ICT - Databases - Mindmap in GCSE ICT

Created by: lou9119
Created on: 24-04-16 11:32

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Databases
- - A database is an organised collection of related data that can be added, edited and managed.
- Data Types
  - Number integer i.e 43.
  - Number real i.e 43.25
  - Text or string i.e John Smith.
  - Curency
  - Boolean i.e yes
  - Lists
  - Picture
  - Sound
  - Video
- Files, records and fields
  - Field: A single data item.
    - Record: A collection of related fields.
      - File:A collection of related records, sometimes referred to as tables.
        Files, records and fields
        Field: A single data item.
        Record: A collection of related fields.
        File:A collection of related records, sometimes referred to as tables.
        
        Updating records is key, some examples in a school system are adding new records when a pupil joins, edit records if a pupil's information change and delete records when a pupil leaves.
        
        A KEY FIELD uniquely identifies a record. Meaning that no two records will have the same key field. The purpose of this is to be able to refer to an individual record using a single field.
      - Updating records is key, some examples in a school system are adding new records when a pupil joins, edit records if a pupil's information change and delete records when a pupil leaves.
    - A KEY FIELD uniquely identifies a record. Meaning that no two records will have the same key field. The purpose of this is to be able to refer to an individual record using a single field.
- Validation
  - -GIGO, checks are done to make sure the data inputted is correct.
    - Range check = data is within a sensible range.
    - Type check = data is of the correct type.
    - Length check = length of the input for the number of characters is used.
    - Look-up-list = data entered against a list of possible entries.
    - Picture or format check = data entered has a particular pattern.
    - Input mask = forces data to conform to a rule.
    - Presence check = ensures that certain data is present.
- Reports
  - - A printed document that contains data from the database, organised and analysed in a certain way.
- Calculated fields
  - - Not all data needed in a report may be presented from the database, For example a person's age changes every day and so if you want to use age in a report you must you a calculated field.
- Uses
  - Add, change or delete records.
  - Search for records.
  - Sort records in a given order.
  - Print reports.
  - Use the data for applications.
- Sorting
  - Alphabetical order for a register.
  - Order of marks in an exam.
  - Chronological order for D,O.B
  - Searching for Data
    - - By creating a query you can search for specific fields. This can be done by using a simple search (looking for data in only one key field) or a complex search (looking for data with multiple criteria.
      - Wildcard characters are used in a query to stand for any character you don't know exactly. For example you may search: Surname LIKE "S"
    - Operators can be used for this also. i.e =, , , AND, OR
- Benefits
  - Fast
  - Data integrity
  - Print reports
  - Shared on networks
  - Passwords
    - Method of AUTHEN-TICATION.
      - Acces rights also can be placed on a file to give either no right to access, read access or write access.
- Security and databases
  - If it is secure it cannot be destroyed, altered or get into unauthorized hands.
  - Physical security can be set in place too, locks, alarms, ID cards and biometric systems.
  - Backups
    - This can be done through removable media (memory stick) stored in a safe or made regularly.

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ICT - Databases

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