you could always make the value pluggable, going with Unknown for now, and then down the line if we want, we could add an "ONNULL" value to the parser that sets it.
2012/6/8 Prasanth J <[email protected]> > Thanks Alan and Dmitriy for your thoughts. > > I think we have two different approaches now. > > In one approach, if we encounter a null in dimension values we can just > label it as "unknown" and use "NULL" string to represent rollups. Whereas, > in other approach, if we encounter a null in dimension values, use the null > value as such but use "*" or any other string for rollups. > > Both approaches looks good to me. Please let me know which one should I go > ahead with. > > Thanks > -- Prasanth > > On Jun 8, 2012, at 12:22 PM, Alan Gates wrote: > > > Option 1 (throwing an error) is bad. It violates "Pigs eat anything" > (see http://pig.apache.org/philosophy.html). > > > > Do we need to give users an ability to name this unknown column? Why > not just label it "unknown" and be done? > > > > Alan. > > > > On Jun 6, 2012, at 2:24 PM, Prasanth J wrote: > > > >> Hello everyone > >> > >> I would like to bring up this discussion about the ways for handling > NULL values in dimensions specified for cubing. For example, if we have a > dimension color with following values > >> > >> red > >> blue > >> null > >> green > >> > >> how do we differentiate if the null value represent rollup of all > colors values or actual null value? > >> > >> SQL way: > >> There are 2 ways in which SQL server analysis services handles null > values in dimensions > >> 1) Throw error when it encounters null values in dimension values > >> 2) Ignore error by adding the null values to UnknownMembers. By default > UnknownMembers will be named as "Unknown". The name for UnknownMembers can > also be specified by the user. > >> > >> Do we need to handle both ways in Pig? I think the first way (throwing > error) is pretty straightforward. > >> For the second way (ignoring error), what is the best way to provide > support for user specified name for UnknownMembers? > >> > >> Please share your thoughts about how we can handle this scenario for > different datatypes in Pig. > >> > >> Thanks > >> -- Prasanth > >> > > > >
