luadb

a Lua extension for database access

Introduction

This extension provides database access. It currently supports:

• PostgreSQL

Usage

local db = require('luadb')
db.connect_postgres('postgresql://...') -- connect via connection string

ok = db.ping() -- returns ok if ping successful; or throws an error
rows = db.query('select * from ...') -- runs query and returns rows as table of tables; or throws an error
lastId, rowsAffected = db.exec('insert into ...') -- executes query, and returns state vars as integers; or throws an error

Build

Assumes a Lua version is installed as static lib (liblua.a) (which is standard at least for Lua 5.4) in /usr/local/lib/.

To build run:

make build

DBMS

PostgreSQL

• Supports mapping for most generic types
  • SMALLINT, INT, BIGINT are returned as integer (which correlates to C double double)
  • REAL, DOUBLE are returned as number (which correlates to C double)
  • CHAR, VARCHAR, TEXT are returned as string
  • DATE, TIME, TIMETZ, TIMESTAMP, TIMESTAMPTZ are returned a ISO8601 representing string
  • BOOL is returned as boolean
  • BYTEA is returned as "byte table"
• Supports mapping of JSON and JSONB fields to Lua tables
• Supports mapping of NUMERIC and DECIMAL to numbers
• All not mapable data is returned as "byte table"

Contribute

It would be nice to grow this library to include also support for other relational DBMS's.

Contributions are welcome.