When loading data into an Oracle database using SQL Loader, it is important to handle data errors and reject invalid records effectively. This ensures data integrity and helps maintain the accuracy and reliability of the database.

SQL Loader provides several options to handle data errors and reject invalid records during the data loading process. By utilizing these options, you can identify and handle erroneous data gracefully.

1. Specification of Data Conversion Rules

One of the first steps in handling data errors is specifying the data conversion rules for each field in the input file. This can be done by using the CONVERT or DATE_FORMAT clauses in the control file of SQL Loader. These clauses allow you to define the format and data type for each field, enabling SQL Loader to validate the data during the loading process.

For example, to specify a conversion rule for a numeric field called “age”, you can use the following syntax:

age INTEGER EXTERNAL

This specifies that the “age” field should be converted to an integer data type.

2. Rejecting Invalid Records

SQL Loader allows you to reject records that fail to meet the specified data conversion or validation rules. These rejected records can be written to separate files for further analysis or correction.

To enable the rejection of invalid records, you can use the ERRORS parameter in the SQL Loader control file. This parameter specifies the maximum number of errors allowed before the loading process is terminated.

For example, to reject records with more than 10 errors, you can use the following syntax:

ERRORS 10

By default, rejected records are written to a file with the .bad extension. You can specify a different file name using the DISCARD parameter in the control file.

3. Logging Error Messages

SQL Loader provides logging options to capture detailed error information during the loading process. This helps in identifying the specific errors encountered and their corresponding records.

To enable error logging, you can use the LOG parameter in the control file. This parameter specifies the name of the log file to which error messages should be written.

For example, to log error messages to a file called “load_errors.log”, you can use the following syntax:

LOG load_errors.log

The log file contains information such as the record number, field name, and error message for each rejected record.

Conclusion

Handling data errors and rejecting invalid records in SQL Loader is crucial for maintaining the integrity and accuracy of the loaded data. By specifying data conversion rules, rejecting invalid records, and logging error messages, you can effectively handle data errors and ensure the reliability of your database.

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