HVersion (Function)

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Incrementing the version number of the data file
Multi-file queries

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HVersion (Function)

In french: HVersion

Not available with this kind of connection

Allows you to find out:

whether the content of a data file was modified.
whether the content of a data file used by a query was modified.

This function is used to detect the modifications made to a data file shared among several programs. If a modification is detected, you have the ability to refresh the data displayed in the window or in the page.

Example

VerNum = HVersion(Customer)

// First evaluation of the data file version
VerNum is int
VerNum = HVersion(Customer)
// Processes
// Second evaluation of the data file version
IF VerNum <> HVersion(Customer) THEN
Info("The Customer data file was modified.")
END

Syntax

<Result> = HVersion([<Data file or query>])

<Result>: Integer

Version number of the data file.
The version number is always equal to 0.

<Data file or query>: Optional character string

Name of the data file used.
Name of the query used.
If this parameter is not specified, HVersion will handle the last data file (last query) used.
The data file used must be an HFSQL data file. Otherwise, the version number is always equal to 0.

Remarks

Incrementing the version number of the data file

When creating the data file, the version number is initialized to 1. This number is incremented whenever the file content is modified (HAdd, HWrite, HModify, TableSave, TableDelete, HFree, HDelete, HCross). The number is incremented if the function is successful.

Remark: HVersion can be used on indexed or non-indexed data files.

Multi-file queries

In the case of a multi-file query, HVersion returns the sum of the HVersion of all data files used in the query.

Component: wd290hf.dll