HDeclare (Function)

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Miscellaneous
HDeclare on database schemas from previous versions

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HDeclare (Function)

In french: HDeclare

Not available with this kind of connection

Declares a description of table (found in a database schema) in the current project. This import is temporary and it can be canceled by HCancelDeclaration.

Example

See additional examples

// Declare a SupplierWD table from the SALESMGT database schema
HDeclare("Supplier", "\Examples\SalesMgt\SALESMGT.WDD", "", "SupplierWD")

Syntax

<Result> = HDeclare(<Table> , <Full path of the WDD file> [, <WDD password> [, <Alias> [, <Options>]]])

<Result>: : Boolean

True if the operation was performed,
False if a problem occurs. HError is used to identify the error.

<Table>: Character string

Logical name of the table to import, used in the external database schema.

<Full path of the WDD file>: Character string

Full access path to the database schema file (.WDD file) containing the description of the HFSQL table to import (up to 260 characters).
This file can correspond to a WDD file created by an earlier version of WINDEV or WEBDEV.

<WDD password>: Optional string or Secret string

Password associated with the database schema.
Empty string ("") if no password is used.
New in version 2025
Secret strings: If you use the secret string vault, the type of secret string used for this parameter must be "ANSI or Unicode string".
To learn more about secret strings and how to use the vault, see Secret string vault.

<Alias>: Optional character string

Logical name of the table, used to handle the table. By default, this name corresponds to <table>.
This parameter is necessary if the current database schema already contains a table whose logical name is <table>, or if a <table> has been described by HDeclareExternal or HDescribeFile.Logical name of the table, used to handle the table. By default, this name corresponds <Source>.
This parameter is necessary if the current database schema already contains a table whose logical name is <Source>, or if a <Source> has been described by HDeclareExternal or HDescribeFile.

<Options>: Optional integer constant

Search options:
hDisk
(Default value) The <Full path of WDD> database schema is sought on the disk (most common case).
hWDL The <Full path of WDD> database schema is sought according to the following priorities:
In the main library (.WDL file)
In the different libraries according to the load order, then on disk.
In the main library of the component.
In the secondary libraries of the component according to the load order.

Remarks

Miscellaneous

It is not necessary to have a database schema linked to the current application to import a table description..
All the HFSQL functions can be used on the imported table except for the integrity management.
You can import as many descriptions as necessary.
This function allows you to use tables described in the earlier WINDEV and WEBDEV database schemas (WINDEV 4.1 to 5.5, WEBDEV 1.0 and 1.5).

HDeclare on database schemas from previous versions

The Hyper File engine version 4.1 to 5.5 requires an open database schema to operate (unlike HFSQL Classic), so the database schema of the first table accessed is opened in the Hyper File 5 engine.

An alias name must be used to access a table with the following characteristics:

table of another database schema.
table with the same logical name as one of the tables found in the opened database schema.

Warning Tables described in earlier WINDEV and WEBDEV database schemas (WINDEV 4.1 to 5.5, WEBDEV 1.0 and 1.5) are handled by the Hyper File version 5.5 engine: WD553HF.DLL.
This module exists in 32-bit version only.
Therefore, an application that must view data in format 5.5 (or earlier) must:

necessarily be compiled in 32-bit mode (and not in 64-bit mode),
limit its capabilities to the ones available in WINDEV version 5.5. For example, the constant hWDL constant did not exist in version 5.5: it can therefore not be used on a Hyper File 5.5 file.

Note This function replaces the HAliasExternalfunction, retained for compatibility with WINDEV 5.5.

Component: wd300hf.dll