Hi, Andrew, It appears that the packed option might be a more reasonable one. You can pack up to 32 boolean flags in a 32-bit integer (ibis::INT or ibis::UINT). The parser understands "packedflags & 0100101001" as a bitwise expression (following C/C++ definition of bitwise operations between integral types). However, the constant 0100101001 would be parsed as a decimal integer. One may prefix the number with 0x (or 0X) for a hexadecimal number, but there is not way to input a binary number.
Please feel free to let us know if you encounter any problems. John On 8/31/2009 11:26 AM, Andrew Olson wrote: > Hi. > I'm considering creating a table using FastBit that has many boolean > columns, but it appears that the 8 bit char types are the most compact > format available. I could pack them into an unsigned long int, rather > than store them as separate shorts, but queries on such a column > (e.g., "packedflags & 0100101001 != 0") would not be able to take > advantage of the index. > > I have 2 questions. > 1. Are queries like that even possible in FastBit? > 2. Is there a space and time efficient way to represent and query > these boolean variables? > > Thanks, > Andrew > _______________________________________________ > FastBit-users mailing list > [email protected] > https://hpcrdm.lbl.gov/cgi-bin/mailman/listinfo/fastbit-users _______________________________________________ FastBit-users mailing list [email protected] https://hpcrdm.lbl.gov/cgi-bin/mailman/listinfo/fastbit-users
