gpwOpenConnection (Function)

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Using a character string for the OLE DB provider
If a failure occurs, the connection description is not stored
Two connections are opened on the server
Connection validity
Pseudo-connection to HFSQL Classic database

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gpwOpenConnection (Function)

In french: gpwOuvreConnexion

Not available with these kinds of connection

Opens a connection to a specific Client/Server database to manage User Groupware files in Client/Server mode. The connection remains open until the end of the application.

gpwOpenConnection sets and opens a connection to the User Groupware data files. To use the same connection for all the data files of the application, use HChangeConnection. Then, gpwOpen is used to specify the location of data files for managing rights as well as the location of data files for identifying the users.

Example

// Use User Groupware files with a MySQL database 
IF gpwOpenConnection("gpwCt", "Test", "PasswordMySQL", ... 
	"Apollon_server", "TEST", hNativeAccessMySQL) = False THEN 
	Error(HErrorInfo()) 
ELSE 
	// The User Groupware data files 
	// are automatically created if the user has the relevant permissions on MySQL. 
	nRes is int = gpwOpen() 
	// If the login failed 
	IF nRes <> gpwOk THEN 
		SWITCH nRes 
			CASE gpwError: 
				Error("Error at initialization.", ErrorInfo()) 
			CASE gpwUnknownUser: 
				Error("Unknown user.") 
			CASE gpwInvalidPassword: 
				Error("Invalid password") 
		END 
	END 
	// Use the same connection for all data files 
	HChangeConnection("*", "gpwCt") 
	Trace(HNbRec(CEDEX)) 
END

// Change the password of the user groupware data files
// Example with GPWUSER
gpwInitAnalysis()
GPWUSER is Data Source
CNT_GPWu_HFCS is Connection
sPasswordGPWu is string = "PCSGPW2001"

// Connection parameters
CNT_GPWu_HFCS.Provider = hAccessHFClientServer
CNT_GPWu_HFCS.User = "UserHFServer"
CNT_GPWu_HFCS.Password = "PasswordHFServer"
CNT_GPWu_HFCS.Server = "HFServer"
CNT_GPWu_HFCS.Database = "GPWu"
CNT_GPWu_HFCS.Encryption = hEncryptionNO

// Open the connection
gpwOpenConnection(CNT_GPWu_HFCS)
HChangeConnection(GPWUSER, CNT_GPWu_HFCS)
HPass(GPWUSER, sPasswordGPWu)
HCreationIfNotFound(GPWUSER)
HChangePassword(GPWUSER, "TEST")

CASE ERROR:
Error(HErrorInfo() + CR + ErrorInfo())

Syntax

Defining and opening a connection Hide the details

<Result> = gpwOpenConnection(<Connection name> , <Username> [, <Password>] , <Data source> [, <Database>] , <OLE DB provider or Native Connector> [, <Access> [, <Extended information>]] , <Additional options>)

<Result>: Boolean

True if the operation was performed,
False if a problem occurs. HErrorInfo is used to identify the error.
The effective connection opening is not performed by gpwOpenConnection. The function can return True even if the values passed as parameter are incorrect.

Use gpwOpen to specify the location of data files for managing rights as well as the location of data files for identifying the users. The directories must be specified in relation to the server directory.

<Connection name>: Character string

Name of new connection to define and to open. This name must not be used by another connection (defined in the analysis, or with HOpenConnection or HDescribeConnection).

<Username>: Character string

Name of user who connects to the Client/Server database. This parameter is returned by the CtUserName property.

<Password>: Optional string or Secret string

Password defined for the connection to the Client/Server database (if this password exists). If no password is required, use an empty string ("") or the NULL keyword.
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.

<Data source>: Character string

Full path of the data source. The connection will be created and opened for this data source. This parameter is returned by the CtDatabase property.

<Database>: Optional character string

Name of database that will be used on the data source. If this parameter is not required, use an empty string (""). This parameter is returned by the CtInitialCatalog property.

<OLE DB provider or Native Connector>: Character string or constant

Name of OLE DB provider used. To easily retrieve the string to use, select "Connection" in the data model editor (see the Notes).

or
one of the following constants:
hAccessHF7 Pseudo-connection to an HFSQL Classic database (single-user or multi-user)
hAccessHFClientServer Connection to an HFSQL Client/Server database
hNativeAccessAS400 Native AS/400 Access/Connector (optional module)
hNativeAccessDB2 Native DB2 Access/Connector (optional module)
hNativeAccessInformix Native Informix Access/Connector (optional module)
hNativeAccessMySQL Native MySQL Access/Connector (optional module)
hNativeAccessOracle Native Oracle Access/Connector (optional module)
hNativeAccessPostgreSQL Native PostgreSQL Access/Connector (optional module)
hNativeAccessProgress Native Progress access (optional module)
hNativeAccessSQLServer Native SQL Server Access/Connector (optional module)
hNativeAccessSybase Native SAP ASE Connector (optional module)
hNativeAccessxBase Native xBase Access/Connector
hODBC OLE DB provider for ODBC.
Used to access an ODBC source declared in the ODBC data sources of Windows.
hOledbAccess97 OLE DB provider for Access 97
hOledbAccess2000 OLE DB provider for Access 2000
hOledbDBase5 OLE DB provider for dBase 5
hOledbExcel97 OLE DB provider for Excel 97
hOledbExcel2000 OLE DB provider for Excel 2000
hOledbLotus4 OLE DB provider for Lotus 4
hOledbOracle OLE DB provider for Oracle
hOledbSQLServer OLE DB provider for SQL Server
Note: To use an OLE DB connection:
install MDAC version 2.6 or later (setup performed by WINDEV or WEBDEV and when creating the setup program)
install the OLE DB provider corresponding to the database used.
This parameter is returned by the CtOLEDBProvider property.

<Access>: Optional constant

Configures the type of access to the database.
hORead The database can be accessed in read-only. It is only possible to read records. It is not possible to add or remove records.
hOReadWrite
(default value) The database can be accessed in read/write. It is possible to read and write new records.

This parameter is returned by the CtAccess property.

<Extended information>: Optional character string

Optional information inserted into the string for connecting to the database. If specific keywords are recognized, the corresponding information is extracted from the connection string. The rest of the connection string is sent to the database. Then, the extracted parameters are processed by the Native Connector or OLE DB access used.
These keywords must be specified using the following format: ".<Keyword> = <Value>".
Recognized keywords for the Native MySQL Connector:
Server Port For more details, see the documentation about MySQL (keyword = 'mysql_real_connect').
Unix Socket
Client Flag

Recognized keywords for the access via an OLE DB provider:
WD Command Timeout Defines the maximum timeout (in seconds) for running a command (command timeout). Cannot be used with the Native MySQL Connector.
WD Connect Timeout Defines the maximum timeout (in seconds) for establishing the connection (connection timeout). Cannot be used with the Native MySQL Connector.

Recognized keywords for the access via HFSQL Client/Server:
ENCRYPTION Enables the encryption of data exchanged between Client and Server. This keyword can take two values:
FAST
RC5_16 to use 16-round RC5 encryption.
This parameter can be retrieved using the CtExtendedInfo property.

<Additional options>: Constant

If this parameter is not specified, the HFSQL engine automatically defines the best parameters to use according to the database accessed and to the OLE DB provider used.
To force some parameters, you have the ability to combine the following constants:
Cursor location
hClientCursor Cursor managed by MDAC. Generally, it offers more features than a server-side cursor. A client-side cursor is always static.
hServerCursor Cursor managed by the database. This cursor can easily reflect changes made to data by other users.
Cursor type
hDynamicCursor This cursor offers many features, but consumes a lot of memory. This cursor supports all types of scrolling. You can access all insert, update and delete operations made by other users.
hForwardOnlyCursor This cursor is fast and consumes little memory. The cursor can only move forward and be scrolled from the first to the last record. Changes made by other users are not visible.
hOpenKeysetCursor This cursor handles a fixed set of records. Only the key of each record is stored and not the actual record (consumes less memory). Deleted records cannot be accessed. Changes made by other users are visible (but added records are not).
hStaticCursor Makes a copy of all query records in memory (high memory consumption). All types of scrolling are supported.
Lock mode
hOptimisticCursor The record is locked when it is updated
hPessimisticCursor The record is locked as soon as it is edited.
hReadOnlyCursor The record set manipulated cannot be modified.
Note: Not all OLE DB providers support all cursor types.
This parameter is returned by the CtCursorOptions property.

Opening a connection defined by a Connection variable Hide the details

<Result> = gpwOpenConnection(<Connection used>)

<Result>: Boolean

True if the operation was performed,
False if a problem occurs. HErrorInfo is used to identify the error.
The effective connection opening is not performed by gpwOpenConnection. The function can return True even if the values passed as parameter are incorrect.
Use gpwOpen to specify the location of data files for managing rights as well as the location of data files for identifying the users. The directories must be specified in relation to the server directory.

<Connection used>: Connection variable

Name of the Connection variable to open. This name must not be used by another connection (defined in the analysis, or with HOpenConnection or HDescribeConnection).

Remarks

Using a character string for the OLE DB provider

To easily find the character string that must be used to define the OLE DB provider, we recommend that you proceed as follows:

In the data model editor, open the connection description window. Go to the "Analysis" pane, "Connection" group and click "Connections".
Select the provider to use ("Connect via" combo box).
The character string corresponding to the provider is displayed. This character string can be used in the syntax 2 instead of constants.

If a failure occurs, the connection description is not stored

If the connection fails to open, the description of this connection is not validated. Therefore, it is possible to redefine a connection with the same name.

For example, if a connection attempt fails with the default password, you can try again with a different password.

Two connections are opened on the server

Two HFSQL contexts are used by the User Groupware. In the HFSQL Control Center, you will notice two connections for a single instance of the application.

Connection validity

gpwOpenConnection works in the same way as HDescribeConnection, i.e., it does not establish the connection immediately.

gpwOpenConnection identifies the connection parameters that will be used thereafter to establish the connection.

To validate this connection, you have the ability to call HOpenConnection before gpwOpenConnection with the same parameters. Therefore, the connection parameters will already be checked when gpwOpenConnection is called.

Pseudo-connection to HFSQL Classic database

OLE DB data files or native data files are described in the data model editor. To handle these descriptions with an HFSQL Classic database, <OLE DB provider or Native Connector> must correspond to the hAccessHF7 constant.

The data files in HFSQL Classic format corresponding to the description of the OLE DB or native files will be created (if necessary) in the directory defined by <Data source>.

Component: wd300gpu.dll