help wit my data structure

greedyisg00d

I have a useracct table where my primary key must be company_code. My problem is in each company there are sub users therefore I cannot create another user because it will cause duplication. This is my existing structure:

company_code(PK)
employee_name
username
password

Thanks

halojoy

id int not null auto_increment primary key
company_code(PK)
employee_name
username
password

Why you need company_code to be PRIMARY KEY?
I have never yet created one table
without using ID as PRIMARY KEY
.. and I probably never willl...

Sounds like you need another table:
Table company

company_id int not null auto_increment primary key
company_code
company_name

johanafm

This is not a problem of choosing an appropriate key, but rather one of database normalization.

Company code, if unique, can be primary key in a company table. Its employees should reside in an employee table, using some unique identifier as primary key.

table company

company_code	VARCHAR? PRIMARY KEY,
company name	VARCHAR(30),
postal address	...,
etc

table employee

id		INT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
fname	VARCHAR(30),
lname	VARCHAR(30),
company	SAME_AS_FOR_company_code_IN_COMPANY_TABLE
etc,
CONSTRAINT employee_of_FK
 FOREIGN KEY(company) REFERENCES company(company_code)

As for choosing a primary key. Some people never use anything but an artificial id, others stick to using real data as primary keys when applicable.
Personally I go with an artificial id if all I would otherwise have to use is a string, and I'm guessing your company_code is of type VARCHAR. Integers are easy to use and when looking at data it's immediately apparent that one id differs from another. Indexing integers is also easy for the db, while string indexing may require more bytes for the index.
But if I have a table storing entries in time for a company, event or whatever, and I don't have to deal with multiple entries for any given time, I'd stick with the multi column primary key (company_id, datetime), rather than create an artificial key. Neither way is wrong, it's a matter of personal preference. Although I'm certain you can find people who claims that either one of them is wrong.