When you are creating custom scripts or views you can use a parameter that converts all instances of that name to what it contains and set it to what the project name is.
The bonus of this is that you can change the name of fields and tables, without having to change anything in the script.
Additionally it makes the fields that are used known in the data linage view.
In essence you can use parameters every time you have this screen.
You get that every time you do something custom. Below are a list of features that use this, or variations of this screen:
- Custom Views
- Script Actions
- Stored Procedures
- User defined functions
- Custom Table Inserts
- Custom Field transformations
- Custom Data selection rules
- Semantic Custom Scripts
- Calculated Measures
- Derived Measures
- Script Commands
- Dynamic Project variables
So you can use it in many ways.
Add parameters to a view or script
Say you want to join two tables via a left join, such as explained here. You start by either copying in a already working script, or you write the first lines such as below.
The next step is to drag and drop some fields from a table you want to use. Notice that they are added in the parameter area.
Keep it on until you have pulled in all the fields you want, from the tables you want. The next step is to pull in the tables itself. It is done the same way, only remember to change the variant. Mostly we use Valid table.
The next step is to join the two tables and that poses a problem. When you try to pull in the field from the other table you will get the following notification. Press on the Rename button and give it a destinctive name.
You can also change it manually, by marking the Name area and just typing in its name.
When all the fields are added you will have a long list of parameters. Consider giving all fields a unique name, so no fields have the same names.
The final look of this script could be like this. Even though it is not completely necessary i use only unique fields.
Here is how its translation looks.
If you forgot a field and changed it in the name area, but not the script you will get the following notification.
The smart thing is that you now can do changes in the other tables and they will be noticed and keep working in the script. Below i change the names of two fields in my view.
Even before i have deployed the changes the names have changed in the code. It knows what table each field comes from, so it changes the correct one.
This applies to all the variations i added.