prmryky

Questão	Responda
Primary Key- A unique identifier foreign Key- used as a link to other tables	Data structures made up of files files made up of records records made up of fields
Flat file database single table inefficient anomalies happen insertion update deletion	Relational Database more than 1 table links tables in a relationship key links tables
validation 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 data	Types 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

Resumo de Recurso

	Criado por dylan murphy quase 7 anos atrás