Chapter 3: Database Applications Defintions

Chapter 3: Database Applications Defintions

1. Table

   • A file which is formatted into rows and columns. It is 2D and referred to as a ' Flat File '

2. Field

   • Part of a record which stores a single data item.
   • Record
     • Is represented as a row in a table. Consists of data related a person
     • Key Field (primary key)
       • Used to uniquely identify one record, e.g. customer name, each customer has a unique name

3. Query

   • A way of searching and extracting data from a database to find a answer to a queation
     • Checks each record to find what suits its criteria.

4. Form

   • A common way to collect data.
     • when data is entered, its automatically added to a table as stored in a database.

5. Report

   • Allows tables and results from queries to be preseneted in a user friendly way.

6. Macros

   • A small program written to perform a repetive database task automatically.

7. Database reltionships

   • Links two tables together.
   • Non-key field(Foreign Key)
     • A common field that allows the link between to tables i.e customer Id
   • Referential Integrity
     • Ensures that when a cutomer record is deleted, it deletes there records in all linked tables

8. Data Validation

   • Gurantees that data is present and the correct type, range, length
     • Presence Check
       • Ensures that data is present.
     • Length check
       • Ensures that data is the correct amount of characters
     • Type Check
       • Used to ensure data is the correct type
     • Format check
       • Ensure that data matches a pattern i.e date
     • Range Check
       • Ensures thata data is within a upper and lower limit
     • Logical Operator
       • Compares values againist other data