SUNY Geneseo Department of Mathematics

Database Lab Day 1

Friday, April 29

Math 230 02
Spring 2016
Prof. Doug Baldwin

Return to List of Lectures

Previous Lecture

Misc
- Extended Math Learning Center hours for finals
  - Opening 9:30 (instead of 10:30) AM weekdays
  - 7:00 - 10:00 PM Sunday, May 8
- Solution to exam 2 available on “Exercises” page
- Final
  - Sample exam from last semester available on “Exercises” page
  - Friday, May 6, 8:00 AM
  - In our classroom
  - Comprehensive, but emphasizing material since 2nd hour exam (e.g., vectorization, 3D arrays, images, cell arrays, strings, files, etc.)
  - Designed for 2 hours, you’ll have 2 1/2 +
  - Rules and format similar to hour exams
  - Donuts and cider
- SOFIs
  - Helpful to me in planning future offerings of this course, especially comments on text
  - 9 filled out so far!
  - But more would be welcome

Questions?

Projection vs selection?

Projection picks 1 or more columns from relation
Selection picks one or more rows

Examples:

>> load database
>> mathContributions
mathContributions = 
    'Isaac Newton'         'Calculus'               [1666]
    'Gottfried Leibniz'    'Calculus'               [1675]
    'Kurt Goedel'          'Incompleteness'         [1931]
    'Alan Turing'          'Computability'          [1936]
    'John von Neumann'     'von Neumann Algebra'    [1930]

>> % Example projection: project column 3 from mathContributions
>> % Expect 1 column of dates, as a cell array (since it's a smaller relation)
>> project( mathContributions, [3] )
ans = 
    [1666]
    [1675]
    [1931]
    [1936]
    [1930]
>> % Example selection: select all rows with "calculus" in
>> % column 2 from mathContributions
>> % Expect 1st 2 rows as new cell array
>> select( mathContributions, 'Calculus', 2 ) 
ans = 
    'Isaac Newton'         'Calculus'    [1666]
    'Gottfried Leibniz'    'Calculus'    [1675]

Database Lab
Next
- Lab day
- No reading

Next Lecture