System Table in Navision

System Tables are created automatically by the Navision to manage system security and keys in Navision. There are eight system tables in Navision:
1) 2000000002 - User
2) 2000000003 - Member Of
3) 2000000004 - User Role
4) 2000000005 - Permission
5) 2000000053 - Windows Access Control
6) 2000000054 - Windows Login
7) 2000000006 - Company
8) 2000000203 - Database Key Groups

Relational Operators

This operator is used in a relational expression to test a relationship betweenthe term preceding it and the term following it, resulting in a Boolean value.

The relational operators are:·
= (equal to)·
< (less than)·
> (greater than)·
<= (less than or equal to)·
>= (greater than or equal to)·
<> (not equal to)·
IN (included in set)

Object-Oriented vs. Object-Based

C/SIDE is not object-oriented but object-based. This is an important distinction. In an object-oriented language or environment, a developer can create new types of objects based on the ones already in the system. In Microsoft Dynamics NAV, you can only create objects that are either tables, forms, pages, reports, dataports, XMLports, codeunits, or menu suite objects.Because there are a limited number of application objects, C/SIDE works faster and more efficiently. The greatest benefit is the Stability.

System Defined Variables

C/SIDE automatically declares and initializes a number of variables that you can use when you develop applications. The following details describes the system-defined variables.

Rec
When a record is modified, this variable specifies the current record, including the changes that are made.
xRec
When a record is modified, this variable specifies the original values of the record, before the changes.
CurrForm
This variable specifies the current form. You can access the controls of the form through this variable and set the dynamic properties of the form and its controls.
CurrReport
This variable specifies the current report.
RequestOptionsForm
This variable specifies the request options form for the current report.

Add a Function to a Codeunit

1. Select the C/AL Editor, click View, and then click C/AL Globals.

2. In the C/AL Globals window, click the Functions tab.

3. Enter a name for each function that you want to add.

4. Click Locals to define the parameters, return value, local variables, and text constants in the C/AL Locals window.

5. In the C/AL Locals window, click the Parameters tab and specify the calling method, name, and data type of each parameter. You can also specify a subtype and a length, but this is optional.

The calling method can be specified as Var, which means that the parameter is passed by reference rather than by value. The value of a variable can only be changed by a function when it is passed to the function by reference. When the parameter is not specified as Var, only a copy of the variable is passed to the function. If the function changes that value, the change only affects the copy and not the variable itself.

If the type that you select corresponds to an application object, you must also add a subtype, that is, the name of a specific object in the database. If you select text or code you have to define a length. The default length is 10 characters for code and 30 characters for text.

6. In the C/AL Locals window, click the Return Value tab and specify the return value for your new function. Enter a name for the return value and select a data type from the drop-down list. If the data type is text or code, you can also select a length.

7. n the C/AL Locals window, click the Variables tab and define local variables.

8. In the C/AL Locals window, click the Text Constants tab and define text constants for the function.