Structures and links (Databases) Flashcards
What is a database used for?
To store information
Why are databases used?
They are used because they can be searched and sorted very efficiently and can allow many users to use the same information simultaneously
Tables in a database can be linked using what?
Primary and foreign keys
What is a relational database?
A database that contains more than one table
What is the main advantage of a relational database?
Helps avoid unnecessary duplication of data
What is a primary key?
A primary key is a field in a table that contains a piece of data that is unique for every record.
What is a surrogate key?
A surrogate key is a field in a table which has been created by the system to ensure that a unique field exists for every record.
What is a compound key?
A compound key combines more than one field in order to make a unique key
What is a foreign key?
What is its use?
A foreign key is a field in a table that is the primary key of another table.
will be used to cross reference information in tables
What is a data entity?
Data entity is something that information will be recorded about in a database.
Explain the three types of relationships?
One to One = An entity is related to one other entity
One to Many = An entity is related to more than one other entity
Many to Many = Many entities are related to many other entities
What is a user interface?
A user interface is what the user sees when using a program or application
How can the usability of forms be increased?
Using drop down menus to select an option
What is a query?
A query is when you extract information from a database using searching and sorting tools
