Luasql error: "LuaSQL: error connecting to database"

Question

I am working on mysql. I am trying to acess the mysql database using the Luasql.I have installed Luasql using yum. Then i tried the following code:

mysql = require "luasql.mysql"

env = assert(mysql.mysql())

con = assert(env:connect ( "db_name", "username", "password", "localhost"))

for no, name in rows (con, "select * from t1") do

print (string.format ("%s", name))

end

While executing the above code i am getting the following error :

lua: check.lua:3: LuaSQL: error connecting to database. MySQL: Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)
stack traceback:
    [C]: in function 'assert'
    check.lua:3: in main chunk
    [C]: ?

How to overcome this error.Can anyone help me for the proper execution of the code? Thanks !!!

Have you tried using your real `db_name`, `username` and `password` ? — Egor Skriptunoff, Jun 26 '14 at 07:47
Are you able to connect to the database using standard tools? — Egor Skriptunoff, Jun 26 '14 at 09:24
Probably, you are using non-standard port? Try `env:connect(..., "localhost", your_port)` — Egor Skriptunoff, Jun 26 '14 at 11:54
@Egor i am getting this error " LuaSQL: error connecting to database. MySQL: Can't connect to MySQL server on '3306' (22) " — robin, Jun 26 '14 at 12:08
Your error means you passed `3306` as hostname, not as port. Your arguments for `connect` function seem to be shifted. Are you sure you are using `env:connect(...)`, not `env.connect(...)` ? — Egor Skriptunoff, Jun 26 '14 at 12:20
@EgorSkriptunoff connection is established but now the error is in for loop which states " lua: check.lua:4: attempt to call global 'row' (a nil value) " — robin, Jun 26 '14 at 12:48

score 1 · Answer 1 · edited Jun 27 '14 at 04:17

1

the variables in env:connect should be variables such as below

local db_conn = env:connect("test_db", "root", "abc123", "192.168.1.3", 3306)
local cur = db_conn:execute("select * from t1")
local row = cur:fetch({}, 'a')
for k, v in pairs(row) do
    print(k, v)
end

edited Jun 27 '14 at 04:17

robin

19
1
10

answered Jun 27 '14 at 02:30

freedoo

691
1
5
12

i am getting this error lua: check.lua:4: attempt to index local 'db_conn' (a nil value) stack traceback: check.lua:4: in main chunk [C]: ? – robin Jun 27 '14 at 04:14
1

uh, i think u know the basic example. your database name may be not 'test_db', your database host may be not '192.168.1.3', your name and password may be not 'root' and 'abc123', so u can't get an connect instance. – freedoo Jun 29 '14 at 07:28

score 0 · Accepted Answer · answered Jun 27 '14 at 05:02

This code executes well..thank u both @ EgorSkriptunoff &jaylzhang for ur responses

mysql = require "luasql.mysql"
env = assert(mysql.mysql())
con = assert(env:connect ( "db_name", "username", "password", "hostname", "3306"))
local cur = con:execute("select * from t1")
local row = cur:fetch({}, 'a')
for k, v in pairs(row) do
    print(k, v)
end

score 0 · Answer 3 · edited Jan 24 '19 at 09:20

Try this. It will work with ZeroBraneIDE. Change the interpreter to lua instead of Lua 5.2 or 5.3.

You need to create System DSN on ODBC Data Sources from administrative tool, here it is "testDSN", as shown here:

require "luasql.odbc"
  env = assert(luasql.odbc())
  print(env)
  con = assert(env:connect("testDSN", "sa", "p@ssw0rd"))
  print(con)
  cur = assert (con:execute"use testdb")
  cur = assert (con:execute"SELECT MSISD FROM MSID")
  row = cur:fetch({}, "a")

  while row do
    print(string.format("%s",row.MSISD))
    row = cur:fetch (row, "a")
  end

  cur:close()
  con:close()
  env:close()

Luasql error: "LuaSQL: error connecting to database"

3 Answers3

Linked