1. Erlang
2. Informix ODBC Driver (CSDK)
3. DSN for the Database

Go to https://erlang.org/ official website. Click on Download Erlang/OTP Select the OTP version according to the requirement (for ex: OTP 21.3 Windows 64-bit Binary File) Once the Erlang packages are downloaded Run the otp_win64_21.3 installer and follow the installation process.

https://www.youtube.com/watch?v=uhsIu-zP7Hs

Informix ODBC Driver comes with the Informix CSDK Package, and to install Informix ODBC Driver we will need to install Informix CSDK Package.

1. Open ODBC Data Source(64 bit)
2. Uder the User DSN tab click on the Add... button
3. Select the IBM INFORMIX ODBC DRIVER(64-bit) and click on Finish.
4. It will prompt IBM Informix ODBC Driver Setup Window
5. Under the General tab put Data Source Name and Description (optional)
6. Now, go to the Connection tab and fill all the required fields (which is nothing but the connection details for the Database)
7. After filling the details click on the Apply & Test Connection button to test the Database connectivity.
8. If connection gets successful click on Apply and then OK.
9. And That's Done! ☺️

Getting started with the odbc connection:

1> odbc:start().
      ok  

2> {ok, Ref} = odbc:connect("DSN=erldsn;UID=informix;PWD=", []).
      {ok,<0.83.0>}  

Create a table:

3> odbc:sql_query(Ref, "CREATE TABLE EMPLOYEE (RollNo integer,Name char  varying(20),GENDER char(1),PRIMARY KEY (RollNo))").
      {updated,0} 

Insert some data:

4> odbc:sql_query(Ref, "INSERT INTO EMPLOYEE VALUES(1, 'Pratishtha, 'F')").
      {updated,1}

Check what data types the database assigned for the columns:

5> odbc:describe_table(Ref, "EMPLOYEE").
      {ok, [{"RollNo", sql_integer},
            {"NAME", {sql_varchar, 20}},
            {"GENDER", {sql_char, 1}}]}

Use a parameterized query to insert many rows in one go:

6> odbc:param_query(Ref,"INSERT INTO EMPLOYEE (RollNo, NAME, GENDER) VALUES(?, ?, ?)"
                   [{sql_integer,[2,3]},
                    {{sql_varchar, 20},
                   ["John", "Sophie"]},
                   {{sql_char, 1}, ["M","F"]}]).
      {updated, 2}	

Fetch all data from the table employee:

7> odbc:sql_query(Ref, "SELECT * FROM EMPLOYEE").
          {selected,["rollno","name","gender"],
          [{1,"Pratishtha","F"},{2,"John","M"},{3,"Sophie","F"}]}

Associate a result set containing the whole table EMPLOYEE to the connection. The number of rows in the result set is returned.

8> odbc:select_count(Ref, "SELECT * FROM EMPLOYEE").
      {ok,undefined}

Informix odbc is not returning the numer of rows count.