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Glossary
of Terms
- Boolean
type
- A
data type used to hold the value True or False.
- Character
type
- A
data type used to hold a single character.
- Condition
- An
expression which can be evaluated as being either True or False.
eg. date of birth < 01/01/90
- Database
- A
collection of data records organised in an easily stored and
accessible way.
- Data
type
- A
definition that states the kind of data that can be entered
into a data field.
eg. real, integer, text, date.
- Data
validation
- The
process of ensuring, as far as possible, that information is
correct by checking it against specific rules and other data,
performed during input and editing of forms.
eg. for a day of month an integer between 1 and 31, or for a
sex field only accepting male or female.
- Field
- A
space on the screen or in a record where data can be entered
or stored.
- File
- A
collection of related records.
- Flat-file
- A
term used to describe a category of databases that will only
allow the user to work with one file at a time - ie. it is impossible
to create a data link between more than one file using a flat-file
database.
- Form
- Analogous
to a paper form used in an office, a database form is a screen
containing blank space called fields into which data items are
entered before being saved as a record in memory.
eg. Surname, Forenames, Sex, Age etc.
- Index
- A
set of 'pointers' stored in a file that allows fast access to
individual records as well as the ability to access records
in a specific order.
- Integer
- A
whole number.
eg. 1, 5000, -27
- Key
- A
data value upon which an index is based.
eg. an employees reference number key will let you find individual
employee details quickly and produce reports in employee reference
number order.
- Operator
- Used
in searches to set the conditions upon which the database is
interrogated.
eg. = < >
- Query
-
The specification of search criteria that are used to interrogate
a database.
- Record
- A
unit of related data items in a file expressed in named data
fields.
- Record
view
- A
display of one record at a time from a database file.
- Relational
- The
combining of data from two or more data files normally achieved
by the linking of common key-values, for example customer details
with customer orders linked via a common account-number field.
eg. stock file, supplier file.
- Report
- A
view of the data contained within the database with suitable
headings and groupings and possibly summary information.
- Search
criteria
- The
conditions upon which a database is interrogated.
eg. sex = "female" AND age <20
- String
- A
data type used to hold a collection of characters.
eg. ant, bee, cow.
- Subset
- A
grouping within a larger group.
- Table
view
- A
display of a collection of records each with the same set of
fields (but different data), arranged in columns for each field.
 Contents:
Databases
Skill
Check: Databases
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