To ensure that Capital Shareholder register number is unique, execute one of the following queries according to your database type: Access database: Select [CompanyId], [PersonId], [ShareCompanyId], [SharePersonId], Val([RegisterNumber]) from [CapitalShareHolder] Group by [CompanyId], [PersonId], [ShareCompanyId], [SharePersonId], Val([RegisterNumber]) Having count(*) > 1 SQL Server database: Select [DBId], [CompanyId], [PersonId], [ShareCompanyId], [SharePersonId], Val([RegisterNumber]) from [CapitalShareHolder] Group by [DBId], … Continue reading Ensure that Capital Shareholder register number is unique