Where we use Cell Definition in Query Designing

A cell is the intersection between two structural components. The term cell for the function Defining Exception Cells should not be confused with the term cell in Microsoft Excel. The formulas or selection conditions that you define for a cell always take effect at the intersection between two structural components. If a drilldown characteristic has two different characteristic values, the cell definition always takes effect at the intersection between the characteristic value and the key figure.

Use of cell definition:
When you define selection criteria and formulas for structural components and there are two structural components of a query, generic cell definitions are created at the intersection of the structural components that determine the values to be presented in the cell.

Cell-specific definitions allow you to define explicit formulas and selection conditions for cells as well as implicit cell definitions. This means that you can override implicitly created cell values. This function allows you to design much more detailed queries.

In addition, you can define cells that have no direct relationship to the structural components. These cells are not displayed and serve as containers for help selections or help formulas.

For example:
 
You have already implemented the sales order system in your company. You have given the reports to the end users including open order reports. 

User come and tell you that they want some special calculations for some particular customers. Say for example, in your report you have 5 customers like Nike, Coke, Philips, Sony and Microsoft. For your users requirement you need to provide some discount or giving some special exceptions for only Microsoft on 5th month only. Microsoft's 5th month detail is always come in our report at fifth column fifth row. 

For this scenario you can use have accurate column and row that you need to calculate. So here you can utilize the function Cell Editor to calculate for the particular column.

What is the use of Define cell in BeX & where it is useful?

We need two structures to enable cell editor in bex. In every query you have one structure for key figures, then you have to do another structure with selections or formulas inside.

Then having two structures, the cross among them results in a fix reporting area of n rows * m columns. The cross of any row with any column can be defined as formula in cell editor.

This is useful when you want to any cell had a diferent behaviour that the general one described in your query defininion.

For example imagine you have the following where % is a formula kfB/KfA * 100.

kfA kfB %
chA 6 4 66%
chB 10 2 20%
chC 8 4 50%

Then you want that % for row chC was the sum of % for chA and % chB. Then in cell editor you are enable to write a formula specifically for that cell as sum of the two cell before. chC/% = chA/% + chB/% then:

kfA kfB %
chA 6 4 66%
chB 10 2 20%
chC 8 4 86%