Domain Modeling

Domain modeling is the process of creating a conceptual model in code for a specific problem. A model describes the various entities, their attributes and behaviors, as well as the constraints that govern the problem domain. An entity that stores data in properties and encapsulates behaviors in methods is commonly referred to as an object-oriented model.

A domain model that’s articulated well can verify and validate the understanding of a specific problem among various stakeholders. As a communication tool, it defines a vocabulary that can be used within and between both technical and business teams.

Define a constructor and initialize properties

To define the same properties between many objects, you’ll want to use a constructor function. Below is a table that summarizes a JavaScript representation of an EpicFailVideo object.

Domain modeling is the process of creating a conceptual model for a specific problem. And a domain model that’s articulated well can verify and validate your understanding of that problem.

Here’s some tips to follow when building your own domain models.

When modeling a single entity that’ll have many instances, build self-contained objects with the same attributes and behaviors.

Model its attributes with a constructor function that defines and initializes properties.

Model its behaviors with small methods that focus on doing one job well.

Create instances using the new keyword followed by a call to a constructor function.

Store the newly created object in a variable so you can access its properties and methods from outside.

Use the this variable within methods so you can access the object’s properties and methods from inside.

Tables

There are several types of information that need to be displayed in a grid or table. For example: sports results, stock reports, train timetables.

What’s a Table?

A table represents information in a grid format. Examples of tables include financial reports, TV schedules, and sports results.

Basic Table Structure

The `

` element is used to create a table. The contents of the table are written out row by row. `` You indicate the start of each row using the opening `` tag. (The tr stands for table row.) It is followed by one or more <`td>` elements (one for each cell in that row). At the end of the row you use a closing `` tag. `` tag. **Table Headings** `` The headings of the table should sit inside the `` element. `` The body should sit inside the `` element. `` The footer belongs inside the `` element. **Old Code: Width & Spacing** There are some outdated attributes which you should not use on new websites. You may, however, come across some of them when looking at older code, so I will mention them here. All of these attributes have been replaced by the use of CSS. The width attribute was used on the opening `

` Each cell of a table is represented using a `	` element. (The td stands for table data.) At the end of each cell you use a closing `	` The `	` element is used just like the `	` element but its purpose is to represent the heading for either a column or a row. (The th stands for table heading.) Spanning Columns The colspan attribute can be used on a `	` or `	` element and indicates how many columns that cell should run across. Spanning Rows The rowspan attribute can be used on a `	` or `	` element to indicate how many rows a cell should span down the table. Long Tables There are three elements that help distinguish between the main content of the table and the first and last rows (which can contain different content). These elements help people who use screen readers and also allow you to style these sections in a different manner than the rest of the table (as you will see when you learn about CSS). `

` tag to indicate how wide that table should be and on some opening `

` and `

` tags to specify the width of individual cells. The value of this attribute is the width of the table or cell in pixels. The columns in a table need to form a straight line, so you often only see the width attribute on the first row (and all subsequent rows would use that setting). The opening `` tag could also use the cellpadding attribute to add space inside each cell of the table, and the cellspacing attribute to create space between each cell of the table. The values for these attributes were given in pixels. **Old Code: Border & Background** The border attribute was used on both the `

` and `

` elements to indicate the width of the border in pixels. The bgcolor attribute was used to indicate background colors of either the entire table or individual table cells. The value is usually a hex code.