MiniDB

MiniDB is a compact relational database engine written in C. It ships as a single CLI binary with a SQL shell, persistent on-disk storage, catalog metadata, primary and secondary indexes, transactions, and write-ahead logging.

Current version: 0.1.2

Capabilities

• Persistent database directory under mydb/
• SQL shell with parser, binder, planner, and executor layers
• INT and TEXT column types
• CREATE TABLE, INSERT, SELECT, UPDATE, and DELETE
• CREATE INDEX and DROP INDEX
• PRIMARY KEY and NOT NULL constraints
• Comparison predicates with =, !=, >, <, >=, and <=
• Primary-key B+ tree indexes
• Secondary indexes
• Catalog persistence
• Write-ahead log recovery path
• CI-backed checks with formatting, static analysis, unit tests, and sanitizers

Install

Download a binary release for your platform, extract it, and run the installer:

tar -xzf MiniDB-0.1.2-<system>-<machine>.tar.gz
cd MiniDB-0.1.2-<system>-<machine>
./install.sh
MiniDB --version

By default, the installer copies MiniDB to /usr/local/bin. To install without elevated permissions, use a user-local prefix:

PREFIX="$HOME/.local" ./install.sh

Make sure $HOME/.local/bin is on your PATH when using a custom prefix.

Build From Source

Requirements:

• C11 compiler such as gcc or clang
• make

Build and run from a source checkout:

make
./MiniDB

Install from source:

make install
MiniDB --version

Use a custom install prefix when needed:

make install PREFIX="$HOME/.local"

Uninstall from the same prefix:

make uninstall PREFIX="$HOME/.local"

Usage

Start the shell:

MiniDB

or, from an uninstalled source checkout:

make run

Example session:

CREATE TABLE users (id INT PRIMARY KEY, name TEXT NOT NULL, age INT);
INSERT INTO users VALUES (1, "Finn", 20);
INSERT INTO users VALUES (2, "Alex", 21);
SELECT * FROM users;
SELECT name, age FROM users WHERE id = 1;
UPDATE users SET age = 22 WHERE name = "Alex";
DELETE FROM users WHERE id = 1;
.tables
.schema users
.exit

MiniDB currently accepts one SQL statement per input line. SQL statements end with a semicolon. Shell commands start with a dot and do not need a semicolon.

Supported SQL

CREATE TABLE table_name (
    column_name INT [PRIMARY KEY] [NOT NULL],
    column_name TEXT [NOT NULL]
);

CREATE INDEX index_name ON table_name (column_name [, column_name ...]);
DROP INDEX index_name;

INSERT INTO table_name VALUES (1, "text");

SELECT * FROM table_name;
SELECT column_name [, column_name ...] FROM table_name
    [WHERE column_name = 1];

DELETE FROM table_name [WHERE column_name != "text"];

UPDATE table_name SET column_name = value
    [WHERE column_name >= value];

Supported shell commands:

.help
.exit
.tables
.schema <table>

Verification

Run the full local verification suite:

make check

This runs:

• make fmt-check
• make analyze
• make test
• make test-asan

Run only the unit suite:

make test

Releases

Create source and binary release archives:

make release

This runs make check, then writes:

dist/MiniDB-0.1.2.tar.gz
dist/MiniDB-0.1.2-<system>-<machine>.tar.gz

Create only the source archive:

make dist

Create only the binary archive:

make package

Remove generated release artifacts:

make clean-dist

Runtime Files

The default database path is mydb/.

mydb/
  catalog.db
  minidb.wal
  tables/
    table_name.tbl
  indexes/
    table_name_pk.btree
    index_name.sidx

Runtime database files are local state and should not be committed.

Documentation

• USAGE
• DEVELOPMENT
• ARCHITECTURE
• RELEASE

License

MiniDB is licensed under the MIT License.