There is a distinction between the table (data definition and data container) and the data (the contents of a table). The table definition describes the identification information, data structure, validation rules, storage, and retrieval of the data that is stored in the table (container). The definition is defined by the design and can only be changed by a developer. The data is the variable content that originates from user activities. The place where we can see the data explicitly referenced independently of the table as a definition of structure is in the Permissions setup data. In the following screenshot, the data is formally referred to as Table Data:

The table is not the data, it is the definition of data contained in the table. Even so, we commonly refer to both the data and the table as if they were one and the same. That is what we will do in this book.

All permanent data must be...

Now we can take our knowledge of tables and expand our WDTU application. Our base Radio Show table needs to be added to and modified. We also need to create and reference additional tables.

Although we want to have a realistic design in our sample application, we will focus on changes that illustrate features in NAV table design that the authors feel are among the most important. If there are capabilities or functionalities that you feel are missing, feel free to add them. Adjust the examples as much as you wish to make them more meaningful to you.

In Chapter 1, Introduction to NAV 2017, we created the Radio Show table for the WDTU application. At that time, we used the minimum fields that allowed us...

For this discussion, we will divide table types into three categories. As developers, we can change the definition and the contents of the first category (the Fully Modifiable tables). We cannot change the definition of the base fields of the second category, but we can change the contents (the Content Modifiable tables) and add new fields. The third category can be accessed for information, but neither the definition nor the data within is modifiable (the Read-Only tables).

The following tables are included in the Fully Modifiable tables category.

The Master Data...

1. Which of the following is a correct description of a table in NAV 2017? Choose two:

a) A NAV table is the definition of data structure

b) A NAV table includes a built-in data entry page

c) A NAV table can contain C/AL code but that should be avoided

d) A NAV table should implement many of the business rules of a system

2. All primary keys should contain only one data field. True or false?
3. It is possible to link a NAV table to a table outside of the NAV database using what property? Choose one:

a) DatabaseLink

b) ObjectPointer

c) LinkedObject

d) C# Codelet

4. System tables cannot be modified. True or false?
5. Which of the following are table triggers? Choose two:

a) OnInsert

b) OnChange

c) OnNewKey

d) OnRename

6. Keys can be enabled or disabled in executable code. True or false?
7. Because Setup tables on contain one record, they do not need to have a primary key. True or false?
8. Table numbers intended to...

In this chapter, we focused on the foundation level of NAV data structure: tables and their internal structure. We worked our way through the hands-on creation of a number of tables and their data definitions in support of our WDTU application. We briefly discussed Field Groups and how they are used.

We identified the essential table structure elements including Properties, Object Numbers, Triggers, Keys, and SumIndexFields. Finally, we reviewed the several categories of tables found in NAV 2017.

In the next chapter, we will dig deeper into the NAV data structure to understand how fields and their attributes are assembled to make up the tables. We will also focus on what can be done with Triggers. Then we will explore how other object types use tables, working towards developing a fully featured NAV development toolkit.