Fichas
MLF-Databases (8)
Fichas del conjunto (23)
- 1databasesan organised collection of related data. It is possible to add, edit, manage and retrieve data from a database. the structure of a data base allows data to be found and used quickly
- 2fielda single item of data within a record
- 3recordconsists of a collection of related fields
- 4file (table)a collection of related fields
- 5key fielda key field uniquely identifies each record. no two records have the same data in their key field. also known as a primary key
- 6validationvalidation methods can ensure reasonable and sensible data is input in to a system
- 7range checkdata entered must be in a sensible range
- 8type checkensures that the data is od the correct type
- 9format/picture checkif the data has a particular pattern eg. postcode, then the input mask can be used to force the data to conform to the rule
- 10length checkthe length of the input is checked for the number of characters used
- 11presence checksome data has to be entered
- 12look up listif the data entered consists of a limited number of possible entries then the computer can compare entry with a list of allowed answers
- 13reportsa report is a printed document that contains data from the database, organised and analysed in a certain way.
- 14formsforms are used to make data entry more attractive and secure rather than entering data into raw tables
- 15uses of a data base (4)add, change or delete records
search for a particular record
sore the records into a given order
print reports about some aspect of the database - 16updating recordsrecords do not stay the same forever. they get updated at some point e.g. people get married and change their surname, add a new record if a new pupil arrives at school, delete an old record, edit existing record
- 17searching for dataone main use of a data base is to find information quickly
to search for information you use a query
a query specifies what records you are searching for and what fields from the records to display - 18simple query search(key word search) looks for data in one field
- 19complex query searchlooks at data with a multiple criteria
- 20wildcard charactersyou use a wild card search in a query for data that you only know part of. e.g. all the usernames beginning with 's' you might write like: surname LIKE "*S"
- 21sorting data and why sort data?results of queries can be presented in a sorted order e.g. alphabetical or in a numerical order
why: easier if lists are printed as reports
you can identify best customers by the amount they have spent - 22software methods for keeping data secure (3)passwords, access rights can be places on individual files, back-ups
- 23benefits of using a data base (6)fast access
easy to edit
validation
reports
sharing
security
Información
- Descripción
- year 10 ICT Fichas sobre MLF-Databases (8), creado por Alyina Alam el 04/02/2015.
- Creado por
- Alyina Alam
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- 2
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