I've dig the database here and didn't found any answer for my question. What is a standard for a php programmer to know? I mean, literally, what group of language functions, mechanisms, variables should person know to consider oneself a (good) php programmer? (I know 'being good' is beyond language syntax, still I'm considering syntax of plain php only) To give an example what I mean: functions to control http sessions, cookies functions to control connection with databases functions to control file handling functions to control xml etc.. I omit phrases like 'security' or 'patterns' or 'framework' intentionally as it applies to every programming language. Hope I made myself clear, any input appreciated :) Note: Michael J.V. is right claiming that databases are independent from language, so to put my question more precisely and emphasise differences: Practises or security, are some ideas to implement (there is no 'Pattern' object with 'Decorator()' method, is there?) while using databases means knowing a mysqli and a set of its methods.