Crate hematite 

Hematite is a small embeddable SQL database written in Rust.

It is designed to stay lightweight enough to repurpose and extend while still offering a surprisingly broad SQL surface: DDL, transactions, views, triggers, joins, aggregates, window functions, recursive CTEs, savepoints, rich scalar expressions, and a custom type system.

Quick Start

use hematite::Hematite;

fn main() -> hematite::Result<()> {
    let mut db = Hematite::new_in_memory()?;
    db.execute("CREATE TABLE users (id INT PRIMARY KEY, name TEXT);")?;
    db.execute("INSERT INTO users (id, name) VALUES (1, 'Ada');")?;

    let names = db.query("SELECT name FROM users ORDER BY id;")?;
    assert_eq!(names.columns, vec!["name"]);
    assert_eq!(names.rows.len(), 1);
    Ok(())
}

Main Entry Points

• Hematite is the high-level library facade.
• Connection is the lower-level SQL connection boundary.
• PreparedStatement supports repeated execution with parameters.
• Transaction wraps explicit transactions.
• ResultSet, Row, and StatementResult are the primary result types.

Project Layout

The core architecture is layered:

sql -> parser -> query -> catalog -> btree -> storage

• sql: user-facing API, script stepping, transactions, CLI-facing behavior
• parser: lexer, AST, and syntax validation
• query: planning, execution, coercion, metadata shaping
• catalog: schema, row typing, metadata persistence, logical encoding
• btree: generic key/value tree over byte payloads
• storage: pager, WAL/rollback journal, page and row primitives

More Documentation

• Repository quick start: README.md
• Internal architecture guide: docs/architecture.md
• Module and codebase guide: docs/codebase-guide.md
• SQL dialect and support matrix: docs/sql-dialect.md

Re-exports

pub use catalog::Catalog;

pub use catalog::Column;

pub use catalog::DataType;

pub use catalog::Schema;

pub use catalog::StoredRow;

pub use catalog::Table;

pub use catalog::TableCursor;

pub use catalog::Value;

pub use error::HematiteError;

pub use error::Result;

pub use parser::parser::Parser;

pub use parser::Lexer;

pub use sql::script_is_complete;

pub use sql::Connection;

pub use sql::Database;

pub use sql::ExecutedStatement;

pub use sql::FromRow;

pub use sql::FromValue;

pub use sql::Hematite;

pub use sql::PreparedStatement;

pub use sql::ResultSet;

pub use sql::Row;

pub use sql::StatementResult;

pub use sql::Transaction;

pub use parser::ast::*;

Modules

btree

Generic B-tree module over opaque byte keys and values.

catalog

Relational catalog and access-method layer.

error

Error handling for Hematite database

parser

SQL query parser for converting tokens to AST

query

Query processing module

sql

SQL interface module

storage

Low-level storage primitives.