What are the url parameters naming convention or standards to follow

Are there any naming conventions or standards for Url parameters to be followed. I generally use camel casing like userId or itemNumber. As I am about to start off a new project, I was searching whether there is anything for this, and could not find anything. I am not looking at this from a perspective of language or framework but more as a general web standard.

I recommend reading Cool URI's Don't Change by Tim Berners-Lee for an insight into this question. If you're using parameters in your URI, it might be better to rewrite them to reflect what the data actually means.

So instead of having the following:

/index.jsp?isbn=1234567890
/author-details.jsp?isbn=1234567890
/related.jsp?isbn=1234567890

You'd have

/isbn/1234567890/index
/isbn/1234567890/author-details
/isbn/1234567890/related

It creates a more obvious data structure, and means that if you change the platform architecture, your URI's don't change. Without the above structure,

/index.jsp?isbn=1234567890

becomes

/index.aspx?isbn=1234567890

which means all the links on your site are now broken.

In general, you should only use query strings when the user could reasonably expect the data they're retrieving to be generated, e.g. with a search. If you're using a query string to retrieve an unchanging resource from a database, then use URL-rewriting.

There are no standards that I'm aware of. Just be mindful of IE's URL length limit of 2,083 characters.

Standard for URI are defined by RFC2396.
Anything after the standardized portion of the URL is left to you.

You probably only want to follow a particular convention on your parameters based on the framework you use.
Most of the time you wouldn't even really care because these are not under your control, but when they are, you probably want to at least be consistent and try to generate user-friendly bits:

• that are short,
• if they are meant to be directly accessible by users, they should be easy to remember,
• case-insensitive (may be hard depending on the server OS).
• follow some SEO guidelines and best practices, they may help you a lot.

I would say that cleanliness and user-friendliness are laudable goals to strive for when presenting URLs.
StackOverflow does a fairly good job of it.

I use lowercase. Depending on the technology you use, QS is either threated as case-sensitive (eg. PHP) or not (eg. ASP). Using lowercase avoids possible confusion.