PRACTICAL GUIDEUnder review

DBSkip and record navigation

Traverses a bounded sequence with movement and end checks.

DBSkip and record navigationAdvPL

01 · OVERVIEW

Overview

A loop needs a start, end condition and movement. DBGoTop starts at the first logical position; DBSkip follows order and filter, and EOF must be checked before field access. The example visits at most three visible records on owned EDTRB and only counts without exposing data. Filters and deleted-record settings affect the count; it is not the table total. The alias stays at the reached position, possibly EOF. (TOTVS, n.d., refs. 1–2)

03 · PRACTICAL EXAMPLE

Commented example

#Include "Protheus.ch"
User Function Ed341()
    Local nCount := 0
    If Select("EDTRB") > 0
        EDTRB->(DBGoTop())
        While !EDTRB->(Eof()) .And. nCount < 3
            nCount++
            EDTRB->(DBSkip(1))
        EndDo
        ConOut(cValToChar(nCount))
    EndIf
Return Nil

Expected result

Count from zero to three, depending on visible records. Under review: editorial example neither compiled nor run in Protheus. Check includes, release, RDD and context before testing.

BEST PRACTICES

Keep movement inside the loop. Ensure a reading context without pending changes; restore area and position when the caller requires it.
Under review: editorial example neither compiled nor run in Protheus. Check includes, release, RDD and context before testing.

DBSkip and record navigation

Overview

Commented example

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