Overview
In some cases, data types used internally in LN differ from standard formats as used in the BIDs. In a number of cases an automatic data type conversion is done, to avoid programming efforts and risks of errors.
Standard conversions are available for:
- Boolean
- UTC date/time and date
- Enumerate
- Text
- Number to string and vice versa
- Doubles
- XML.
Each of the listed item is explained later. No other standard conversions are available.
Note: Standard conversions can be overruled by implementing a
conversion hook. So when defining a conversion hook, the standard data type
conversion is not executed.
Just like calculations, conversion hooks impact performance, because a filter on a calculated value cannot be delegated to the DBMS. Instead too much data is read from the database, and ‘postfiltering’ is done after calculating the public attribute value, which is an expensive process. So if possible, avoid conversion hooks, especially on enumerate values.