How do you enforce data integrity when importing a large CSV file into Salesforce containing records across multiple related objects, ensuring no duplicate records are created?

Enforcing data integrity and preventing duplicate records when importing a large CSV file into Salesforce that involves multiple related objects requires a comprehensive approach encompassing data preparation, careful configuration of the import process, and leveraging Salesforce’s built-in tools and functionalities. First and foremost, before even attempting the import, meticulous data preparation is critical. This means reviewing the CSV file to identify potential inconsistencies, errors, and duplicates. Standardizing data formats (like dates, phone numbers, and addresses) and cleaning inconsistencies will lead to cleaner and more accurate data within Salesforce. Next, determine how the related objects will be connected and make sure the CSV file is structured accordingly. For example, if you're importing accounts and contacts, you'd need an external ID on the account object that can be referenced by the contact import file to associate contacts with specific accounts. The use of external IDs as unique record identifiers is fundamental. Instead of relying on Salesforce IDs, which will not be available until the records are created, external IDs from the originating system (or a custom unique identifier) should be included in the CSV. These IDs should be included both on the parent object (e.g., Account) and child object (e.g., Contact), so they can be matched upon import.

The next phase focuses on configuring the import process. Salesforce’s data import wizard and DataLoader tool can both perform imports. When using either of these tools, take advantage of the available matching rules and duplicate rules. The data import wizard allows you to map the CSV columns to the appropriate fields in Salesforce and helps in configuring matching criteria. For instance, when importing contacts, a matching rule can be configured based on fields like email address or a combination of first and last name plus the account name. Make sure matching rules are configured for each object in the import process. DataLoader also offers similar functionalities but with greater customization capabilities, suitable for large volume imports. Within the import wizard or DataLoader, choose "Upsert" instead of "Insert". Upsert allows you to either insert a new record if it doesn't exist based on a specified match criteria, or update an existing record if a match is found. This is the most effective method to prevent duplicates during an import. Furthermore, consider implementing validation rules on the Salesforce objects. Validation rules can help enforce data formats, required fields, and uniqueness before records are created or updated, thereby ensuring data integrity on the Salesforce side. In situations where more complex duplicate detection is necessary, consider creating custom Apex triggers to implement further logic or using third-party duplicate management tools available on AppExchange.

When dealing with multiple related objects, it's advisable to import in a specific order. Import the parent object first (e.g., Accounts), and then import the child object (e.g., Contacts), using the external ID to establish the relationship. This sequence avoids issues with orphan records. After each import step, carefully review the import log files provided by Salesforce. These files will highlight errors, skipped records, or duplicate records that were skipped, and provide a valuable feedback mechanism. This will allow the administrator to make the necessary changes for the next import. For example, if records are being rejected due to a validation error, it will show the record and the field that was not validated properly. When doing large volume data imports that require integration with other Salesforce tools, Apex batch jobs should be considered to ensure that data import operations do not exceed governor limits and that the operation can be done in a controlled and stable manner.