Flashcards
Computing
Flashcards do conjunto (13)
- 1What is a databaseA structured set of data held in a computer, especially one that is accessible in various ways.
- 2What is data in a database organised into?Files, records and fields
- 3What is a relational database?A relational database is a collection of data items organized as a set of formally-described tables from which data can be accessed or changed in many different ways without having to reorganize the database tables.
- 4Define records.Records are composed of fields, each of which contains one item of information. A set of records constitutes a file.
- 5What is a flat file?A database which is contained in a single table.
- 6Name a disadvantage that could occur in flat filesData duplication, Modification errors, ect.
- 7What is a primary key?A primary key is a special relational database table column designated to uniquely identify all table records
- 8What is the main features of a primary key?It must contain a unique value for each row of data. It cannot contain null values.
- 9What is a foreign key?A foreign key is a field (or collection of fields) in one table that uniquely identifies a row of another table or the same table.
- 10What is validation?Validation is an automatic computer check to ensure that the data entered is sensible and reasonable.
- 11What is a presence check?This checks to make sure that a field has not been left empty. Often, a required feild will be highlighted with a asterisk or contain the word 'required.'
- 12What is restricted choice?It gives the user a list of options to choose from and so limits the input to pre-approved answers.
- 13What is field length?
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- FlashCards sobre Computing, criado por Montserrat Simpson em 28-03-2017.
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- Montserrat Simpson
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