How to Update Fields that Contain Data

When using the Schema Change Wizard, you may encounter errors when you alter fields containing data, since the existing data may not obey your new data entry constraints. For example, if you alter a field to no longer allow NULL values and your existing data contains NULL values for that field (and that field does not have a default value), the program will issue an integrity constraint error.

Likewise, if you change the data type or size of a key field, your existing data may not have unique keys for each record. In this case, you may need to use a temporary field to hold your existing data while you resolve the uniqueness issue.

Another example of an error you could encounter is changes in validation constraints. If you make a field of data validate against another table, your existing data values may not all exist in that table.

To identify these errors:

1. Consult the log file to find which records have the data errors.
2. Edit the reference database to resolve the issues with the data if copying data, or edit the schema of the destination database to resolve the issue with the constraint.
3. Rerun the wizard.