= Announcement: Changes in unit handling = SMW supports units of measurement for its numerical datatypes. This feature will change in the next major version of SMW (and in SVN before that). Read on if you use units in your wiki.
== Current behaviour == For all properties of numerical datatype, SMW considers anything that follows the actual number to be the name of a unit of measurement. This unit *is part of the value* i.e. all values are really pairs of a number and a unit (where the latter can be empty). SMW further supports custom conversion factors that allow linear conversions between input units. This also helps to standardise unit names. == Future behaviour == In the future, SMW will no longer silently accept every text that follows a number as a unit. In many cases, such texts would be input errors anyway. Instead, SMW will only accept units for which some custom conversion has been declared (this can always be done, even if they are the only unit). As a result, units turn into a feature for input pre-processing, and are no longer part of the actual value that is stored. SMW will treat all numerical values as plain numbers, not as pairs of numbers and units. The unit is added visually when displaying this number. == Consequences and required updates == The change will only affect you if (a) you use unit strings in your wiki, but (b) have not declared the units on a custom page. In most cases, this will really be input errors that are simply not noticed due to SMW's silence. If you really want such units to be accepted, you need to declare them on an according type page. For declared units and for numbers without units, no observable change will happen. Advantages: The internal handling of numbers becomes much easier. One column in the respective database table can go away, reducing the memory requirements of query answering. Queries and RDF export become simpler. Disadvantages: You cannot use multiple units with one property without having a linear conversion between them. Rare cases may require a property to be split in two (one for each of the incompatible units) or replaced by a Type:Record based property that encodes a pair of a number and a (unit) string. Moreover, changing the unit declarations will affect the interpretation of data that is stored in the database, but note that such changes lead to update jobs that will repair the input over time. ------------------------------------------------------------------------------ Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d _______________________________________________ Semediawiki-devel mailing list Semediawiki-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/semediawiki-devel
