access what is a validation rule
Validation rule. A Validation rule is a criterion or constraint used in the process of data validation, carried out after the data has been encoded onto an input medium and involves a data vet or validation program. This article needs attention from an expert on the subject. A Validation rule is a criterion or constraint used in the process of data validation, carried out after the data has been encoded onto an input medium and involves a data vet or validation program. By using validation rules, you can ensure accurate data entry (to a point). Validation rules catch errors at the data entry level, so in effect, the mistakes never make it into your database. If the data doesn't satisfy the conditions you've set, Access won't accept the input value. VALIDATION RULE EXAMPLES. The following table provides examples of field-level and record-level validation rules, plus. explanatory validation text. You can adapt these examples to fit your content. VALIDATION RULE VALIDATION TEXT. <>0 Enter a nonzero value. >=0 Value must be zero or greater. -or-. Use Access validation rules to ensure accurate data entry. Your Access database is only as sound as the data it stores. Data types can only do so much. The next step is to constrain input values using validation rules. Protecting the validity of your data is one of the most important tasks of a database developer. This article explains how to use validation rules and validation text in table fields and form controls. A validation rule is one way to restrict input in a table field or a control (such as a text box) on a form. Validation text lets you provide a message to help users who input data that is not valid. Right-click the table (in Design view) and select Properties. In the Validation Rule property, enter the expression ([overtime]=0) Or ([hours]=40). Save the table. This rule will accept a value other than 0 in the Overtime field only when the Hours value equals 40. Input validation rules are rules that restrict what values can be entered into a database field. You could, for example create an input validation rule that makes sure a number falls between 1 and 1000. Or you could create an input validation rule that checks if a valid e-mail address was entered. This tutorial will show you how to create your own input validation rules in Access. I will show you validation rule examples for validatinn text, numbers and dates. There are three types of validation rules in Access: 1  Field Validation Rule You can use a validation rule to specify a criterion that all valid field values must meet. 2  Record Validation Rule You can use a validation rule to specify a condition that all valid records must satisfy. Defining a Table Validation Rule. The last detail to define is any validation rules that you want Access 2010 to apply to any fields in the table. Although field validation rules get checked as you enter each new value, Access checks a table validation rule only when you save or add a row. Table validation rules are handy when the values in one field depend on what's stored in another field.
A criterion or constraint used in the process of data validation, carried out after the data has been encoded onto an input medium and involves a data vet or validation program.