Flashcards
Databases
Flashcards do conjunto (18)
- 1Validationan automatic computer check to ensure that the data entered is correct
- 2VerificationEnsures that the data entered exactly matches the original source. There are two main methods of verification; double entry and proofreading data
- 3Double EntryEntering the data twice and comparing the two copies. This effectively doubles the workload .
- 4Proofreading DataTo read (copy or proof) in order to find errors and mark corrections.
- 5Check digitThe last one or two digits in a code are used to check the other digits are correct
- 6Format checkChecks the data is in the right format
- 7Length checkChecks the data isn't too short or too long
- 8Lookup tableLooks up acceptable values in a table
- 9Presence checkChecks that data has been entered into a field
- 10Range checkChecks that a value falls within the specified range
- 11Spell checklooks up words in a dictionary
- 12Database StructureDatabases are organised by fields, records and files
- 13Database Structure- Fielda single piece of data such as name, date of birth or telephone number
- 14Database Structure- Recordthis is one complete set of fields, for example one pupil's information
- 15Database Structure- Filethis is a collection of records, for example a school database
- 16Relational DatabasesA relational database has more than one table and the tables are linked using key fields.
(i.e. a library database - customer, book, lending) - 17Key Field (or primary key)A unique identifier for each record
- 18QueriesFinding data in the data base which has been requested by the user
(Uses OR, AND, NOT)