About Programming: Bash Scripts, Referential Integrity, PHP Rounding

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Programming From Scott Orgera, your About Programming Editor This week we learn how to make a pregnancy calculator in PHP for those folks either expecting a new arrival or just wanting to learn how to create a really cool counter program. We also delve into the database concept of referential integrity, explain how to create functions and subroutines in Linux Bash scripts, discuss the Require method in Ruby, and much more... Functions and Subroutines in Bash Scripts Even though Bash is a Linux shell, it has many of the capabilities needed to be a general purpose programming language, such as loops and conditional expressions. While-loops and For-loops are ways to execute a sequence of instructions multiple times. Functions are another method you can use to prevent code duplication. Search Related Topics:  scripts  functions  subroutines PHP Pregnancy Calculator In this PHP program we make a pregnancy calculator to tell parents to be exactly how pregnant they are in days and weeks, how long they have to wait until their due date, and what percentage of the pregnancy has passed. Search Related Topics:  pregnancy calculator  due date  gestation calculator Understanding Referential Integrity Referential integrity is a database concept that ensures that relationships between tables remain consistent. When one table has a foreign key to another table, the concept of referential integrity states that you may not add a record to the table that contains the foreign key unless there is a corresponding record in the linked table. It also includes the techniques known as cascading update and cascading delete, which ensure that changes made to the linked table are reflected in the primary table. Search Related Topics:  foreign keys  referential integrity  PHP: Rounding and Formatting Numbers Sometimes when you are rounding numbers you always want to round down. For example, if you are calculating how many people will fit in a boat safely, you can't carry .47 of a person, and you can't exceed the capacity. Therefore in this circumstance you would always round down. In PHP this is done with the floor () function. Search Related Topics:  rounding numbers  php basic functions  php math Related Searches Web Programming Rounding Programming in Java Due Date Calculator PHP Programming Featured Articles Color Tips for the Web Is the 'Require' Method Overlooked in Ruby? Open Source Tools for Game Creation Java: How to Generate Random Numbers The Making of the 2013 Mac Pro Poll: Do You Use HTML5 Email and URL Fields?   More from About.com Run Your First 5K Even couch potatoes can be ready for a 5K with just a couple months of training. Read more...> Help! I'm Too Busy Time and stress management tips to help you feel as though you have more time. Read more...>   Sign up for more free newsletters on your favorite topics You are receiving this newsletter because you subscribed to the About.com Programming newsletter. If you wish to change your email address or unsubscribe, please click here. About.com respects your privacy: Our Privacy Policy Contact Information: 1500 Broadway, 6th Floor New York, NY, 10036 © 2013 About.com   Advertisement