CS 511 Design of Database Management System Homework 1 Due 2 00 PM CST on September 12 2007 NOTE Please submit a hard copy of your homework Bring it to the lecture table at the beginning of the lecture on 12th September 2007 The hard copy should be as clearly readable as possible You may be subtracted points for unreadability and ugly presentation I2CS Students You should email your solutions to the TA termehch uiuc edu in the pdf or the word format Please send your email with subject CS511 HW1 and solution file attached by 2PM UIUC time CST Problem 1 Relational Model 20 Pts Briefly mention two flaws of the relational data model Problem 2 Relational Model 30 Pts Scientists use multiple sensors to gather temperature information of a specific object in scientific observations in order to obtain exact result Each sensor observes temperature information every second and sends the data to the main server to be stored on specific times A sensor would sometime report nothing null value or wrong value due to the physical problems Scientists have to use data from all sensors to find out the most precise temperature at each time Hence they merge and take average of the observed data for each observation They also compute differences among data gathered in different times or compound them to see temperature behavior during longer time period One dimensional array is a good fit to represent this data Specify and formulate an exact data model to represent the data and an algebra that covers the required operations You could add additional data item s to the array structure in your model Problem 3 System R 30 Pts 30 Points In relational database management systems like system R when user does not assign any value to a column in a row it is tagged by especial value called null 1 Give two different interpretations of having a null value in a column of type Boolean 2 Logical conjunction AND and logical disjunction OR consider just true and false as their input and output values For each interpretation in previous part create a new truth table for those operations that includes null value Problem 4 R Tree Indexing 20 Pts High dimensional data is data whose number of dimensions is more than say 15 Briefly mention one disadvantage of using R Tree index for high dimensional data
View Full Document
Unlocking...