* Validation rules in Salesforce consist of a formula or expressions that evaluate the data in one or more fields in a record to meet the standards you specify before the user can save the record. It returns a “True” or “False” value based on the evaluation of the data. Validation rules are responsible for displaying an error message to the user when the condition is “True” due to an invalid value.
* Validation rules are helpful in enforcing integrity constraints against the data. Here we give conditions in the formula editor. If one validation rule fails, Salesforce proceeds to check another validation rule held within the field or record and shows an appropriate error message at that particular field or above the record.
* You are allowed to create validation rules for fields, objects, campaign members, or case milestones. For example, we can create a validation rule that fires when a user tries to save an account with the incorrect length for the account number.
