By Sam Ruby, Dave Thomas, David Heinemeier Hansson
Ruby on Rails is helping you produce fine quality, beautiful-looking net functions speedy. you consider growing the applying, and Rails looks after the main points. Tens of hundreds of thousands of builders have used this award-winning booklet to benefit Rails. it is a wide, far-reaching educational and reference that is instructed by means of the Rails middle crew. if you are new to Rails, you will get step by step assistance. in case you are an skilled developer, this e-book offers you the great, insider info you would like. Rails has advanced through the years, and this e-book has developed besides it. We nonetheless commence with a step by step walkthrough of establishing a true program, and in-depth chapters examine the integrated Rails good points. This version now provides new Ruby and Rails clients additional info at the Ruby language and takes extra time to give an explanation for key ideas all through. top practices on how you can practice Rails proceed to alter, and this version retains up. Examples use cookie subsidized periods, HTTP authentication, and lively Record-based kinds, and the e-book focuses all through at the correct solution to use Rails. also, this variation now displays Ruby 1.9, a brand new liberate of Ruby with titanic useful and function advancements.
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Extra resources for Agile Web Development with Rails (4th Edition - final)
The model is responsible for maintaining the state of the application. Sometimes this state is transient, lasting for just a couple of interactions with the user. Sometimes the state is permanent and will be stored outside the application, often in a database. A model is more than just data; it enforces all the business rules that apply to that data. For example, if a discount shouldn’t be applied to orders of less than $20, the model will enforce the constraint. This makes sense; by putting the implementation of these business rules in the model, we make sure that nothing else in the application can make our data invalid.
We’ll invoke that method a couple of times: def say_goodnight(name) result = 'Good night, ' + name return result end # Time for bed... puts say_goodnight('Mary-Ellen') puts say_goodnight('John-Boy') Having defined the method, we call it twice. In both cases, we pass the result to the method puts, which outputs to the console its argument followed by a newline (moving on to the next line of output). You don’t need a semicolon at the end of a statement as long as you put each statement on a separate line.
If you decide to use something else, it won’t be a major problem. You may have to make minor adjustments to any explicit SQL in our code, but Rails pretty much eliminates database-specific SQL from applications. If you want to connect to a database other than SQLite 3, Rails also works with DB2, MySQL, Oracle, Postgres, Firebird, and SQL Server. For all but SQLite 3, you’ll need to install a database driver, a library that Rails can use to connect to and use your database engine. This section contains links to instructions to get that done.