Sql validating data against data type
Expressions can also perform mathematical operations. For example, the expression You can add a field validation rule and/or a record validation rule.A field validation rule checks input to a field, and is applied when the focus leaves the field.When data is entered, Access checks to see whether the input breaks a validation rule – if so, the input is not accepted, and Access displays a message.Access provides a number of ways to restrict input: You can use these methods of validating data alone or in combination with each other.Data validation ensures that the data complies with the requirements and quality benchmarks. Data validation primarily helps in ensuring that the data sent to connected applications is complete, accurate, secure and consistent.This is achieved through data validation's checks and rules that routinely check for the validity of data.Data types are not optional, and provide the most basic type of data validation.For more information about data types, field sizes, and input masks, see the article Introduction to data types and field properties.
Validation rules can be set in either table design or table datasheet view.Typically, you use a form validation rule instead of a field validation rule if the rule was specific only to that form and not to the table no matter where it was used.This article explains how to use validation rules and validation text in table fields and form controls.A record validation rule checks input to one or more fields is applied when the focus leaves the record.Usually, a record validation rule compares the values of two or more fields.