GdaClient

## GdaClient GdaClient — Database client access |

## Synopsis

    enum        GdaClientEvent;
                GdaClientPrivate;
    GdaClient*  gda_client_new                  (void);
    GdaConnection* gda_client_open_connection   (GdaClient *client,
                                                 const gchar *dsn,
                                                 const gchar *username,
                                                 const gchar *password,
                                                 GdaConnectionOptions options);
    GdaConnection* gda_client_open_connection_from_string
                                                (GdaClient *client,
                                                 const gchar *provider_id,
                                                 const gchar *cnc_string,
                                                 GdaConnectionOptions options);
    const GList* gda_client_get_connection_list (GdaClient *client);
    GdaConnection* gda_client_find_connection   (GdaClient *client,
                                                 const gchar *dsn,
                                                 const gchar *username,
                                                 const gchar *password);
    void        gda_client_close_all_connections
                                                (GdaClient *client);
    void        gda_client_notify_event         (GdaClient *client,
                                                 GdaConnection *cnc,
                                                 GdaClientEvent event,
                                                 GdaParameterList *params);
    void        gda_client_notify_error_event   (GdaClient *client,
                                                 GdaConnection *cnc,
                                                 GdaError *error);
    void        gda_client_notify_connection_opened_event
                                                (GdaClient *client,
                                                 GdaConnection *cnc);
    void        gda_client_notify_connection_closed_event
                                                (GdaClient *client,
                                                 GdaConnection *cnc);
    void        gda_client_notify_transaction_started_event
                                                (GdaClient *client,
                                                 GdaConnection *cnc,
                                                 GdaTransaction *xaction);
    void        gda_client_notify_transaction_committed_event
                                                (GdaClient *client,
                                                 GdaConnection *cnc,
                                                 GdaTransaction *xaction);
    void        gda_client_notify_transaction_cancelled_event
                                                (GdaClient *client,
                                                 GdaConnection *cnc,
                                                 GdaTransaction *xaction);
    gboolean    gda_client_begin_transaction    (GdaClient *client,
                                                 GdaTransaction *xaction);
    gboolean    gda_client_commit_transaction   (GdaClient *client,
                                                 GdaTransaction *xaction);
    gboolean    gda_client_rollback_transaction (GdaClient *client,
                                                 GdaTransaction *xaction);

## Description

This class is the main entry point for libgda client applications. It provides the way by which client applications open connections. Thus, before using any other database-oriented function in libgda, applications must create a GdaClient object (via gda_client_new), and, once created, open the connections from it.

GdaClient also provides a way to treat several connections as if they were only one (a connection pool), which allows applications to, for instance, commit/rollback a transaction in all the connections being managed by a unique GdaClient object, or obtain the list of all tables in all opened connections.

## Details

### enum GdaClientEvent

    typedef enum {
    	GDA_CLIENT_EVENT_INVALID,

    	/* events usually notified by the library itself, and which the providers
    	   should notify on very special cases (like a transaction being started
    	   or committed via a BEGIN/COMMIT command directly sent to the
    	   execute_command method on the provider */
    	GDA_CLIENT_EVENT_ERROR,                 /* params: "error" */
    	GDA_CLIENT_EVENT_CONNECTION_OPENED,     /* params: */
    	GDA_CLIENT_EVENT_CONNECTION_CLOSED,     /* params: */
    	GDA_CLIENT_EVENT_TRANSACTION_STARTED,   /* params: "transaction" */
    	GDA_CLIENT_EVENT_TRANSACTION_COMMITTED, /* params: "transaction" */
    	GDA_CLIENT_EVENT_TRANSACTION_CANCELLED, /* params: "transaction" */
    } GdaClientEvent;

### GdaClientPrivate

    typedef struct _GdaClientPrivate GdaClientPrivate;

### gda_client_new ()

    GdaClient*  gda_client_new                  (void);

Creates a new GdaClient object, which is the entry point for libgda client applications. This object, once created, can be used for opening new database connections and activating other services available to GDA clients.

Returns : | the newly created object.

### gda_client_open_connection ()

    GdaConnection* gda_client_open_connection   (GdaClient *client,
                                                 const gchar *dsn,
                                                 const gchar *username,
                                                 const gchar *password,
                                                 GdaConnectionOptions options);

Establishes a connection to a data source. The connection will be opened if no identical connection is available in the GdaClient connection pool, and re-used if available. If you dont want to share the connection, specify GDA_CONNECTION_OPTIONS_DONT_SHARE as one of the flags in the `options` parameter.

This function is the way of opening database connections with libgda.

`client` : | a GdaClient object.
`dsn` : | data source name.
`username` : | user name.
`password` : | password for `username`.
`options` : | options for the connection (see GdaConnectionOptions).
Returns : | the opened connection if successful, `NULL` if there is an error.

### gda_client_open_connection_from_string ()

    GdaConnection* gda_client_open_connection_from_string
                                                (GdaClient *client,
                                                 const gchar *provider_id,
                                                 const gchar *cnc_string,
                                                 GdaConnectionOptions options);

Opens a connection given a provider ID and a connection string. This allows applications to open connections without having to create a data source in the configuration. The format of `cnc_string` is similar to PostgreSQL and MySQL connection strings. It is a ;-separated series of key=value pairs. Do not add extra whitespace after the ; separator. The possible keys depend on the provider, but these keys should work with all providers: USER, PASSWORD, HOST, DATABASE, PORT

`client` : | a GdaClient object.
`provider_id` : | provider ID to connect to.
`cnc_string` : | connection string.
`options` : | options for the connection (see GdaConnectionOptions).
Returns : | the opened connection if successful, `NULL` if there is an error.

### gda_client_get_connection_list ()

    const GList* gda_client_get_connection_list (GdaClient *client);

Gets the list of all open connections in the given GdaClient object. The GList returned is an internal pointer, so DON'T TRY TO FREE IT.

`client` : | a GdaClient object.
Returns : | a GList of GdaConnection objects.

### gda_client_find_connection ()

    GdaConnection* gda_client_find_connection   (GdaClient *client,
                                                 const gchar *dsn,
                                                 const gchar *username,
                                                 const gchar *password);

Looks for an open connection given a data source name (per libgda configuration), a username and a password.

This function iterates over the list of open connections in the given GdaClient and looks for one that matches the given data source name, username and password.

`client` : | a GdaClient object.
`dsn` : | data source name.
`username` : | user name.
`password` : | password for `username`.
Returns : | a pointer to the found connection, or `NULL` if it could not be found.

### gda_client_close_all_connections ()

    void        gda_client_close_all_connections
                                                (GdaClient *client);

Closes all connections opened by the given GdaClient object.

`client` : | a GdaClient object.

### gda_client_notify_event ()

    void        gda_client_notify_event         (GdaClient *client,
                                                 GdaConnection *cnc,
                                                 GdaClientEvent event,
                                                 GdaParameterList *params);

Notifies an event to the given GdaClient's listeners. The event can be anything (see GdaClientEvent) ranging from a connection opening operation, to changes made to a table in an underlying database.

`client` : | a GdaClient object.
`cnc` : | a GdaConnection object where the event has occurred.
`event` : | event ID.
`params` : | parameters associated with the event.

### gda_client_notify_error_event ()

    void        gda_client_notify_error_event   (GdaClient *client,
                                                 GdaConnection *cnc,
                                                 GdaError *error);

Notifies the given GdaClient of the GDA_CLIENT_EVENT_ERROR event.

`client` : | a GdaClient object.
`cnc` : | a GdaConnection object.
`error` : | the error to be notified.

### gda_client_notify_connection_opened_event ()

    void        gda_client_notify_connection_opened_event
                                                (GdaClient *client,
                                                 GdaConnection *cnc);

Notifies the given GdaClient of the GDA_CLIENT_EVENT_CONNECTION_OPENED event.

`client` : | a GdaClient object.
`cnc` : | a GdaConnection object.

### gda_client_notify_connection_closed_event ()

    void        gda_client_notify_connection_closed_event
                                                (GdaClient *client,
                                                 GdaConnection *cnc);

Notifies the given GdaClient of the GDA_CLIENT_EVENT_CONNECTION_CLOSED event.

`client` : | a GdaClient object.
`cnc` : | a GdaConnection object.

### gda_client_notify_transaction_started_event ()

    void        gda_client_notify_transaction_started_event
                                                (GdaClient *client,
                                                 GdaConnection *cnc,
                                                 GdaTransaction *xaction);

Notifies the given GdaClient of the GDA_CLIENT_EVENT_TRANSACTION_STARTED event.

`client` : | a GdaClient object.
`cnc` : | a GdaConnection object.
`xaction` : | a GdaTransaction object.

### gda_client_notify_transaction_committed_event ()

    void        gda_client_notify_transaction_committed_event
                                                (GdaClient *client,
                                                 GdaConnection *cnc,
                                                 GdaTransaction *xaction);

Notifies the given GdaClient of the GDA_CLIENT_EVENT_TRANSACTION_COMMITTED event.

`client` : | a GdaClient object.
`cnc` : | a GdaConnection object.
`xaction` : | a GdaTransaction object.

### gda_client_notify_transaction_cancelled_event ()

    void        gda_client_notify_transaction_cancelled_event
                                                (GdaClient *client,
                                                 GdaConnection *cnc,
                                                 GdaTransaction *xaction);

Notifies the given GdaClient of the GDA_CLIENT_EVENT_TRANSACTION_CANCELLED event.

`client` : | a GdaClient object.
`cnc` : | a GdaConnection object.
`xaction` : | a GdaTransaction object.

### gda_client_begin_transaction ()

    gboolean    gda_client_begin_transaction    (GdaClient *client,
                                                 GdaTransaction *xaction);

Starts a transaction on all connections being managed by the given GdaClient. It is important to note that this operates on all connections opened within a GdaClient, which could not be what you're looking for.

To execute a transaction on a unique connection, use gda_connection_begin_transaction, gda_connection_commit_transaction and gda_connection_rollback_transaction.

`client` : | a GdaClient object.
`xaction` : | a GdaTransaction object.
Returns : | `TRUE` if all transactions could be started successfully, or `FALSE` if one of them fails.

### gda_client_commit_transaction ()

    gboolean    gda_client_commit_transaction   (GdaClient *client,
                                                 GdaTransaction *xaction);

Commits a running transaction on all connections being managed by the given GdaClient. It is important to note that this operates on all connections opened within a GdaClient, which could not be what you're looking for.

To execute a transaction on a unique connection, use gda_connection_begin_transaction, gda_connection_commit_transaction and gda_connection_rollback_transaction.

`client` : | a GdaClient object.
`xaction` : | a GdaTransaction object.
Returns : | `TRUE` if all transactions could be committed successfully, or `FALSE` if one of them fails.

### gda_client_rollback_transaction ()

    gboolean    gda_client_rollback_transaction (GdaClient *client,
                                                 GdaTransaction *xaction);

Cancels a running transaction on all connections being managed by the given GdaClient. It is important to note that this operates on all connections opened within a GdaClient, which could not be what you're looking for.

To execute a transaction on a unique connection, use gda_connection_begin_transaction, gda_connection_commit_transaction and gda_connection_rollback_transaction.

`client` : | a GdaClient object.
`xaction` : | a GdaTransaction object.
Returns : | `TRUE` if all transactions could be cancelled successfully, or `FALSE` if one of them fails.

## See Also

GdaConnection.