Quick Tip: CalcFields vs SetAutoCalcFields in AL
FlowFields in Business Central are not stored in the database and must be calculated explicitly. The post explains two methods for calculating them: CalcFields for one-time calculations on single records, and SetAutoCalcFields for automatic calculation during record retrieval, with guidance on which to use to avoid performance issues.
post think about IT
"Inside a loop, calling CalcFields on every iteration means a separate database call per record."
Key points
- CalcFields explicitly calculates FlowFields on the current record when called and is suitable for single-record calculations outside loops
- SetAutoCalcFields automatically calculates specified FlowFields for every record retrieved during FindSet or loop iterations, improving performance over repeated CalcFields calls
- Calling SetAutoCalcFields without parameters clears the auto-calculation list for the record variable
- SetAutoCalcFields is scoped to the record variable, not the table, so different variables do not inherit the setting
- As of BC26 (AL runtime 15.0), SetAutoCalcFields is available on RecordRef, enabling generic code to use the same pattern
Quotes
- “Inside a loop, calling CalcFields on every iteration means a separate database call per record.” (Explains the key performance problem that SetAutoCalcFields solves)
- “Use SetAutoCalcFields before any loop where you need a FlowField on every record.” (Provides the main guideline for correct usage to achieve optimal performance)
Context
- Features: CalcFields method, SetAutoCalcFields method, FlowField calculation, RecordRef support
- Versions: BC26, 2025 release wave 1, AL runtime 15.0
Source: think about IT - Steven Renders, community blog. Summary, key points and quotes are derived (CONTENT-NOTICE.md); read the original for the full text.