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tryfetch_try_to_get_a_specific_record_by_key_value_.htm
Navigation:  ABC Library Reference > FileManager > FileManager Methods >====== TryFetch (try to get a specific record by key value) C6H0009.jpg ====== Previous pageReturn to chapter overviewNext page

TryFetch( key ), VIRTUAL, PROC

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TryFetch Gets a specific record by its key value.
key The label of the primed KEY.

The TryFetch method gets a specific record by its key value. You must prime the key before calling TryFetch. If the key is not unique, TryFetch gets the first record with the specified key value.

The Fetch method provides a slightly different (automatic) alternative for fetching specific records.

Implementation:

TryFetch tries to get the specified record. If it succeeds, it returns Level:Benign. If it fails, it returns Level:Notify and does not clear the record buffer. See Error Class for more information on Level:Benign and Level:Notify.

Return Data Type:     BYTE

Example:

PROGRAM

INCLUDE('ABFILE.INC')             !declare FileManager class

MAP                               !program map

END

GlobalErrors  ErrorClass           !declare GlobalErrors object

Access:State  CLASS(FileManager)   !declare Access:States object

             END

States       FILE,DRIVER('TOPSPEED'),PRE(ST),CREATE,BINDABLE,THREAD

StateCodeKey KEY(ST:StateCode),NOCASE,OPT,PRIMARY

Record        RECORD,PRE()

StateCode      STRING(2)

State          STRING(20)

             END

            END

 CODE

!program code

!get the state record for Florida

ST:StateCode = 'FL'              !prime the state key for the fetch

IF Access:States.TryFetch(ST:StateCodeKey)!fetch the record

 GlobalErrors.Throw(Msg:FieldNotInFile)  !handle any errors yourself

END

See Also:     Fetch , GET

tryfetch_try_to_get_a_specific_record_by_key_value_.htm.txt · Last modified: 2021/04/15 15:57 by 127.0.0.1