Databases

Question 1

what is a database

Answer 1

• A computerised system that makes it easy to
  Search
  Select
  Store information
• The digital equivalent of a paper filing system that you would have in a filing cabinet
• A collection of tables- like in excel, it is made up of columns and rows, each item in the databased is a record and each record is made up of several fields

Question 2

why would we use a database in forensics

Answer 2

• Databases help us catalogue information
• No database= ++hours
• NDNAD UK national DNA Database: hold files of 10% population, largest in world. The US equivalent contains only about 0.5% of the populations DNA on file.
• DNA of individuals and of unsolved crime stains
• NDNAD is officially called the UK National Criminal Intelligence DNA Database.
• Anyone sampled under PACE - Police and Criminal Evidence Act 1984, will have a sample of their DNA in the database, but it also contains samples of DNA found at crime scenes;

Question 3

advantages to NDNAD

Answer 3

• Time saving
  Can be left to run a search without someone watching over the process
  Can speed up a case if there is a match in the database
  Can be easily updated with new DNA
• Space saving
  Doesn’t take up an entire building
  Can have one database rather than lots of buildings full of files
• Consistent- accredited laboratories across the UK can access NDNAD so a criminal could commit a crime anywhere and leave their DNA at the scene and have a match to a crime elsewhere in the UK

Question 4

disadvantages to NDNAD

Answer 4

• Ethical- is it ethical to have all these samples of DNA in a database like this
• Out of date- older samples might not be as accurate as newer samples, should they still be in the database
• Completeness- the database doesn’t have everyone’s DNA in it so it may not find a match to a criminal- a database is only as good as the data it contains

Question 5

points to remember

Answer 5

• A database is only as good as the data it contains or the search terms used

Question 6

adding data

Answer 6

• Form
• Specific fields to include
• Notes or extra information
• Update to add new files
• You might not have all the information for the record you are adding but if you can fill in as many of the fields as possible then there is more chance to find a match when searching and cross referencing items
• Depending on what the database contains information on will depend what fields it needs for an item. Some databases may need to have additional fields added when newer items come out – thinking here particularly of technology
• Quality or quantity? – info needs to be accurate rather than having every field filled in badly.

Question 7

searching a database

Answer 7

• Specific
• Will search for exactly what you typed
• Will not include or exclude some items that humans might when looking at a record
• Might require some special terminology
• Keywords

Question 8

presenting results

Answer 8

• There are different ways data can be presented
• Could be dependent on the number of matches
• Only one match could show the entire record
• Several matches could present a list

Question 9

types of database

Answer 9

• Depending on what you need to use a database for will depends on the type of database you create
• could have a centralised database or distributed one, could be on site or across sites or in the cloud
• Could have relational database where tables within the database are linked or you might have an object- orientated one where each item is recorded is object rather than a person for example
• You may have an SQL (structured query language) based database or one that is unstructured

Question 10

process inside the database

Answer 10

• Initial search terms- lots of results
• Refine search terms- more specific results
• Sift through results manually- are they all a close enough match, do you need to discard any, further refinement?