Assignment, Variables, Constants & Sequences
Inputs, Outputs & Type Conversion
IF Statements & Boolean Operators
Nested Selection and Iteration
WHILE, REPEAT-UNTIL Loops
Validation and verification
Validation and authentication routines
High-level & Low-level languages
Assemblers, Compilers & Interpreters
Database validation is a process where the data entered in the database is checked to make sure that it is correct. The purpose of validation is to make sure that data is logical, rational, complete and within acceptable limits.
There are a range of validation methods like range check, type check etc. (see table in notes for more details)
A range check is probably the simplest validation method to understand. We give the user a range of values that are valid to enter then check they have entered a value in that range.
For example we could ask the user to enter a number between 1 and 10. Our validation routine would then check if the value entered was in that range. If the user entered say the number 11 our code should declare the value 'invalid' and ask the user to enter another value
A range check lets you set appropriate limits:
I have coded the simple example above using a function called data validation. Run the code and check that it works.