# 🛠️ SQL Parser Developer Guide
SQL support for the Oak language framework.
This guide is designed to help you quickly get started with developing and integrating `oak-sql`.
## 🚦 Quick Start
Add the dependency to your `Cargo.toml`:
```toml
[dependencies]
oak-sql = { path = "..." }
```
### Basic Parsing Example
The following is a standard workflow for parsing a complex SQL query with Joins and CTEs:
```rust
use oak_sql::{SqlParser, SourceText, SqlLanguage};
fn main() {
// 1. Prepare source code (PostgreSQL dialect)
let code = r#"
WITH regional_sales AS (
SELECT region, SUM(amount) AS total_sales
FROM orders
GROUP BY region
)
SELECT product_name, total_sales
FROM regional_sales
JOIN products ON products.region = regional_sales.region
WHERE total_sales > 10000
ORDER BY total_sales DESC;
"#;
let source = SourceText::new(code);
// 2. Initialize parser with specific dialect configuration
let config = SqlLanguage::postgresql();
let parser = SqlParser::new(&config);
// 3. Execute parsing
let result = parser.parse(&source);
// 4. Handle results
if result.is_success() {
println!("Parsing successful! AST node count: {}", result.node_count());
} else {
eprintln!("Errors found during parsing.");
}
}
```
## 🔍 Core API Usage
### 1. Syntax Tree Traversal
After a successful parse, you can use the built-in visitor pattern or manually traverse the Green/Red Tree to extract SQL-specific constructs like CTE definitions, Join conditions, `WHERE` clauses, or DDL table structures.
### 2. Incremental Parsing
No need to re-parse an entire multi-megabyte SQL dump when small changes occur:
```rust
// Assuming you have an old parse result 'old_result' and new source text 'new_source'
let new_result = parser.reparse(&new_source, &old_result);
```
### 3. Diagnostics
`oak-sql` provides rich error contexts specifically tailored for database developers, handling dialect-specific syntax quirks and providing clear feedback on malformed queries:
```rust
for diag in result.diagnostics() {
println!("[{}:{}] {}", diag.line, diag.column, diag.message);
}
```
## 🏗️ Architecture Overview
- **Lexer**: Tokenizes SQL source text into a stream of tokens, handling keywords, operators, quoted identifiers, and dialect-specific literals.
- **Parser**: Syntax analyzer based on the Pratt parsing algorithm to handle SQL's complex expression precedence, multi-dialect support, and deeply nested query structures.
- **AST**: A strongly-typed syntax abstraction layer designed for high-performance SQL analysis tools, query formatters, and IDEs.
## 🔗 Advanced Resources
- **Full Examples**: Check the [examples/](examples/) folder in the project root.
- **API Documentation**: Run `cargo doc --open` for detailed type definitions.
- **Test Cases**: See [tests/](tests/) for handling of various SQL dialects and edge cases.