Understanding SSIS 816: A Comprehensive Guide


Mar 25, 2024
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SQL Server Integration Services ssis 816 is a powerful tool within the SQL Server ecosystem designed to automate data extraction, transformation, and loading (ETL) processes. SSIS packages, consisting of interconnected tasks, provide a visual and code-based approach to managing data flows across diverse sources and destinations.

One specific error code you might encounter during SSIS package execution is SSIS 816. This error signifies an issue related to data type incompatibility between the data being processed and the target destination column. Let’s delve deeper into understanding the causes, mitigation strategies, and best practices to effectively address SSIS 816.

What is SSIS 816?

The SSIS 816 error, formally known as “The conversion failed because the destination column has a data type that is incompatible with the source data type.”, occurs when SSIS attempts to transfer data from a source into a destination column but encounters a data type mismatch. This incompatibility prevents the data from being loaded successfully.

Common Causes of SSIS 816

Here are the primary reasons why you might encounter the SSIS 816 error:

  • Mismatched Data Types: The source data type (e.g., integer, string, date) doesn’t align with the data type defined for the destination column in the target table. For instance, attempting to insert a string value into a numeric column will trigger this error.
  • Implicit Conversion Issues: SSIS might try to implicitly convert data types during the transfer process. However, if the conversion is not feasible because of significant data type differences (e.g., string to date), the SSIS 816 error will arise.
  • Null Values and Data Length: If the source data contains null values and the destination column doesn’t allow nulls, or if the source data exceeds the defined length of the target column, this error can surface.

Identifying the SSIS 816 Error

The SSIS 816 error manifests in a few ways:

  • Error Message: During package execution, the SSIS Error List will display a message similar to “The conversion failed because the destination column [Column Name] has a data type that is incompatible with the source data type.”
  • Task Failure: The specific task responsible for data transfer (e.g., Data Flow task) will fail and mark the package execution as unsuccessful.
  • Event Viewer Logs: The Windows Event Viewer might contain entries related to the SSIS 816 error, providing additional context for troubleshooting.

Resolving SSIS 816: Proven Strategies

To effectively address the SSIS 816 error, follow these steps:

  1. Examine source and destination data types:
    • Open the SSIS package and access the Data Flow task.
    • Identify the source and destination components involved in the data transfer operation.
    • Right-click on the source component and select “Edit.”.
    • Review the “Output Columns” section to understand the source data types.
    • In the destination table, inspect the data types defined for the target columns.
    • Compare these data types to pinpoint where the mismatch occurs.
  2. Modify the data flow:
    • There are two primary approaches to rectifying the data type incompatibility:
      • Modify Source Data: If feasible, modify the data extraction logic at the source to transform the data into a format compatible with the destination column. You can achieve this using data transformation tasks within the SSIS package (e.g., the Data Conversion task).
      • Alter Destination Column: If modifying the source data is not possible or desirable, alter the data type of the target column in the destination table to accommodate the source data type. However, ensure this change aligns with the overall data integrity of your database schema.
  1. Utilize the Data Conversion Task:
    • If you opt to modify the data within the SSIS package, leverage the Data Conversion task.
    • Configure the Data Conversion task to transform the source data into the necessary data type for the destination column. SSIS offers various data conversion options to cater to different data types and scenarios.
  2. Handle null values:
    • If the source data might contain null values, configure the destination component to handle them appropriately. You can either modify the destination column to allow nulls or create a default value (e.g., 0 for numeric columns) to be inserted in case of nulls.
  3. Truncate Data:
    • If the source data exceeds the length defined for the destination column.

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