Debrief Homework Import data from the text file CanadianUniversities06.txt into a temporary table. What is the primary key for this table? Construct an APPEND query to copy select data from this table into the appropriate fields in table tbl_Schools http://www.cse.msu.edu/~cse103 U:/msu/course/cse/103

Relational Databases What are entities? How are they stored? What are attributes? How are they stored? What is a 1:N relationship? M:N relationship? 1:1 relationship? What is a foreign key? http://www.cse.msu.edu/~cse103 U:/msu/course/cse/103

Relationships in the music_Day07 database Copy the music_Day07 database and open it in Access Identify relationships between the tables. How did you find each? Classify each relationship as M:N, 1:N, or 1:1. http://www.cse.msu.edu/~cse103 U:/msu/course/cse/103

Contacts Database The database contacts.mdb currently consists of a single table. We now need to accommodate a wide variety of phone data. How should we change the contacts database to best handle this new data? What type of relationship is needed? (Assume one phone number is associated with exactly one person.) http://www.cse.msu.edu/~cse103 U:/msu/course/cse/103

Four Steps to Redesign the contacts database Design the new tbl_Phones table Fields, Names, Datatypes We will make the assumption that a phone number can belong only to one person (without this assumption, we would need several extra steps) Transfer the existing data to the new table and CHECK YOUR RESULTS Delete the unneeded column(s) from the original table (But once they’re gone…) Enter any new phone information http://www.cse.msu.edu/~cse103 U:/msu/course/cse/103

First Step Design the new tbl_Phones table Fields, Names, Data types Remember: This table is to describe the “Phones” entity, not People What is an appropriate primary key? What foreign key(s) might you need to use? In a relational database, 99% of the time, when you make a new table, it should have a foreign key from at least one other table http://www.cse.msu.edu/~cse103 U:/msu/course/cse/103

Next Steps Transfer the existing data to the new table using action queries CHECK THE RESULTS!!! Delete the unneeded column(s) from the tbl_People table (AFTER checking) Enter any new phone information in the new table tbl_Phones http://www.cse.msu.edu/~cse103 U:/msu/course/cse/103

Redesign debrief What is the primary key in the new tbl_Phones table? Is there a foreign key in the tbl_Phones table? If so, what one? How was the data transferred? What column(s) needed to be removed? What difficulties were encountered? http://www.cse.msu.edu/~cse103 U:/msu/course/cse/103

Updating database exercise Note the size of your contacts database file now and again after these steps. Update the data type and length of each field in both tables to what is actually needed to accommodate the data. Use HELP to find out how to compact a database. Compact your contacts db. How was the size of your file affected? http://www.cse.msu.edu/~cse103 U:/msu/course/cse/103

musicDay07 database In classical music and jazz, many artists perform together on a single album but do not actually form a group. What type of relationship does this imply exists between artists and albums? How does our database musicDay07.mdb accommodate this? How can we change the database to handle this situation? http://www.cse.msu.edu/~cse103 U:/msu/course/cse/103

Four Steps to Redesign the musicDay07 database Make a new table tbl_PerformsIn Transfer the existing data into the new table and CHECK THE RESULTS Delete the redundant info from the original tables (AFTER checking) Enter any new data into the new table This new data is in the Classical_Music07.xls file in today’s AFS space (see next slide) http://www.cse.msu.edu/~cse103 U:/msu/course/cse/103

Homework Work on the classical_music07.xls import What problems do you run into? How can you solve these? If you can’t finish, come prepared to discuss your problems on Day 08. Check the link on today’s classwork page for homework to do for Day 08 Transfer addresses like phones Finish redesigns from class (Phones, PerformsIn) http://www.cse.msu.edu/~cse103 U:/msu/course/cse/103