mirror of
https://github.com/microsoft/BCQuality.git
synced 2026-10-05 22:56:55 +01:00
b6da405376
Lead with a complete plugin quick start and add task-oriented usage, troubleshooting, customization, and contribution guides. Preserve the broader plugin framing, correct conflicting contract guidance, support Agents folder reviews, and align repository validation. Convert existing sample references to clickable links without changing knowledge rules. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
26 lines
1.4 KiB
Markdown
26 lines
1.4 KiB
Markdown
---
|
|
bc-version: [all]
|
|
domain: performance
|
|
keywords: [isempty, count, findfirst, existence-check, exists]
|
|
technologies: [al]
|
|
countries: [w1]
|
|
application-area: [all]
|
|
---
|
|
|
|
# Use IsEmpty for existence checks, not Count() or FindFirst()
|
|
|
|
## Description
|
|
|
|
When the caller only needs to know whether any row matches a filter, `IsEmpty()` is the API designed for the question. Per the upstream guidance, "`IsEmpty()` is more efficient as it stops at first record found." `Count() > 0` materializes a count the caller does not need; `FindFirst()` materializes a row the caller does not need. Both do work that `IsEmpty` does not.
|
|
|
|
## Best Practice
|
|
|
|
Phrase existence checks as `if not Record.IsEmpty() then ...` (or `if Record.IsEmpty() then ...` for the negative). Apply filters via `SetRange`/`SetFilter` before the call so the existence check runs against the intended subset. Reserve `Count` for cases where the actual number matters and `FindFirst` for cases where the record fields are read.
|
|
|
|
See sample: [`use-isempty-for-existence-check.good.al`](use-isempty-for-existence-check.good.al).
|
|
|
|
## Anti Pattern
|
|
|
|
`if Customer.Count() > 0 then ...` and `if Customer.FindFirst() then ...` (when the record is discarded) — both are flagged by the upstream guidance as the wrong tool. The first asks the database for the full count; the second asks for a row's fields. Both answers go unused.
|
|
|
|
See sample: [`use-isempty-for-existence-check.bad.al`](use-isempty-for-existence-check.bad.al).
|