Databases Flashcards
Components of a database?
Tables, queries, reports, forms
fields (and key field) , records, auto numbers, data types (number, text, date, currency)
What are queries used for?
To search for specific records
What is validation?
Acts as a limit on what can be entered into a field/cell eg price > £10 < £50
Validation: range check -what it does and an example?
Minimum and maximun value
eg price > £10 < £50
Validation: Type check -what it does and an example?
**Sets type of data **
eg prices, currency, quantity
Validation: **Prescence check **-what it does and an example?
Checks that the field has been completed
eg email, password
Validation: **Length check **-what it does and an example?
Checks the number of characters
eg a moble phone number (11 numbers)
Validation: **List/look up **-what it does and an example?
Lists options
eg Mrs, Mr, Miss etc, gender
Validation: **Input mask **-what it does and an example?
Sets format
eg post code, product code
What is a data redundancy?
Duplication of data in a database eg 2x adress
Why might data be inaccurate and what fafcts may this have?
- Wrong orders
- Human errors
- May be difficult to contact someone if their data is wrong
- Incorrect procedures may take place
What is a simultation?
Simulators replican real life scenarios using variables and mathematical rules
eg variables for turbulance - wind speed, no of passengers, type of plane, plane size
Benefits of simulators?
- Less risk to peeople (eg passengers)
- Prapares for different scenarios
- Less expensive in the ong run
Limitations of simulators?
- Doesn’t simulare the real pressure of a situation
- Can’t replicate every single situation and its not always accurate anyay
- Can be very expensive in the short term eg Sydney plane simulators are $30 million
Whats an expert system?
Replicates the knowlage from an expert eg NHS symptom checker
User enters information, they recieve a response based on their input eg if their wifi wasnt working, they’d be told to switch it on and off
