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Help / WLanguage / Managing databases / HFSQL / Types of HFSQL variables
  • Properties specific to the description of data files
  • How to describe data files programmatically?
  • Handling the items of a data file described programmatically
  • LogMethod
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Stored procedures
The File Description variable is used to programmatically describe data files. The description of each data file is validated by HDescribeFile.
After this validation:
  • This data file can be handled like any other data file described in the analysis.
  • The "File Description" variable is reinitialized and can be used to describe another data file.
Example
UnFichier is File Description
MonFichier1, MonFichier2 are File Descriptions
// Description du fichier de données "CLIENT"
UnFichier is File Description

UnFichier.Nom = "CLIENT"
UnFichier.Type = hFileNormal
UnFichier.CryptageFic = hEncryptionStandard

// Description des rubriques du fichier de données
...

// Validation de la description du fichier de données "CLIENT"
HDescribeFile(UnFichier)
Syntax

Declaring one or more descriptions of data files Hide the details

<Variable name> is File Description
<Variable name 1>, <Variable name 2> are File Descriptions
<Variable name>:
Name of the "File Description" variable to declare.
Note: The keywords une and des are not mandatory: they are approval words..

Describing a "File Description" variable Hide the details

To describe a "File Description" variable:
Use the WLanguage properties specific to the descriptions of data files. For more details, see the remarks.
To validate the description of a variable of type "File Description ":
Use the HDescribeFile function.
Remarks

Properties specific to the description of data files

The table below presents the properties specific to the description of data files:
Note: Properties in bold followed by an asterisk ( * ) must be initialized when describing a data file programmatically.
Property nameEffect
CtAccessType of access to the file when connecting to a specific table via OLE DB (taking into account the changes made with HConnect)
CtDatabaseOLE DB data source when connecting to a specific table (taking into account the changes made with HConnect)
CtDescribedAccessType of access to the file when connecting to a specific table via OLE DB (ignoring the changes made with HConnect)
CtDescribedCaptionCaption of the connection to the OLE DB data source
CtDescribedDatabaseOLE DB data source when connecting to a specific table (ignoring the changes made with HConnect)
CtDescribedOLEDBProviderName of the OLE DB server (ignoring the changes made with HConnect).
CtDescribedPasswordPassword used to open the file during an OLE DB connection
CtDescribedUserNameName of the user during an OLE DB connection (ignoring the changes made with HConnect).
CtOLEDBProviderName of the OLE DB server used (taking into account the changes made with HConnect).
CtUserNameName of the user during an OLE DB connection (taking into account the changes made by HConnect).
DescribedDirectoryPhysical directory of HFSQL files (this property ignores the changes of directory performed by HChangeDir or HSubstDir).
DescribedNameLogical name of a data file.
DescribedPhysicalNamePhysical name of HFSQL files (while ignoring the changes of name performed by HChangeName).
DirectoryPhysical directory of HFSQL files (this property takes into account the changes of directory performed by HChangeDir or HSubstDir).
FicEncryptionData file encryption mode
FormatFormat of data in the data file (ANSI or Unicode).
HugeFileMaximum size of a data file.
LogDirectoryDirectory of log file described in the analysis.
LogMethodLog mode of a data file.
MmoEncryptionEncryption mode of memo file (.MMO extension) associated with the data file
MmoPackMethodCompression mode of the MMO file (containing text and binary memos) associated with the data file
Name ( * )Name of HFSQL file.
Name55Logical name of a file in Hyper File 5.5 format found in an analysis in WINDEV format.
NdxEncryptionEncryption mode of index file associated with the data file
NullableIndexSupport of NULL values in key items.
NullSupportedSupport of NULL values.
PhysicalNamePhysical name of data files.
RepeatableReadSupportedThe file is used in an HFSQL Client/Server transaction that includes a "Repeatable Read" isolation level.
SecureSecurity level regarding the encryption of data files.
TextItemCompletedFills (or not) the text items with space characters.
TypeType of data file.
UnalterableUnalterability of data files.
WDD55Path of the WDD file in 5.5 format used to handle the data files in 5.5 format in a WINDEV application.
WDD55PasswordPassword used to manipulate a file programmatically defined in Hyper File 5.5 format in a WINDEV analysis.

How to describe data files programmatically?

To describe data files programmatically:
  1. Declare the "File Description", "Item Description", "FullTextIndex Description" and "Link description" variables (if necessary).
  2. For each data file:
  3. If necessary, describe the characteristics of the links using HFSQL properties.
  4. If necessary, validate the description of each link (HDescribeLink).

Handling the items of a data file described programmatically

When creating a data file in the data model editor, the names of the data files and items are automatically recognized by the compiler.
When creating a data file using a "File Description" variable, the names of the data file and its items can be defined with the Name property. These names are not automatically recognized by the compiler. A compilation error occurs if these names are used to identify the data file or the items.
The name of the data file must be declared as data source using the data source keyword, for the compiler to recognize this name. This data file can be handled by its name in the code editor.
For example:
UnFichier is File Description
...
UnFichier.Nom = "CLIENT"
...
HDescribeFile("CLIENT")
...
CLIENT is Data Source
...
HReadFirst(CLIENT, "NOMCLI")
Remark: It is also possible to declare the name of the data file with the keyword Extern.. However, the process execution will be slower.

LogMethod

When the data file is described programmatically:
  • if the data file is logged and if no item is logged, all the items (except for the composite keys) are automatically logged.
  • if the data file is logged and if at least one item is logged, the other items are not modified.
Minimum version required
  • Version 9
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Last update: 09/20/2024

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