<Source>.CancelDeclaration (Function)

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Conditions for using <Source>.CancelDeclaration
<Source>.CancelDeclaration and closing the data file

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<Source>.CancelDeclaration (Function)

In french: <Source>.AnnuleDéclaration

Not available with this kind of connection

Allows you to:

Delete a declaration previously made with <Source>.Declare, <Source>.DeclareExternal, <Source>.DescribeFile. After this operation, the data file is no longer recognized by the HFSQL engine.
Free the resources of a query (after calling <Source>.ExecuteQuery or <Source>.ExecuteSQLQuery).

Example

// Le fichier de données Client a été précédemment déclaré dans l'analyse 
// par la fonction HDéclareExterne
Client.Ferme()
Client.AnnuleDéclaration()

Syntax

<Result> = <Source>.CancelDeclaration()

<Result>: Boolean

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

<Source>: Type corresponding to the specified source

Corresponds to:
the name of data file (defined in the analysis). If this name is not specified, <Source>.CancelDeclaration handles the last data file used.
the name of query or data source associated with a query (when freeing resources once <Source>.ExecuteQuery or <Source>.ExecuteSQLQuery has been used).

Remarks

Conditions for using <Source>.CancelDeclaration

This function must be used ONLY when the relevant data file (or query) is not used anymore!

In the following example, the <Source>.CancelDeclaration function is used too early: the contents of the Table control will be completely distorted.. The Table control is populated using BuildBrowsingTable in a parallel process in the background. Therefore, <Source>.CancelDeclaration will be called before the table is entirely filled, making this table unusable.

HExecuteSQLQuery("test", "select * from client")
BuildBrowsingTable(TABLE_Table1, "test")
HCancelDeclaration("test")

Note The problem can also occur with a variable of type "data source". A "data source" variable declared locally in a process or event (button click, procedure, method, etc.) ONLY exists while this code is run. For this reason, a "warning" is displayed if you use this type of data source: "the data source will be destroyed at the end of this code".

<Source>.CancelDeclaration and closing the data file

To use <Source>.CancelDeclaration on a data file, this data file must be closed.

If a query, a subquery or a view uses the data file, <Source>.CancelDeclaration cannot be executed, even after calling <Source>.Close. The queries or views that are using the data file must be freed beforehand.

Component: wd300hf.dll