Karteikarten
prmryky
Karten in diesem Stapel (3)
- 1Primary Key- A unique identifier foreign Key- used as a link to other tablesData structures made up of files
files made up of records
records made up of fields - 2Flat file database single table inefficient anomalies happen insertion update deletionRelational Database
more than 1 table
links tables in a relationship
key links tables - 3validation Reduce likelihood of erroneous rules to create procees of ensuring data entered into a database meets a certain rule or rule to reduce the input of erroneous dataTypes of checks
Presence- ensures that data must be entered in a field
field length-details the number of characters in a field
range check- used to ensure that data falls between two values
Restricted access check- used to limit the user entry to a list of acceptable values