- 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
- Validity of connection
- Pseudo-connection to HFSQL Classic database
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.
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.
Remark: From version 19, HFSQL is the new name of HyperFileSQL.
// Use User Groupware files with a MySQL database
IF gpwOpenConnection("gpwCt", "Test", "PasswordMySQL", ...
"Apollon_server", "TEST", hNativeAccessMySQL) = False THEN
// The data files of user groupware
// are automatically created
// if the user has rights on MySQL.
nRes is int = gpwOpen()
// If the login failed
IF nRes <> gpwOk THEN
Error("Error at initialization.", ErrorInfo())
// Use the same connection for all data files
// Change the password of user groupware data files
// through programming
// Example with GPWUSER
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.CryptMethod = hCryptNo
// Open the connection
Error(HErrorInfo() + CR + ErrorInfo())
Defining and opening a connection Hide the details
<Result> = gpwOpenConnection(<Connection name> , <User name> [, <Password>] , <Data source> [, <Database>] , <OLE DB provider or Native Connector> [, <Access> [, <Extended information>]] , <Additional options>)
The effective connection opening is not performed by gpwOpenConnection. The function can return True even if the values passed as parameter are incorrect.
- True if the operation was performed,
- False if a problem occurs. HErrorInfo is used to identify the error.
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).
<User name>: Character string
Name of user who connects to the Client/Server database. This parameter is returned by the CtUserName property.
<Password>: Optional character 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.
<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).
- 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 Sybase Access/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|
Caution: To use an OLE DB connection, you must:
- 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. You only have the ability to read the records. No record can be added or deleted.|
|The database can be accessed in read/write. You have the ability to read the records and to 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 indicated as follows: "<Keyword> = <Value>".
Recognized keywords for the Native MySQL Connector:
|Server Port||See the documentation about MySQL (keyword = 'mysql_real_connect') for more details.|
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:|
- RC5_16 for a RC5 encryption (16 rounds).
This parameter can be retrieved using the CtExtendedInfo
<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:
- Location of cursors
|hClientCursor||Cursor managed by MDAC. Offers more features than a server cursor. A client cursor must necessarily be a static cursor.|
|hServerCursor||Cursor managed by the database. This cursor can easily apply the changes performed by the other users to the data.|
- Type of cursor
|hDynamicCursor||Cursor offering a lot of features but consuming a lot of memory. This cursor allows all types of moves. It allows you to access all the modifications, additions and deletions performed by the other users.|
|hForwardOnlyCursor||Fast cursor consuming little memory. The move is performed from the first record to the last one. The data modified by the other users is not visible.|
|hOpenKeysetCursor||Cursor that handles a fixed set of records. Only the keys corresponding to the record are stored and not the records (consumes less memory). The deleted records can no longer be accessed. Modifications performed by other users are visible (but records added are not).|
|hStaticCursor||Makes a copy of all query records in memory (high memory usage). All types of moves are allowed.|
Caution: some types of cursors may not be supported by all the OLE DB providers.
- Lock mode
|hOptimisticCursor||The record is locked when it is updated|
|hPessimisticCursor||The record is locked as soon as it goes into edit mode to be modified.|
|hReadOnlyCursor||The set of records cannot be modified.|
Opening a connection defined by a Connection variable Hide the details
<Result> = gpwOpenConnection(<Connection used>)
- 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.
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).
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, display the description window of connections: on the "Analysis" tab, in the "Connection" group, 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 the attempt to connect with the default password fails, you have the ability to perform a new attempt with another 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.
Validity of connection
behaves like HDescribeConnection
: this function 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
with the same parameters. Therefore, the connection parameters will already be checked when gpwOpenConnection
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