How To Fix DT978 - Table &: Key too wide for DB & (width: &, maximum width: &)

SAP Error Message - Details

• Message type: E = Error

• Message class: DT - Table activation (incl. indexes)

• Message number: 978

• Message text: Table &: Key too wide for DB & (width: &, maximum width: &)

Self-Explanatory Message

Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of messages in the SAP system have a message text, however this is frequently insufficient to comprehend or resolve the problem.

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Smart SAP Assistant

• What is the cause and solution for SAP error message DT978 - Table &: Key too wide for DB & (width: &, maximum width: &) ?

  The SAP error message DT978 indicates that a key in a database table is too wide for the database system to handle. This typically occurs when the combined length of the fields that make up the primary key exceeds the maximum allowed width for keys in the database.
  Cause:
  
  Key Length Exceeds Limit: The primary key of the table is defined with a total length that exceeds the maximum allowed length for keys in the underlying database. Different databases have different limits on the maximum size of a key.
  Data Type Issues: The data types used in the key may have larger sizes than expected, especially if you are using character types (e.g., CHAR, VARCHAR) with large lengths.
  Table Design: The design of the table may not be optimal, leading to unnecessarily wide keys.
  
  Solution:
  
  Review Key Definition: Check the definition of the primary key in the table. You may need to reduce the number of fields in the key or change the data types to smaller sizes.
  Optimize Key Fields: If possible, consider using fewer fields in the primary key or using surrogate keys (like an auto-incrementing integer) instead of composite keys.
  Database Configuration: If you are using a specific database (like Oracle, SQL Server, etc.), check the documentation for the maximum key length and ensure your key complies with those limits.
  Table Redesign: If the table design is not optimal, consider redesigning the table to better fit the requirements and constraints of the database.
  Consult SAP Notes: Check for any relevant SAP Notes or documentation that may provide additional guidance or solutions specific to your version of SAP.
  
  Related Information:
  
  Database Limits: Different databases have different limits for key sizes. For example, in Oracle, the maximum size for a primary key is typically 1000 bytes, while in SQL Server, it can be up to 900 bytes.
  SAP Version: The behavior and limits may vary depending on the version of SAP you are using, so ensure you are referencing the correct documentation for your version.
  Performance Considerations: Wide keys can also lead to performance issues, as they may increase the size of indexes and slow down query performance.
  
  If you continue to experience issues after attempting these solutions, it may be beneficial to consult with your SAP Basis team or a database administrator for further assistance.