Month: December 2005

I just came across the naming convention for a has_and_belongs_to_many relation’s join table.

If you have tables products and categories, which have a many to many relationship, a product can belong to many categories and a category can contain many products. What would you name the joining table, products_categories or categories_products.

Rails convention says use categories_products.

Rails assumes that a join table is named after the two tables it joins (with the names in alphabetical order). If you use some other name, you would need an additional declaration.

Unless there is a very compelling reason to do so, one should stick with the convention.
Reason: For maximum productivity don’t go against Rails’ philosophy “Convention over configuration”

I tried this with mySQL. Should work with other databases too.

If you have columns named “created_at” or “updated_at” of type datetime in your database table,
Rails will automatically insert the value of now( ), in the column “created_at” when a model corresponding to the table is saved in the database. Similarly it will automatically update the value of the column “updated_at” to the value of now( ), when a model is updated and saved to the database.

“created_on” and “updated_on”, of type date, display the same functionality.

One of the basic Rails philosophy is “Convention over Configuration”, meaning that rails has sensible defaults for a lot of aspects.

If the programmer follows these naming conventions a lot of functionality in the application gets built-in by default.

Normally embedded Ruby code (Erb) in views that does not generate any output, leaves empty blank lines in the generated HTML code. These are embedded ruby lines in rhtml files which begin with < % and not <%=. To avoid generating these empty blank lines, end the embedded ruby code with -%>, the others will be ended as %>. The extra minus sign (-) at the end, will suppress the blank lines.

Many times data entered on the screen by a user, or data fetched from the db, contains less than (<), greater than (>), ampersand (&) and quotes etc. These characters have special meaning in html. And if these are passed in the view as such, they may garble the browser display.

The h() method prevents these characters in strings from garbling the browser display. The h() method escapes them as html entities.

h() method in rails does the same thing as htmlentities() does in php.

Update [17th Jan 2006] I just learnt that long name of h() is html_escape()