Database Applications Flashcards
a table
consists of a number of records
a field
part of a record that stores a single data item, represented by a column.
a key field
uniquely identifies one record
a query
searches and filter data in a database that satisfies the query criteria
forms
used to collect data to create a new record, modify an existing record or view records already stored in a table.
reports
used to present results from queries in an effective matter. the layout can be customised, such as grouping similar data or presenting data in ascending or descending order.
macros
small programs that are written to perform a repetitive database task automatically. They can be used to add functionality to forms and reports
database relationships
link two or more tables in a database using a relationship type. These are one-to-one, one-to-many or many-to-many.
data type
defines the type of data associated with the field
A database
A structured, organised collection of data that is normally organised into tables of rows and columns.
Flat file database
Only contains one table where data is repeated. Disadvantages- redundancy; when data is repeated unnecessarily. Integrity; data is less likely to be correct because is has been repeated unnecessarily.
Text
Text and data that is a mixture of text and numbers
Number
Numeric data that requires a mathematical calculation
Date/time
Dates and times
Currency
Monetary data; includes two decimal places
Auto number
To create a key field, the computer generated sequential numbers that are automatically inserted for each new record created
Yes/no (Boolean)
Data that has two possible values
OLE object
Object linking and and embedding; objects created using a software package other than a database
Hyperlink
A link to web address (URL)
Attachment
A file attached to a record
Calculated
The result of a calculation produced from another field in the record
Lookup wizard
A value can be selected from a predefined list and entered into the field
Data validation
Involves automatic checking of data at the input stage to ensure it is reasonable, sensible and within acceptable limits. It guarantees that data is present, and of the correct type, range or length
What are the data validation types
Presence check, length check, type check, format check and range check
Presence check
Ensures the data is present; the field cannot be left blank
Length check
Ensures data is the correct number of characters
Type check
Ensures data is of the correct type
Format check
Ensures data matches a predetermined pattern
Range check
Ensures data is within a lower and upper limit
Logical operators
Denoted by the words AND,OR and BETWEEN
Big data
Can be described as the 3vs; volume, variety and velocity
Volume
Refers to the amount of data stored by organisations. Organisations now store large amounts of data from different sources; requiring large storage capacity hardware.
Variety
Refers to the different types and varieties of data. Data is now stored in many formats. Data can be structured, semi-structured or unstructured.
Velocity
Refers to the speed at which data can be processed. Due to large volumes of data, there us a need to use more powerful computers to process the data more quickly
Data analytics
Involves analysing large volumes of data to produce useful information. This is beneficial for making decisions and planning for future growth.
Input mask
Defines the format of the data being entered.
Advantages of linking tables in a database
Reduces Redundancy or repeated information; Increases Integrity
What would you use to display information on a database
A report
