Summary of 13 good habits of foreign PHP programmers_PHP Tutorial

These are the 13 good PHP coding habits listed in this article. If you have better suggestions, please post them in the comments at the end of this article. I like to seek knowledge
1. Use select to query information from the same database. When doing so, use a join statement to get all the information you need neatly at once instead of writing multiple mysql_query/while/mysql_fetch_array statements.

2. If you call a database connection in multiple files, create a connection.php file to save your connection variables, and include this file where needed.

3. For small projects, write all your functions in a file. If it is a large project, write them in objects, and then include this file where needed.

4. If your include files are out of control, you can create an include file that contains all the .inc files, and then include this include file where you need it.

5. Write documentation for your code. You will need it when you look at the code 3 months later.

6. Code layout, nothing is more important than readability.

7. Separate the logic and presentation layers.

8. When writing classes, make sure you know when is the best time to couple and when is the best time to extend.

9. The interface is your friend.

10. Breaking your code into models, views, and controllers is super cheating when projects get bigger.

11. Never output POST and GET data without stripping off the HTML tags.

12. Never trust input from the user, even if she is your mother.

13. Never repeat class names. Remember, never!