ICT and common misconceptions - A Practical Guide to Teaching Computing and ICT in the Secondary School - page 123

DATABASE SKILLS, KNOWLEDGE AND UNDERSTANDING: KEY
CONCEPTS, COMMON MISCONCEPTIONS AND HOW TO AVOID THEM
Some of the key concepts that need to be covered are:
• What databases are and the purpose of them. As with spreadsheets, databases
have been around longer than the computer programs we tend to associate
with them now. Giving pupils some examples of non-computerised databases
can help them with the concept of what a database is, and can lead usefully
into discussions on why computerising them has advantages.
• Real-world examples of computerised databases. Pupils may have used a
range of computerised databases without realising it, in school and at home,
so discussing these is helpful. Examples could be the school register system,
medical records and the contacts list on their mobile phone.
• Advantages and limitations of computerised databases. To illustrate the power
of computerised databases have examples with very large amounts of data, so
they can see the speed of sorting and searching with a computer database
program.
• Key terminology, including record, field, field heading, data types, sort,
search, query, report, form.
• Simple and complex searches, including use of Boolean operators.
• Good design of databases and how to create one.
• When to use and how to design forms and reports.
• Validation and verification.
Common misconceptions include:
• Confusion between 'data' and 'information'. People often interchange the two
words, but they have different, specific meanings and these need to be
understood by pupils. Insist they use the correct term.
• Conceptualising how a computer organises and retrieves data can be difficult.
Use of metaphors, such as a 'filing cabinet', can help.
• Using wrong data types when creating a database. Deciding when to use
alphanumeric rather than numeric, or date rather than numeric requires
pupils to think carefully about the purpose of the database, and the data it
will use. Encourage them to discuss this with peers.
• Using wrong field headings when creating a database. This requires thought
at the design stage. One common error is to use 'age' as a field heading on a
database on people, when they should use 'date of birth'. Discussing how this
avoids the need to keep updating the database is worthwhile.
• GIGO (Garbage In Garbage Out). Pupils need to understand that if the data
entered is incorrect, then the outputs will be incorrect too. They need to be
taught to proofread the data on entry and in outputs.
• Confusing 'validation' and 'verification' is a common misconception.
Remembering the former is usually done by the computer and the latter by
people may help.
• Using the wrong fields and/or criteria when doing searches, sorts or queries.
Pupils need guidance in interpreting questions so that they can construct
sorts, searches and queries correctly.