Michael knows that data validation is a must to have a perfect working environment. The data being entered in the tables has to be correct and valid. Data validation is the process to ensure this.

The two important types of data validation are:

1. Field level validation: Validates the data being entered in an individual field.
2. Record level validation: Validates data from more than one field with reference to one another so as to ensure correct data. For example the Retirement date of an employee cannot be the same as his Joining date, andit must belong to a time period subsequent to the joining date. This requires record level validation.

In This Chapter:

Input Mask

The first type of field level data validation is the input mask.

Validation Rules and Text

Validation Rules validate data when data in a field is added or changed, or when you save a record. Validation Text specifies the text of the message that appears if the field, control, or record does not satisfy the cond

Defaults and Required Values

Now we will show you how to setup default values and specify whether or not values can be left blank.

Lookup Values

This refers to a list of values, which can be specified or can come from another table or query (Lookup list).

Record Validation Rules

Now that Michael is familiar with the field level validation, George moves onto the Record Validation Rules that will allow him to compare values from more than one field.