What is the Web Layer?

The web layer brings together the design and code instructions in a way that a user can understand on a web page. These pages are written in HTML (normally using CSS too because this enables easier control of the look of the site) and are displayed in a browser.

Glossary

Making the simple complicated is commonplace; making the complicated simple, awesomely simple, that’s creativity. Charles Mingus

Sometimes projects can be confusing if they get a bit technical. As a not really very technical product manager, I’ve found out some handy bits of  info that could be useful for other PM’s and pulled them all into a glossary which I hope is useful.

What are stored procedures?

Stored procedures

These are used when a developer is using the N-Tier architecture.

Stored procedures are scripts that call set pieces of information from the database.  They help to make development easier because it means that that bit of code can be called upon again and again instead of writing new code every time that particular bit of information is required.

I found a baking analogy quite useful when learning about stored procedures. So if you imagine that creating a web page is like making a tart, (stay with me here…), the stored procedures are like little recipes for all of the separate parts and using all of them together makes the whole dish. So, there would be a stored proc for the pastry, one for the filling and one for the sauce to pour over the top. Then if someone else needed the pastry one, they can just call that instead of writing that bit of code again. But they would need a different stored procedure if a different filling was required.

Stored procedures are called by services which sit in the Services Layer above. The overview below indicates the order of the data flow.

What is URL rewriting?

URL rewriting

This is a very effective way of improving SEO. It takes the title of the page and automatically inserts it into the URL so that the URL, title and H1 all match and you get loads of traffic! Woo woo!

What is SQL?

SQL

This is the name of the database itself and the language used to communicate with it.  It is where the stored procedures pull data from.

It is usually administered by a DBA who knows how to get useful information from it by creating queries that look like this:

SELECT DISTINCT customers.customer_id, customers.customer_name

FROM customers INNER JOIN orders ON customers.customer_id = orders.customer_id

Therefore it’s handy to make friends with the DBA.

Note:  Apparently if you’re a ‘proper’ tecchie, the correct way to pronounce this is ‘Sequel’, not S-Q-L. (Otherwise they’ll laugh at you secretly.)

What is the Services Layer?

Services Layer

This layer sits between the Web and Data Access Layers in the N-Tier process. It contains scripts called services which tell the Data Access Layer which stored procedures to call from the database.

What is N-Tier?

N-Tier

This is the name of the process of developing in ASP.NET, using a programming code ( like C# for example) to tell the web pages what to display and the database language SQL to query the database. The process uses three ‘Layers’ in between the browser and the database.

The top layer is the Web Layer and this is the interface between man and machine.  The data on the web pages and the way they function is achieved by the Services Layer calling the correct stored procedures from the database.

Beneath this is the Services Layer, which contains the scripts that tell the Data Access Layer what information to pull from the database.

The diagram below from Wikipedia is a pretty useful overview. I’ve put a breakdown of what’s in each layer on the right.

What’s the data access layer?

Data Access Layer

This is where the stored procedures are held and they pull the relevant information from the database.

What’s a control?

Control

This is a bit of code that tells a part of a webpage how to act. Controls are usually used for bits of code that need to be on several pages, so for example, it might be a ‘Help’ box that needs to appear on a few different pages of the site. The designer can then use the control to easily insert the box on different pages without worrying about the styling and the information called.

What is C#?

C# (C Sharp)

This is the name of (apparently the best) coding language. It looks a bit like this:

class LINQQueryExpressions
{
    static void Main()
    {

        // Specify the data source.
        int[] scores = new int[] { 97, 92, 81, 60 };

        // Define the query expression.
        IEnumerable<int> scoreQuery =
            from score in scores
            where score > 80
            select score;

        // Execute the query.
        foreach (int i in scoreQuery)
        {
            Console.Write(i + " ");
        }           
    }
}
// Output: 97 92 81

…and communicates all the way between the Web Layer and Data Access Layer. Developers use programmes like Microsoft Visual Studio to write their code.