NULL Values

1
NULL Values

• NULL is not a blank or a zero
• NULL can mean
• missing data
• undefined data

2
Entering data

• MovieIDs for new movies should be much larger
  than 100000
• Enter data for new movies in datasheet view
• get data from the other members of your group
• should be entering about 8 new movies

3
Importing Data into Existing Table

• More external data is in the file added
  movies.txt in the Day 27 AFS space
• tab delimited text file
• Import into tbl_movies
• Field names must match
• See Access Help for instructions on how you
  Import or link a delimited or fixed-width text
  file

4
SQL View

• Where does the table you are querying appear in
  the SQL?
• Where do the columns you selected appear?
• How is criteria used to filter records?
• What happens if you change Driving Miss Daisy
  to Star Wars and rerun the query?
• How does Design change after you modify the SQL?

5
Update Queries

• Questions to ask about an update query
• How can I figure out which records should be
  changed?
• What change should I make in these records?
• What expression can I use to carry out this
  operation?
• Construct an update query to convert the
  two-digit years to four digit years

6
Bridge Task 1.0

• The first attempt at the 1.0 BT is outside of
  class time next week
• Use the Schedule a Makeup link on the CSE 103
  site map to schedule your BT
• You must have picture ID for the BT!

7
Bridge Task 1.0

• Import data
• Filter by form
• Select records from a table using a query
• Update data in a table using an action query
• View the SQL in a query

8
Backing up your database

• You should have a backup of your database before
  taking the BT
• Two options
• make all changes to your database before midnight
  the evening before -- snapshot.afs contains a
  backup
• use a ZIP disk to backup your data

9
Homework

• Import data for the Actors entity