bcquality/microsoft/knowledge/performance/apply-guards-before-get.md

bc-version	domain	keywords	technologies	countries	application-area
all	performance	get guard early-exit conditional lookup wasted-query	al	w1	all

Apply early-exit guards before calling Get

Description

A Get (or any other database call) executed before a guard that may exit the procedure does a round-trip the procedure never uses. Per the upstream guidance, "Flag Get() calls that execute before a guard condition that may exit early — the DB lookup is wasted." The fix is structural: order the procedure body so cheap checks (parameter validation, in-memory field comparisons, enum tests) run first, and the database call runs only after the guards pass.

Best Practice

Read the procedure top-to-bottom and place every condition that can short-circuit ahead of every database call. The check if SomeNo = '' then exit; belongs above Header.Get(...), not below. Each guard moved upward saves one wasted query on the path that exits.

See sample: apply-guards-before-get.good.al.

Anti Pattern

Record.Get(...) at the top of a procedure followed by if SomeField = '' then exit;. The code reads top-down as "load the record, then decide whether we needed it" — exactly the order that wastes the query. The pattern is easy to introduce when guards are added later, defensively, without re-checking call ordering.

See sample: apply-guards-before-get.bad.al.