Rental List

Renter Phone Equipment ID Number Daily Rate Date Date
ABC Inc. 478-1822 LCD Projector (VGA) 2021 $50 April 1 April 5
ABC Inc. 478-1822 Projection Screen 1854 $10 April 1 April 5
Kerrville ISD 218-1923 LCD Projector (SVGA) 2024 $60 April 14 April 16
Ballantine Inc. 424-9911 LCD Projector (VGA) 2021 $50 April 20 April 22
Kerrville ISD 218-1926 Dell Laptop 2038 $40 April 4 April 6
Sammy's Pest Service 499-1829 LCD Projector (VGA) 2021 $30 April 7 April 9
Anarchists United LCD Projector (VGA) 2021 $45($50) April 12 April 15
AVE Rentals LCD Projector (VGA) (internal) (none) April 16 April 19
Ballantine Inc. 424-9911 LCD Projector (VGA) 2021 $50 April 20 April 22
ABC Inc. 478-1822 LCD Projector (VGA) 2021 $50 May 1 May 3



Issues identified with the table:

Renter Phone Equipment ID Number Daily Rate Date Date
ABC Inc. 478-1822 LCD Projector (VGA) 2021 $50 April 1 April 5
ABC Inc. 478-1822 Projection Screen 1854 $10 April 1 April 5
Kerrville ISD 218-1923 LCD Projector (SVGA) 2024 $60 April 14 April 16
Ballantine Inc. 424-9911 LCD Projector (VGA) 2021 $50 April 20 April 22
Kerrville ISD 218-1926 Dell Laptop 2038 $40 April 4 April 6
Sammy's Pest Service 499-1829 LCD Projector (VGA) 2021 $30 April 7 April 9
Anarchists United LCD Projector (VGA) 2021 $45($50) April 12 April 15
AVE Rentals LCD Projector (VGA) (internal) (none) April 16 April 19
Ballantine Inc. 424-9911 LCD Projector (VGA) 2021 $50 April 20 April 22
ABC Inc. 478-1822 LCD Projector (VGA) 2021 $50 May 1 May 3

Problems with this table:

  This cell holds more than a single value. A database table will not allow more than one value to be stored.
  Entries in these cells are not the same kind as the rest of the column. Each column must have a defined data type.
  These two columns have the same name. The creator of the list knew that the first column is the start date and the second is the end, but identical column names are invalid in a database.
  These rows are duplicates. A database table is not allowed to have two rows that are completely identical.



Organized as a Database

Below you'll find the information from the list above reconstructed to be used in a database. Note that a great deal of information has been added and that what started out as a single table has now been transformed into three. This was done through a process called normalization. In the next section you'll learn how some of the problems we see in the list above can be identified and overcome.

Customer List

Customer ID Customer Phone Number Street City State Zip Code
101 ABC Inc. 478-1822 123 Skylark Way Austin Texas 78745
102 Kerrville ISD 218-1923 2312 Main Street Kerrville Texas 76543
103 Sammy's Pest Service 499-1829 3756 North I-35 Austin Texas 78722
104 Anarchists United 477-9863 3465 Avenue D Austin Texas 78765
105 Ballantine Inc. 424-9911 5400 Grover Austin Texas 78767

Equipment List

Equipment ID Equipment Description Rental Rate
1854 Projection Screen $10
2021 LCD Projector (VGA) $50
2024 LCD Projector (SVGA) $60
2038 Dell Laptop $40

Rental List

Transaction ID Customer ID Equipment ID Start Date End Date
5001 101 2021 April 1 April 5
5002 101 1854 April 1 April 5
5003 102 1824 April 15 April 16
5004 102 2038 April 15 April 16
5005 103 2021 April 7 April 9
5006 104 2021 April 12 April 15
5007 105 2021 April 20 April 22
5008 101 2021 May 1 May 3