garmin nuvi updating points of interest - Access validating

Validation rules prevent bad data being saved in your table. You can create a rule for a field (lower pane of table design), or for the table (in the Properties box in table design.) Use the table's rule to compare fields. In some versions of Access, you will not be able to leave the field blank once you add the validation rule, i.e. If you need to be able to leave the field blank, add OR Is Null to your rule.

For instance, suppose you want to ensure that the right data is entered in the Gender field.

This article explains how to use validation rules and validation text in table fields and form controls.

Use this rule to compare values across different fields, or to delay validation until the last moment before the record is saved.

Examples: In designing a database, you walk a tightrope between blocking bad data and accepting anything.

Example 3: Using the Set Field Macro Action The following code example shows a validation rule that resets the status of a line item when its quantity is increased.

object to determine whether the value in the Quantity field was increased.

Protecting the validity of your data is one of the most important tasks of a database developer.

To ensure that users enter accurate data, start at the foundation.

You cannot tab to the next field until you enter something that satisfies the rule, or undo your entry.

Examples: The Yes/No field in Access does not support Null as other databases do.

If the data doesn't satisfy the conditions you've set, Access won't accept the input value.

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