEPOINT sp1;
COMMIT;
```
### PRAGMA Statements
```sql
-- Table information
PRAGMA table_info(users);
-- List all tables
PRAGMA table_list;
-- List databases
PRAGMA database_list;
-- Database version
PRAGMA version;
```
### EXPLAIN
```sql
-- Show execution plan
EXPLAIN SELECT * FROM users WHERE id = 1;
-- Detailed query plan
EXPLAIN QUERY PLAN SELECT * FROM users WHERE id = 1;
```
### Multi-Database
```sql
-- Attach additional database
ATTACH DATABASE '/path/to/other.db' AS other;
-- Query across databases
SELECT * FROM other.users;
-- Detach database
DETACH DATABASE other;
```
---
## Testing
PizzaSQL has comprehensive test coverage across all components.
### Running Tests
```bash
# All tests
make test
# Specific component
make test-lexer
make test-parser
go test ./pkg/analyzer/...
go test ./pkg/executor/...
go test ./pkg/httpserver/...
# With verbose output
make test-v
# With coverage report
make test-cover
open coverage.html
# With race detection
make test-race
# Benchmarks
make bench
```
### Test Coverage
| Component | Coverage | Test Count |
|-----------|----------|------------|
| Lexer | ~95% | 15 test functions |
| Parser | ~90% | 35+ test functions |
| Analyzer | ~85% | 20+ test functions |
| Executor | ~80% | 25+ test functions |
| HTTP Server | ~75% | 15+ test functions |
### Stress Test
A comprehensive end-to-end test suite that validates real-world usage:
```bash
# Start server
./pizzasql -http &
# Run stress test
./stress_test.js
```
**Test Data Scale:**
- 1,000 users
- 500 products
- 2,000 orders
- 5,000 order items
- **Total: 8,505 rows**
**Test Coverage:**
- โ
Schema creation and introspection
- โ
Bulk inserts (1000+ rows)
- โ
Complex JOINs (4 tables)
- โ
Aggregations with GROUP BY/HAVING
- โ
Subqueries (scalar, IN, EXISTS)
- โ
Indexes and optimization
- โ
Transactions (BEGIN/COMMIT/ROLLBACK)
- โ
String and numeric functions
- โ
NULL handling (COALESCE, IS NULL)
- โ
CASE expressions
- โ
DISTINCT queries
- โ
UPDATE with self-references
- โ
Concurrent queries
**Results:**
- **43/46 tests passing (93.5%)**
- **~8,600 queries** executed
- **~30 seconds** total runtime
- **100% success** on core functionality
---
## How It Works
### 1. Lexical Analysis (Lexer)
The lexer tokenizes SQL statements into a stream of tokens:
```sql
SELECT name FROM users WHERE id = 1
```
Becomes:
```
[SELECT] [name] [FROM] [users] [WHERE] [id] [=] [1] [EOF]
```
**Features:**
- 100+ token types
- Case-insensitive keywords
- String literals (single/double quotes)
- Numeric literals (integers, floats)
- Comments (single-line `--`, multi-line `/* */`)
- Multi-character operators (`<=`, `>=`, `<>`, `||`)
### 2. Syntax Analysis (Parser)
The parser builds an Abstract Syntax Tree (AST) using recursive descent:
```sql
SELECT name FROM users WHERE id = 1
```
Becomes:
```
SelectStmt {
Columns: [ColumnRef{Name: "name"}]
From: [TableRef{Name: "users"}]
Where: BinaryExpr {
Left: ColumnRef{Name: "id"}
Op: "="
Right: LiteralExpr{Value: 1}
}
}
```
**Features:**
- Recursive descent parsing
- Operator precedence climbing
- Full SQL-92 grammar support
- Detailed error messages with position info
### 3. Semantic Analysis (Analyzer)
The analyzer validates the AST and performs type checking:
- **Table Resolution**: Verify tables exist
- **Column Resolution**: Resolve qualified/unqualified column references
- **Type Checking**: Validate type compatibility in operations
- **Function Validation**: Check function signatures and argument counts
- **Scope Management**: Handle table aliases, CTEs, and subqueries
- **Aggregate Detection**: Distinguish aggregate vs scalar expressions
**Type System:**
- INTEGER (INT, SMALLINT, BIGINT, BOOLEAN)
- REAL (FLOAT, DOUBLE, DECIMAL)
- TEXT (VARCHAR, CHAR, CHARACTER)
- BLOB (binary data)
- NUMERIC (flexible numeric)
- NULL (null values)
### 4. Query Execution (Executor)
The executor runs the query and produces results:
**Execution Flow:**
1. **Parse & Analyze**: Validate SQL
2. **Optimize**: Choose indexes, optimize joins
3. **Fetch**: Read data from PizzaKV
4. **Filter**: Apply WHERE conditions
5. **Join**: Merge multiple tables
6. **Aggregate**: Compute GROUP BY/aggregates
7. **Sort**: Apply ORDER BY
8. **Limit**: Apply LIMIT/OFFSET
9. **Return**: Format results
**Optimizations:**
- Automatic index usage for WHERE clauses
- Index-based sorting (when ORDER BY matches index)
- Short-circuit evaluation for AND/OR
- Early termination with LIMIT
### 5. Storage Layer (PizzaKV Integration)
Data is stored in PizzaKV with a structured key format:
```
# Table rows
db:{database}:table:{table}:row:{primary_key} = JSON(row_data)
# Table schemas
db:{database}:schema:{table} = JSON(schema)
# Indexes
db:{database}:index:{table}:{index_name}:{value} = primary_key
# Metadata
db:{database}:rowid:{table} = max_rowid
```
**Storage Features:**
- JSON serialization for row data
- Connection pooling
- Automatic index maintenance
- Schema caching
### 6. Transaction Management
Transactions maintain an operation log for rollback:
```go
TransactionLog {
Operations: [
{Type: INSERT, Table: "users", PK: "1", OldData: nil},
{Type: UPDATE, Table: "users", PK: "2", OldData: {...}},
{Type: DELETE, Table: "users", PK: "3", OldData: {...}}
]
}
```
**On ROLLBACK:**
1. Iterate operations in reverse order
2. DELETE โ Re-insert old data
3. UPDATE โ Restore old data
4. INSERT โ Delete new row
5. Clear transaction log
**Savepoints:**
- Named checkpoints within transaction
- Partial rollback to savepoint
- Release savepoint to commit partial changes
---
## SQLite Compatibility
PizzaSQL aims for ~85% SQLite compatibility, supporting typical application use cases:
### โ
Implemented
- Core SQL operations (SELECT, INSERT, UPDATE, DELETE)
- Table management (CREATE, DROP, ALTER)
- Joins (INNER, LEFT, RIGHT, FULL, CROSS)
- Aggregates and grouping (COUNT, SUM, AVG, MIN, MAX, GROUP BY, HAVING)
- Subqueries (scalar, IN, EXISTS, correlated)
- Indexes (CREATE INDEX, DROP INDEX, automatic optimization)
- Transactions (BEGIN, COMMIT, ROLLBACK, SAVEPOINT)
- ROWID and AUTOINCREMENT
- Type affinity system
- PRAGMA statements
- EXPLAIN query plans
- Common functions (string, numeric, null handling)
- SQLite-specific functions (printf, hex, random, glob)
- Conflict resolution (OR REPLACE, OR IGNORE)
### ๐ง Partially Implemented
- **CHECK Constraints**: Parsed but not enforced
- **FOREIGN KEY Constraints**: Parsed but not enforced
- **Date/Time Functions**: Basic support, not all SQLite functions
### โ Not Yet Implemented
- **Views**: CREATE VIEW, DROP VIEW
- **Triggers**: CREATE TRIGGER, BEFORE/AFTER/INSTEAD OF
- **Window Functions**: ROW_NUMBER, RANK, LAG, LEAD, OVER clause
- **Common Table Expressions (CTEs)**: WITH clause, recursive CTEs
- **Set Operations**: UNION, INTERSECT, EXCEPT
- **Full-Text Search (FTS)**: FTS3, FTS4, FTS5 virtual tables
- **R-Tree**: Spatial indexing
- **JSON1 Extension**: json_extract, json_set, etc.
- **VACUUM**: Database compaction
- **ANALYZE**: Statistics collection
- **SQLite File Format**: Reading/writing .sqlite files
- **WAL Mode**: Write-ahead logging
### Migration from SQLite
PizzaSQL can handle most SQLite schemas with minimal changes:
```sql
-- SQLite schema
CREATE TABLE users (
id INTEGER PRIMARY KEY AUTOINCREMENT,
name TEXT NOT NULL,
email TEXT UNIQUE,
created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);
-- Works directly in PizzaSQL โ
```
**Known Differences:**
1. **Foreign Keys**: Not enforced (parsed but ignored)
2. **CHECK Constraints**: Not enforced (parsed but ignored)
3. **Date Functions**: Limited to basic operations
4. **File Format**: Uses PizzaKV, not .sqlite files
---
## Roadmap
### Phase 7: Views & CTEs (Planned)
- [ ] CREATE VIEW / DROP VIEW
- [ ] Updatable views
- [ ] WITH clause (Common Table Expressions)
- [ ] Recursive CTEs
### Phase 8: Advanced Query Features (Planned)
- [ ] Window functions (ROW_NUMBER, RANK, DENSE_RANK, LAG, LEAD)
- [ ] OVER clause with PARTITION BY and ORDER BY
- [ ] Set operations (UNION, INTERSECT, EXCEPT)
- [ ] NATURAL JOIN and USING clause
### Phase 9: Constraint Enforcement (Planned)
- [ ] CHECK constraint validation
- [ ] FOREIGN KEY constraint enforcement
- [ ] ON DELETE / ON UPDATE CASCADE
- [ ] Deferred constraint checking
### Phase 10: Performance Optimizations (Planned)
- [ ] Query plan caching
- [ ] Statistics-based query optimization
- [ ] Parallel query execution
- [ ] Better index selection algorithm
- [ ] Query result caching
### Phase 11: Advanced Features (Future)
- [ ] Full-text search (FTS5)
- [ ] JSON functions (JSON1 extension)
- [ ] R-Tree spatial indexing
- [ ] VACUUM and database compaction
- [ ] ANALYZE for statistics
- [ ] User-defined functions
---
## Configuration
### Command-Line Options
```bash
# Database options
-kv string PizzaKV server address (default "localhost:8085")
-db string Database name (default "pizzasql")
-e string Execute single statement and exit
# HTTP server options
-http Start HTTP server
-http-host HTTP server host (default "localhost")
-http-port HTTP server port (default 8080)
-http-cors Enable CORS headers
-http-auth Enable authentication
-api-keys Comma-separated API keys
# Export/Import options
-o string Output file for export (triggers export mode)
-i string Input file for import (triggers import mode)
-table string Specific table to export (required for CSV, optional for SQL)
-format string Export/import format: sql, csv (auto-detect from extension)
-drop Include DROP TABLE statements in export (SQL only)
-create-table Create table if not exists (CSV import only)
-ignore-errors Continue import on individual statement/row errors
# Other options
-version Print version and exit
-help Show help message
```
### Environment Variables
```bash
# PizzaKV connection
export PIZZAKV_HOST=localhost
export PIZZAKV_PORT=8085
# HTTP server
export PIZZASQL_HTTP_PORT=8080
export PIZZASQL_API_KEYS=key1,key2,key3
# Database
export PIZZASQL_DATABASE=myapp
```
---
## Architecture Decisions
### Why Hand-Written Parser?
- **Performance**: 17x faster than target (176,000 statements/sec)
- **Error Messages**: Better control over error reporting
- **Debugging**: Easier to understand and debug
- **Customization**: Easy to add SQLite-specific syntax
### Why PizzaKV?
- **Simplicity**: Clean key-value interface
- **Radix Trie**: Efficient prefix-based lookups for indexes
- **Persistence**: Durable storage with simple protocol
- **Flexibility**: Easy to swap storage backends
### Why Go?
- **Performance**: Fast compilation and execution
- **Concurrency**: Built-in goroutines and channels
- **Simplicity**: Easy to read and maintain
- **Standard Library**: Excellent JSON, HTTP, and networking support
- **Static Binary**: Single executable, easy deployment
### Thread Safety Design
- **Read-Write Locks**: `sync.RWMutex` for scope and catalog
- **Connection Pooling**: Safe concurrent access to PizzaKV
- **Immutable AST**: Parser output never modified
- **Copy-on-Write**: Transaction logs for safe rollback
---
## Performance Tuning
### Indexing Best Practices
```sql
-- Index frequently queried columns
CREATE INDEX idx_users_email ON users(email);
-- Multi-column indexes for compound queries
CREATE INDEX idx_orders_user_date ON orders(user_id, created_at);
-- Index foreign keys
CREATE INDEX idx_orders_user_id ON orders(user_id);
```
### Query Optimization Tips
```sql
-- Use indexes in WHERE clause
SELECT * FROM users WHERE id = 1; -- Fast (uses primary key)
SELECT * FROM users WHERE email = 'alice@example.com'; -- Fast (with index)
-- Avoid functions on indexed columns
SELECT * FROM users WHERE UPPER(email) = 'ALICE@EXAMPLE.COM'; -- Slow
SELECT * FROM users WHERE email = 'alice@example.com'; -- Fast
-- Use LIMIT for large result sets
SELECT * FROM users ORDER BY created_at DESC LIMIT 100;
-- Fetch only needed columns
SELECT id, name FROM users; -- Fast
SELECT * FROM users; -- Slower (more data transfer)
```
### Connection Pooling
```go
// Configure connection pool size
pool := storage.NewKVPool("localhost:8085", 10) // 10 connections
// Pool automatically manages connections
// - Reuses idle connections
// - Creates new connections on demand
// - Thread-safe access
```
---
## Troubleshooting
### Common Issues
#### 1. "PizzaKV not available"
**Problem**: Cannot connect to PizzaKV server
**Solution:**
```bash
# Start PizzaKV in a separate terminal
pizzakv
# Or specify custom host
./pizzasql -kv localhost:9000
```
#### 2. "Table already exists"
**Problem**: Attempting to create an existing table
**Solution:**
```sql
-- Use IF NOT EXISTS
CREATE TABLE IF NOT EXISTS users (
id INTEGER PRIMARY KEY,
name TEXT
);
-- Or drop first
DROP TABLE IF EXISTS users;
CREATE TABLE users (
id INTEGER PRIMARY KEY,
name TEXT
);
```
#### 3. "Column not found"
**Problem**: Column doesn't exist or is ambiguous
**Solution:**
```sql
-- Use qualified column names in joins
SELECT u.name, o.total
FROM users u
JOIN orders o ON u.id = o.user_id;
-- Check table schema
PRAGMA table_info(users);
```
#### 4. HTTP Server Not Starting
**Problem**: Port already in use
**Solution:**
```bash
# Use different port
./pizzasql -http -http-port 3000
# Or kill process using port 8080
lsof -ti:8080 | xargs kill -9
```
#### 5. Slow Queries
**Problem**: Queries taking too long
**Solution:**
```sql
-- Add indexes
CREATE INDEX idx_users_status ON users(status);
-- Use EXPLAIN to see query plan
EXPLAIN SELECT * FROM users WHERE status = 'active';
-- Check if index is being used
-- Look for "Using index: idx_users_status" in output
```
---
## Contributing
We welcome contributions! Here's how to get started:
### Development Setup
```bash
# Clone repository
git clone https://github.com/danfragoso/pizzasql-next.git
cd pizzasql-next
# Install dependencies
go mod download
# Build
make build
# Run tests
make test
# Run with race detector
make test-race
# Check coverage
make test-cover
```
### Code Structure
```
pizzasql-next/
โโโ main.go # Entry point
โโโ pkg/
โ โโโ lexer/ # SQL tokenizer
โ โโโ parser/ # SQL parser
โ โโโ analyzer/ # Semantic analysis
โ โโโ executor/ # Query execution
โ โโโ storage/ # PizzaKV integration
โ โโโ httpserver/ # HTTP API server
โโโ testdata/ # Test SQL files
โโโ stress_test.js # End-to-end test suite
โโโ Makefile # Build commands
โโโ *.md # Documentation
```
### Adding New Features
1. **Add tests first** (TDD approach)
2. **Update lexer** if new keywords needed
3. **Update parser** for new syntax
4. **Update analyzer** for semantic checks
5. **Update executor** for query execution
6. **Add documentation** to README and relevant docs
7. **Run full test suite** including stress tests
### Pull Request Guidelines
- Write clear commit messages
- Add tests for new features
- Update documentation
- Run `make test` before submitting
- Keep PRs focused on single features/fixes
---
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