Karteikarten
Ohne Titel
Karten in diesem Stapel (8)
- 1TableA collection of related information
- 2RecordsA record is all of the data on one thing or person
- 3FieldA field is one piece of information on one person or thing
- 4Data TypeMultiple pieces of data that can be put into a database such as number, date and time.
- 5Field LengthMost databases have a default field length such as 50 characters. But can be less for pieces of information like a postcode.
- 6Primary KeyEvery single record in a database has something different too identify it and this is a Primary Key.
- 7Foreign KeyA foreign key is sued too link tables together and create a relationship. This a field in one table that is linked to a primary key in another table
- 8Referential KeyEvery foreign key has a matching value to its corresponding primary key. Referential integrity uses these too ensure there are no orphan records i.e this prevents you from deleting related records.
Informationen
- Beschreibung
- Karteikarten am Ohne Titel, erstellt von 11dvincent am 11/11/2014.
- Erstellt von
- 11dvincent
- Aufrufe
- 0
- Bewertung