Topic 3-Database Concepts Flashcards
Table
A table consisting of a number of records
Record
A record is represented as a row in a table
Field
A field is part of a record that stores a single data item,represented by a column
Key field
A key field uniquely identifies one record
Query
A query searches snd filters data in a database that satisfies the query criteria
Forms
Forms are used to collect data to create a new record,modify an existing record or view records already stored in a table
Reports
Reports are used to present results from queries in an efficient manner
The layout of reports can be customised,such sd grouping similar data or presenting data in ascending or descending order
Macros
- Macros are small programs that are written to preform a repetitive database task automatically
- They are used to add functionality to forms and reports
- Running a macro will result in instructions stored within the macro being executed with a single click of a button
Database relationships
- Database relationships link two or more tables in a database using a relationship type
- For this to happen,a common field must be stored in each table;the key field from one table as a non-key field (also called a ‘foreign key’)
- Relationships are defined as one-to-one, one-to-many or many-to-many
Importing data
- It is possible to import a number of worksheets from a spreadsheet to a database package or vice versa
- This gives organisations more flexibility in handling their data
Text
Text and data that is a mixture of text and numbers,e.g. as a postcode
Number
Numeric data that requires a mathematical calculation
Date/Time
Dates and times
Currency
Monetary data;includes 2 decimal places
Autonumber
To create a key field,the computer generates sequential numbers that are automatically inserted for each new record created
Yes/No
Data that has two possible values,e.g. Yes/No or True/False;this is called a ‘Boolean value’
OLE object
Object linking and embedding;objects created using a software package other than a database
Hyperlink
A link to a web address (URL)
Attachment
A file attached to a record,e.g. a digital image
Calculated
The result pf 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
- Data validation involves checking of data at the input stage to ensure it is reasonable,sensible and within acceptable limits
- It guarantees that is present,and of the correct type,range or length
- The computer checks data and either accepts the data,or rejects it and displays an error message
- A number of data validation checks exsist
Presence check
Ensures data is present;the field cannot be left blank
Length check
Ensures data is the correct number of characters
