<Source>.Last (Function)

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Read operation based on a key
Password verification
Miscellaneous
Comparing .ReadLast and <Source>.Last
Locks

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<Source>.Last (Function)

In french: <Source>.Dernier

Not available with this kind of connection

Sets the position on the last record of a data file according to a browse item. The record is not read.
The number of the current record is modified only when it is returned by <Source>.RecNum. For functions handling the current record number by default (functions <Source>.Delete, <Source>.Read, <Source>.Modify, ...), the value of this number is not updated: you must use the <Source>.RecNum() function. For example: do not:

Client.Supprime()

but

Client.Supprime(Client.NumEnr())

The highest value in the browse item is read (for more details, see remarks).

Warning The record loaded into memory is not modified. HFSQL variables (e. g. Customer.Name, or the Name item of the Customer data file) are not updated.

In most cases, <Source>.Last is used to set the position in the data file in order to perform a read loop with <Source>.Previous.

Several cases may occur after the call to <Source>.Last:

the data file is empty or there is no record corresponding to the filter (defined by <Source>.Filter): function <Source>.Out returns True.
the function attempts to block a record already blocked in play mode: function HErrorLock returns True and function <Source>.Out returns True.
JDBC access: lock management is not supported for databases that are accessed through JDBC.
Management of locks not available in SQLite databases.

Example

// Parcours d'un fichier de données depuis le dernier enregistrement
Client.Dernier(Nom)
WHILE NOT Client.EnDehors()
	// Traitement de l'enregistrement
	Client.Précédent(Nom)
END

Syntax

<Result> = <Source>.Last([<Search key item> [, <Options>]])

<Result>: Boolean

True if the position was set,
False if an error occurs. This problem can be caused by:
or a positioning problem (empty data file, etc.): function <Source>.Found returns False and function HError returns 0.
an error: HError returns an integer other than 0. HErrorInfo returns more details.

<Source>: Type corresponding to the specified source

Name of the data file used.

<Search key item>: Optional character string

Name of the key item used to loop through the data file. If this name is not specified, <Source>.Last will use the last browse item used on this data file by the last HFSQL management function (function starting with "H"). If this item does not exist, the best browse item is automatically used.

<Options>: Optional constant

Configures the lock set on the record selected by <Source>.Last:
hKeepFilter The filter set by <Source>.Filter will be taken into account, even if the search key is not optimized for the filter. Reminder: <Source>.Filter returns the optimized search key for the filter.
Caution: in this case, on large data files, performance problems may occur..
This constant cannot be used.
hLockNo No blocking: the Record can be played back or modified by another application.
hLockReadWrite Lock in read/write mode: the selected record cannot be read or modified by another application.
hLockWrite Lock in write mode: the selected record can be read by another application, but cannot be modified by another application.
JDBC access: This constant is not available.
hNoRefresh
The table or query content will not be refreshed. All the saved positions are stored.
If this parameter is not specified, function <Source>.Last resets the browse for the specified item: the contents of the table or query are refreshed with data from the OLE DB database.. All the saved positions are lost. The position will be restored according to the value of best item.
Note: Routes and positions saved on other browse items are never assigned.

The lock options will have no effect if the locks are not supported by the OLE DB provider or by the Native Connector.
The lock options are ignored. Use the lock functions (<Source>.LockRecNum) kept for backward compatibility.
JDBC access: lock management is not supported for databases that are accessed through JDBC.
Management of locks not available in SQLite databases.

Remarks

Read operation based on a key

<Source>.Last sets the position on the record with the greatest key value.

The sort order taken into account is the one specified in the analysis for this key.

If duplicates are found, <Source>.Last sets the position on the first "duplicate" record according to the sequence of record numbers.

Password verification

If <Source>.Last is the first function that handles the specified data file, the password is checked when opening the data file.

If the password is incorrect, HErrorPassword returns True and <Source>.Out returns True.

Miscellaneous

<Source>.RecNum returns the current record number.
<Source>.ChangeKey changes the search key while keeping the position on the current record.

Comparing <Source>.ReadLast and <Source>.Last

The function <Source>.Last function does not play the Record: the <Source>.Last is therefore faster than function <Source>.ReadLast.

Locks

By default (<Options> not specified), the record is not locked.

If a lock is requested (hLockWrite or hLockReadWrite constant), the position will be set on the record only if it is not already locked.

Component: wd300hf.dll