mame/plugins/data/database.lua

local sql = require("lsqlite3")
local datfile = {}
local db

function check_db(msg)
	if db:errcode() > sqlite3.OK then
		io.stderr:write("Error: " .. msg .. " (" .. db:errcode() .. " - " .. db:errmsg() .. ")\n")
	end
end

do
	local dbpath = lfs.env_replace(mame_manager:ui():options().entries.historypath:value():match("([^;]+)"))
	db = sql.open(dbpath .. "/history.db")
	if not db then
		lfs.mkdir(dbpath)
		db = sql.open(dbpath .. "/history.db")
		check_db("opening database")
	end
end

if db then
	local found = false
	db:exec("select * from sqlite_master where name = 'version'", function() found = true return 0 end)
	check_db("checking for 'version' table")
	if not found then
		db:exec([[
			CREATE TABLE version (
				version VARCHAR NOT NULL,
				datfile VARCHAR UNIQUE NOT NULL)]])
		check_db("creating 'version' table")
	end
end

return function() return db, sql end