82 lines
2.5 KiB
Markdown
82 lines
2.5 KiB
Markdown
---
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title: "if not IsEmpty then FindSet"
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tags: ["AL","Performance"]
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categories: ["Best Practice"]
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---
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_Created by SosicStefan, Described by SosicStefan_
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## Introduction
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When retrieving records in Business Central, a common pattern is using `IsEmpty` before calling `FindSet` to check whether data exists. However, this approach is redundant and can lead to unnecessary database queries. Business Central’s runtime already optimizes `FindSet` to avoid unnecessary retrieval operations.
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## Why Not Use 'If Not IsEmpty Then FindSet'?
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The following pattern:
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```al
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if not Customer.IsEmpty() then
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Customer.FindSet();
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```
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This introduces inefficiencies due to:
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- Redundant checks: Business Central internally wraps FindSet in an IF EXISTS query when repeated on platform level itself.
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- Extra queries: Calling IsEmpty separately can lead to duplicate execution of SELECT TOP 1 NULL, slowing down performance.
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## How Business Central Optimizes FindSet
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Consider the following loop:
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```al
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internal procedure IsEmptyAndFindSet()
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var
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Customer: Record Customer;
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i: Integer;
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begin
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for i := 1 to 10 do begin
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Customer.SetRange("Country/Region Code", 'RS');
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if not Customer.IsEmpty() then
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Customer.FindSet();
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end;
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end;
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```
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With this code being executed, Business Central will run two queries on SQL:
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- One for checking `IsEmpty`
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- Second for getting dataset with `FindSet`
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## Best Practice: Use FindSet Directly
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Instead of checking `IsEmpty` first, simply use only `FindSet`:
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```al
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internal procedure FindSetWithoutIsEmpty()
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var
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Customer: Record Customer;
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i: Integer;
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begin
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for i := 1 to 10 do begin
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Customer.SetRange("Country/Region Code", 'RS');
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if Customer.FindSet() then;
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end;
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end;
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```
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Initially, Business Central runs a normal `SELECT` query to retrieve the data.
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However, after running this query for three times, on fourth time the system switches to an optimized query:
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After optimized query, the platform already applies the `IF EXISTS` logic dynamically. Means that explicitly calling `IsEmpty` before `FindSet` is unnecessary.
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Full query execution looks like this:
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## Summary
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Avoid using if not `IsEmpty` then `FindSet`, as Business Central optimizes `FindSet` at the runtime level. This approach eliminates redundant queries, improves performance, and ensures cleaner code.
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