Software Engineering Data Dictionaries (1 Viewer)

[mickeyd_357]

Hi I was just wondering if anyone could explain to me how to calculate the number of bytes needed for storage for data dictionaries. I saw a question from the 2020 SDD hsc exam (Q25). I am confused about how to calculate it for string, integers and other data types. Why is an integer 4 bytes? How many bytes is a letter?
Any help would be greatly appreciated

 

[Socialism]

As a rule of thumb, one character is one byte. The data dictionary on page 8 might give you some information as well.
They also specify that booleans are 1 bit (which doesn't really make sense... i can't remember exactly why but my teacher was quite annoyed 2 weeks ago when he saw)
and that date/time is 4 bytes

 

[Socialism]

actually, i've got no idea because the internet is saying different things than the course specs
check with your teacher
i would assume that the course specs are what they base the correct answers off, but it might be rough if you get a marker who isn't aware that the course specs say these apparently weird things

 

[Socialism]

it might be a python thing? if python integers aren't fixed size (google this), maybe you're supposed to assume it's 1 byte?
the four bytes fixed-size integer seems to be a C suite (& other languages) thing, whereas in our course we only learn python

so that could be an explanation for that

 

[mickeyd_357]

ok thanks

 

[dav53521]

They also specify that booleans are 1 bit (which doesn't really make sense... i can't remember exactly why but my teacher was quite annoyed 2 weeks ago when he saw)

Just FYI a singular bit can be used to represent a boolean as 0 is used to represent false and 1 is used to represent true. However, a lot of languages use a byte for a boolean as we don't really work in bits anymore, but they still use 0 and 1 to represent false and true