Let's see how metadata injection works through a very simple example. Suppose that you have an Excel file with sales data. There are several sheets in the file, but only one has the data you want to read. The name of the sheet is not fixed, so you have it in a Kettle variable. The quick solution to read the spreadsheet would be to explicitly declare the sheet name.
Unfortunately, PDI is not prepared to put a field or variable as the name of the sheet. Which other options do you have? As you know, the Sheet tab in the Excel configuration window can be left empty and PDI will read the sheets anyway. However, this would cause an error as, by default, PDI reads all the sheets, and in this case, the rest ...
