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skr.11skr.11 

what is system validation and custom validation in Salesforce, Explain the difference between them ? Thanks !

Ishwar ShindeIshwar Shinde
Hello,

System validations are the validation which are enforced by Salesforce like number field should not contians alphabets, phone number should be in valid format etc..

While custom validation rule are the one which are created manually under object.

There is a difference in order of execution for stand and custom validation. Standard validations are run before the before trigger event after that custom validation are executed.

Please mark this as best ans if this helps!!!
SandhyaSandhya (Salesforce Developers) 
Hi ,

The ones provided by Salesforce are a system or standard validation rules - like data type validation for all the fields (email validation for email fields and similar for currency, number type fields, etc.); universally required; unique fields.

All the validations we build ( using validation rules/ VF page ) are the custom validations.

Please refer below links for more information.

https://help.salesforce.com/apex/HTViewHelpDoc?id=fields_about_field_validation.htm&language=en

https://help.salesforce.com/apex/HTViewHelpDoc?id=fields_defining_field_validation_rules.htm&language=en

https://help.salesforce.com/apex/HTViewHelpDoc?id=fields_validation_considerations.htm&language=en

Please let us know if this helps you!

Thanks and Regards
Sandhya
Vasani ParthVasani Parth
Standard Validation

1) We can make field required on layout.
2) We can make field unique on layout for insertion.  etc

Custim Validation

We can create our own validation to stop user inserting bad data on particular fields.

Details

Validation Rule Details : 
https://help.salesforce.com/apex/HTViewHelpDoc?id=fields_about_field_validation.htm&language=en

Validation Rule Defining:
https://help.salesforce.com/apex/HTViewHelpDoc?id=fields_defining_field_validation_rules.htm&language=en

Validation Rule Considerations:
https://help.salesforce.com/apex/HTViewHelpDoc?id=fields_validation_considerations.htm&language=en
Rakesh51Rakesh51
Anything you built within the applications is taken as custom. Anything that comes with the application by default is taken as standard.

For example, Lead Email address it already comes with standard validation rule to make sure that user will enter data in  form of an  email. 

So, if you use your developer  in order to built a validation rule this will be a custom validation rule. ex.: Validations rules, Apex triger validation