Automatic modification of data files

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Automatic modification of data files

Overview

When is the automatic data modification required?

Performing the automatic modification of data files

Notes

See also

Automatic modification of data files

Available only with these kinds of connection

Overview

The automatic modification of data files is used to update the description of data files found on the user computers.

Indeed, if the structure of one or more files has evolved on the development computer (addition, deletion or modification of items), these modifications must necessarily be carried over to the end-user computers 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: For a network update with automatic modification of data files, the application update must necessarily be installed on the user computers.

Remarks:

The automatic modification of data files can be performed through programming with 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. Therefore, the structure of the files will be identical to the one of the development computer.
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. The files must necessarily be migrated from Hyper File 5.5 to HFSQL Classic during the application update. Therefore, the structure of the files will be identical to the one of the development computer.
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. Therefore, the structure of the files will be identical to the one of the development computer.

Remark: For a network setup, the automatic data modification modifies both the data files found on the server and the data files found on the user computers.

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). Therefore, the structure of the files will be identical to the one of the development computer.

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. Therefore, the structure of the files will be identical to the one of the development computer.

Performing the automatic modification of data files

Development computer

The automatic modification of data files 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.

Remark: If necessary, the automatic modification of data files can also be applied during data synchronization via universal replication or assisted replication.

Deployment computer

When installing an update with automatic modification of the data files, the user will be able to configure the automatic modification by clicking the "Advanced" button. This button is found on the first plane of setup program. The following window appears:

This window is used to:

create a report file for 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 setup directory of the application.
list the data files in HFSQL format onto 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:
- the files found in the setup directory of the application.
- the 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 modification of data files 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:

"Backup of Auto Modif (<DateAutoModif> <TimeAutoModif>)" for an automatic 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.

Forcing the automatic modification of files

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

Indeed, in some cases, the automatic data modification cannot be performed properly: data files found on a laptop computer not connected to the network when the update is performed, faulty update, ... In this case, you must force the automatic data modification to be able 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, an application or a site can be allowed to use a more recent file description via HCheckStructure.

"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.
When adding an item, a key or a file, the application will continue to operate as usual (except if HCheckStructure was called with the hIdentical constant).

Access rights to the data file

The modification of the data files provokes the re-creation of the data file on disk. In an allocation system managing the rights at file level (NTFS, ...), the data file after modification will 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 modification of data files operates for the data files with indexes only.

Reminder: You have the ability to create data files containing no Index item.