Question

I’m very new to erlang and I need to code something which inserts rows in a MySQL Database.
How can I prevent SQL Injections with Erlang? Is there also something like prepared statements in other Languages or how should I do it?

Thanks for your replies.

Answer 1

This answer depends on the driver you are using.

Erlang ODBC has a function param_query that binds a set of parameters to the query and it might also escape all the SQL special characters.

erlang-mysql-driver has prepared statements:

%% Register a prepared statement
mysql:prepare(update_developer_country,
              <<"UPDATE developer SET country=? where name like ?">>),

%% Execute the prepared statement
mysql:execute(p1, update_developer_country, [<<"Sweden">>,<<"%Wiger">>]),

(code from Yariv’s blog)

As a last resort you can always escape the characters

 NUL (0x00) --> \0 
 BS  (0x08) --> \b
 TAB (0x09) --> \t
 LF  (0x0a) --> \n
 CR  (0x0d) --> \r
 SUB (0x1a) --> \z
 "   (0x22) --> \"
 %   (0x25) --> \%
 '   (0x27) --> \'
 \   (0x5c) --> \\
 _   (0x5f) --> \_