Automatic data file modification

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Help / WLanguage / Managing databases / HFSQL / Automatic data modification

Overview
When is the automatic data modification required?
Performing the automatic modification of data files
Development computer
Deployment computer
Notes
Running the automatic data file modification several times
Default configuration of setup program
Saving data files
Force automatic modification of data files
Analysis shared between several applications and sites
Access rights to the data file
Limitation

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Automatic data file modification

Available only with these kinds of connection

Overview

The automatic data file modification updates the description of data files on user computers.

If the structure of one or more data files has changed on the development workstation (adding or deleting fields, modifying fields, etc.), these changes must be transferred to the user workstations when the application is updated.

If the application is updated while no automatic data modification is performed, the application found on the end-user computers may:

no longer operate properly.
generate programming errors.

Caution: In the case of a network update with automatic modification of data files, installation of the application update on user workstations must be mandatory.

Remarks:

The automatic data file modification can be performed through programming with HModifyStructure.
The automatic data modification can only be performed by HModifyStructure.

When is the automatic data modification required?

The automatic data modification is required in the following cases:

	Development computer	User computers

1st case: Modifying the structure of HFSQL Classic or Client/Server data files	The application uses HFSQL Classic or Client/Server data files. The structure of the data files was modified (addition or deletion of items, ...).	The application uses HFSQL Classic or Client/Server data files. These modifications must necessarily be carried over when the application is updated. The structure of the data files will thus be identical to that of the development workstation.
2nd case: Migrating data files from Hyper File 5.5 to HFSQL Classic	The application uses HFSQL Classic data files.	The application uses Hyper File 5.5 data files. Data files must be migrated from Hyper File 5.5 to HFSQL Classic when the application is updated. The structure of the data files will thus be identical to that of the development workstation.
3rd case: Modifying the structure of data files in Hyper File 5.5 format	The application uses Hyper File 5.5 data files. The structure of the data files was modified (addition or deletion of items, ...).	The application uses Hyper File 5.5 data files. These modifications must necessarily be carried over when the application is updated. The structure of the data files will thus be identical to that of the development workstation.

Remark: In the case of a network installation, automatic data modification modifies both the data files on the server workstation and those on the user workstations.

The automatic data modification is required if the structure of the data files was modified from the development computer (addition or deletion of items, ...). These modifications must necessarily be carried over when the application is updated on the user computers (CAB format). The structure of the data files will thus be identical to that of the development workstation.

The automatic data modification is required if the structure of the data files was modified from the development computer (addition or deletion of items, ...). These modifications must necessarily be carried over when the application is updated on the user computers. The structure of the data files will thus be identical to that of the development workstation.

Performing the automatic modification of data files

Development computer

The automatic data file modification is systematically performed when the analysis is generated on the development computer.

To apply the automatic modification to the data files on the end-user computers, the automatic modification must be performed when installing the update of the application or site. The setting of this automatic modification can be done:

by the setup program creation wizard.
in the setup editor (WDInst).
using HModifyStructure in the initialization code of the project, for example.

Note: If required, automatic modification of data files can also be performed when synchronizing data via universal replication or assisted replication.

Deployment computer

When installing an update, the user will be able to configure the automatic modification by clicking the "Advanced" button. This button appears in the first window of the setup program. The following window is displayed:

This window allows you to:

create a report of the operations performed by the automatic data modification. If a problem occurs, this file can be given to the application manager.
By default, this file is named "LOGMODAUTO.TXT" and it is created in the installation directory of the application.
list the HFSQL data files on which the automatic modification will be performed. You will have the ability to add to this list:
- additional data files.
- additional directories containing data files.
specify additional directories containing data files in Hyper File 5.5 format that are not automatically found during the update.

Remarks:

During the update, the data files automatically found are:
- data files in the application installation directory.
- data files listed in the ".REP" file. For more details, see the help about the management of .REP files.
To prevent the user from accessing the options used to configure the automatic modification, the setup editor WDInst allows you to make the "Advanced" button invisible in the setup program.

iPhone and iPad
HModifyStructure is used to perform an automatic modification of the data files installed on iPhone or iPad. We advise you to call this function in the project initialization code.

Notes

Running the automatic data file modification several times

The automatic modification will have no effect on the application if it is performed on data that is already updated.

Default configuration of setup program

If the application is associated with an analysis, the setup program proposes to perform the automatic modification of the data files. The user can access the options used to configure the automatic modification by clicking the "Advanced" button.

Saving data files

The data files of the application are automatically backed up before the automatic modification is performed. The backup directories are named:

"Auto Modif Save (<DateModifAuto> <HeureModifAuto>)" for automated modification of data files in Hyper File 5.5 or HFSQL Classic format.
"Files before conversion (<DateAutoModif> <TimeAutoModif>)" for migrating data files from Hyper File 5.5 to HFSQL Classic.

Force automatic modification of data files

The automatic modification of the data files can be performed at any time on the development computer.

In some cases, automatic data modification may not be carried out correctly: data files present on a laptop not connected to the network at the time of update, faulty update, etc. In such cases, it is necessary to force automatic data modification in order to use the application.. To do so, WDModFic must be used. For more details on this tool, see WDModFic: Tool for automatic modification of data files.

Analysis shared between several applications and sites

For an analysis shared between several applications or sites, after the automatic modification of data files, all the executables and sites that share the analysis must be updated. However, it is possible to authorize an application or site to use a more recent data file description, using the HCheckStructure function.

"Live" modification of data files
The modification of the data files can be performed even if applications are accessing these data files.
During the modification of the data files, the different applications that handle the data files continue to operate.

The application will no longer operate if the modifications are not compatible (deleting a key, deleting a unique key, deleting identifiers, deleting data files or items, modifying the format of an item, ...)

During the first access to a data file whose structure is not compatible, an error indicates that the structure of the data file differs from the structure of the analysis.
In the case of adding fields, adding keys, adding data files, the application will continue to function normally (unless the HCheckStructure function has been used with the constant hIdentique).

Access rights to the data file

The modification of the data files provokes the recreation of the data file on disk. In an allocation system that manages rights at file level (NTFS...), the data file after automatic modification will therefore have the rights of the directory to which it belongs.

Before the automatic modification, if the data file had specific rights different from the rights of the folder, they must be redefined in Windows after the modification.

Limitation

The automatic data file modification operates for the data files with indexes only.

Reminder: it is possible to create data files without an Index field.