[luatex] MySQL driver not found from inside LuaLaTeX

[sergei . naumov]

Hi!
I am new to LuaTeX and LuaLaTeX, please, bear with my ignorance of some
probably basic things. :-) I need to get strings from MySQL database and
the test Lua code that does it works fine when it is called from the
command line:

require("string")
function projects_from_db ()
    DBI = require("DBI")
    dbh = assert(DBI.Connect('MySQL','serge', 'serge', 'serge',
'localhost', 3306))
    sth = assert(dbh:prepare('SELECT name,budget FROM projects'))
    sth:execute()
    for row in sth:rows() do
        print(string.format("%-55s & %7.1f \\\\",row[1],row[2]))
    end
    dbh:close()
end

-- projects_from_db()

However, when I put it into latex file

\usepackage{luacode}
\usepackage{luapackageloader}
\directlua{dofile('dbd.lua')}
\newcommand{\projectsfromdb}{\luadirect{projects_from_db()}}

It says that MySQL driver can not be found:
./DBI.lua:53: Cannot load driver MySQL. Available drivers are: (None)
stack traceback:
       [C]: in function 'error'
       ./DBI.lua:53: in function 'DBI.Connect'
       dbd.lua:6: in function 'projects_from_db'
       [\directlua]:1: in main chunk.
\luadirect ... { \luacode@maybe@printdbg {#1} #1 }

l.64    \projectsfromdb

Why is that? I checked package.cpath from Lua and the necessary path is
there:

Lua 5.3.6  Copyright (C) 1994-2020 Lua.org, PUC-Rio
> package.cpath
/usr/lib64/lua/5.3/?.so;/usr/lib64/lua/5.3/loadall.so;./?.so

I tried to set a few environment variables:

LUAROCKS_CPATH=/usr/lib64/lua/5.3
LUAROCKS_PATH=/usr/share/lua/5.3

but it did not make any difference

-- 
Thanks,
Sergei