HChangeConnection (Function)

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HChangeConnection (Function)

In french: HChangeConnexion

Not available with this kind of connection

Dynamically changes the connection associated with a data file. The new connection must be known and defined during this change. This new connection will be used during the next opening of the data file.

It is thus possible to import an Oracle table description into the analysis and use this description to work on data files in HFSQL format. For more details, see the detailed examples.

Tips::

To handle connections, it is recommended to use a variable of type Connection.
Caution: The order of use of functions for connecting to an HFSQL Client/Server database is important.. For more details, see Optimizing the connection times to the HFSQL Client/Server databases.

Example

See additional examples

// Décrire la nouvelle connexion
HDescribeConnection("MaConnexion", "", "", "Serveur_SQLServer", "dbo", hOledbSQLServer, hOReadWrite, "")
// Ouvrir la nouvelle connexion
HOpenConnection("MaConnexion")
// Indiquer que "Salaires" utilise la nouvelle connexion
HChangeConnection("Salaires", "MaConnexion")
// Commencer le parcours de la table "Salaires" sur SQLServer
HReadFirst("Salaires")
...
// Fermer la connexion
HCloseConnection("MaConnexion")
// Rétablir l'utilisation de la connexion sur Oracle
HChangeConnection("Salaires", "")
// Ouvrir la table "Salaires" sur Oracle
HOpen("Salaires")

Syntax

<Result> = HChangeConnection(<Data file> , <New connection>)

<Result>: Boolean

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

<Data file>: Character string

Name of data file (defined in the analysis) for which the connection must be changed. This data file will be automatically closed in order for its connection to be modified.
If this parameter is set to "*", the process is applied to all known data files, regardless their origin (HFSQL, OLE DB, Native Connector, etc.). This allows you to transform an HFSQL data file into an OLE DB data file for example.
Projects with multiple analyses: data files from different analyses are taken into account.
This parameter can also correspond to the name of a group of files (or custom-folder) defined in the analysis (not available in Android and Android widget).

<New connection>: Character string or Connection variable

New connection to use. This parameter can correspond to:
the name of the connection to a database. This connection has been defined in the data model editor or dynamically with HDescribeConnection. If this parameter corresponds to an empty string (""), the initial connection is automatically used.
the name of the Connection variable that corresponds to the new connection to use.

Remarks

The connection must be known when running HChangeConnection. If the data file is not known when using HChangeConnection, the connection will be changed during the file declaration.
HChangeConnection automatically closes the data file (HClose) whose connection must be modified.
HChangeConnection does not open the data file or the connection. The connection defined with HChangeConnection will be used next time the data file is opened

Related Examples:

Training (WINDEV): WD OLEDB

[ + ] This example presents the access to a database via OLE DB with the WLanguage functions.
The following topics are presented in this example:
1/ the independence between your applications and the database
2/ the connection via OLE DB
Summary of the example supplied with WINDEV:
This example explains how to create an application independent of the database used.
The same application with the same source code accesses a HFSQL file or an Access database via OLE DB.
According to this principle, your applications will be able to access all the available databases.

Component: wd300hf.dll