com.trolltech.qt.sql
Class QSqlDriver

java.lang.Object
  extended by com.trolltech.qt.internal.QSignalEmitterInternal
      extended by com.trolltech.qt.QSignalEmitter
          extended by com.trolltech.qt.QtJambiObject
              extended by com.trolltech.qt.core.QObject
                  extended by com.trolltech.qt.sql.QSqlDriver
All Implemented Interfaces:
QtJambiInterface

public abstract class QSqlDriver
extends QObject

The QSqlDriver class is an abstract base class for accessing specific SQL databases. This class should not be used directly. Use QSqlDatabase instead.

If you want to create your own SQL drivers, you can subclass this class and reimplement its pure virtual functions and those virtual functions that you need. See How to Write Your Own Database Driver for more information.

See also:
QSqlDatabase, and QSqlResult.


Nested Class Summary
static class QSqlDriver.DriverFeature
          This enum contains a list of features a driver might support.
static class QSqlDriver.IdentifierType
          This enum contains a list of SQL identifier types.
static class QSqlDriver.StatementType
          This enum contains a list of SQL statement (or clause) types the driver can create.
 
Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter
QSignalEmitter.AbstractSignal, QSignalEmitter.PrivateSignal0, QSignalEmitter.PrivateSignal1, QSignalEmitter.PrivateSignal2, QSignalEmitter.PrivateSignal3, QSignalEmitter.PrivateSignal4, QSignalEmitter.PrivateSignal5, QSignalEmitter.PrivateSignal6, QSignalEmitter.PrivateSignal7, QSignalEmitter.PrivateSignal8, QSignalEmitter.PrivateSignal9, QSignalEmitter.Signal0, QSignalEmitter.Signal1, QSignalEmitter.Signal2, QSignalEmitter.Signal3, QSignalEmitter.Signal4, QSignalEmitter.Signal5, QSignalEmitter.Signal6, QSignalEmitter.Signal7, QSignalEmitter.Signal8, QSignalEmitter.Signal9
 
Nested classes/interfaces inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
com.trolltech.qt.internal.QSignalEmitterInternal.AbstractSignalInternal
 
Field Summary
 QSignalEmitter.Signal1 notification
          This signal takes 1 generic argument(s).
 
Fields inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
currentSender
 
Constructor Summary
QSqlDriver()
          Constructs a new driver with the given parent.
QSqlDriver(QObject parent)
          Constructs a new driver with the given parent.
 
Method Summary
 boolean beginTransaction()
          This function is called to begin a transaction.
abstract  void close()
          Derived classes must reimplement this pure virtual function in order to close the database connection.
 boolean commitTransaction()
          This function is called to commit a transaction.
abstract  QSqlResult createResult()
          Creates an empty SQL result on the database.
 java.lang.String escapeIdentifier(java.lang.String identifier, QSqlDriver.IdentifierType type)
          Returns the identifier escaped according to the database rules.
 java.lang.String formatValue(QSqlField field)
          Use the other formatValue() overload instead.
 java.lang.String formatValue(QSqlField field, boolean trimStrings)
          Use the other formatValue() overload instead.
 java.lang.Object handle()
          Returns the low-level database handle wrapped in a QVariant or an invalid variant if there is no handle.
abstract  boolean hasFeature(QSqlDriver.DriverFeature f)
          Returns true if the driver supports feature feature; otherwise returns false.
 boolean isOpen()
          Returns true if the database connection is open; otherwise returns false.
 boolean isOpenError()
          Returns true if the there was an error opening the database connection; otherwise returns false.
 QSqlError lastError()
          Returns a QSqlError object which contains information about the last error that occurred on the database.
 boolean open(java.lang.String db)
          Derived classes must reimplement this pure virtual function to open a database connection on database db, using user name user, password password, host host, port port and connection options options.
 boolean open(java.lang.String db, java.lang.String user)
          Derived classes must reimplement this pure virtual function to open a database connection on database db, using user name user, password password, host host, port port and connection options options.
 boolean open(java.lang.String db, java.lang.String user, java.lang.String password)
          Derived classes must reimplement this pure virtual function to open a database connection on database db, using user name user, password password, host host, port port and connection options options.
 boolean open(java.lang.String db, java.lang.String user, java.lang.String password, java.lang.String host)
          Derived classes must reimplement this pure virtual function to open a database connection on database db, using user name user, password password, host host, port port and connection options options.
 boolean open(java.lang.String db, java.lang.String user, java.lang.String password, java.lang.String host, int port)
          Derived classes must reimplement this pure virtual function to open a database connection on database db, using user name user, password password, host host, port port and connection options options.
abstract  boolean open(java.lang.String db, java.lang.String user, java.lang.String password, java.lang.String host, int port, java.lang.String connOpts)
          Derived classes must reimplement this pure virtual function to open a database connection on database db, using user name user, password password, host host, port port and connection options options.
 QSqlIndex primaryIndex(java.lang.String tableName)
          Returns the primary index for table tableName.
 QSqlRecord record(java.lang.String tableName)
          Returns a QSqlRecord populated with the names of the fields in table tableName.
 boolean rollbackTransaction()
          This function is called to rollback a transaction.
protected  void setLastError(QSqlError e)
          This function is used to set the value of the last error, error, that occurred on the database.
protected  void setOpen(boolean o)
          This function sets the open state of the database to open.
protected  void setOpenError(boolean e)
          This function sets the open error state of the database to error.
 java.lang.String sqlStatement(QSqlDriver.StatementType type, java.lang.String tableName, QSqlRecord rec, boolean preparedStatement)
          Returns a SQL statement of type type for the table tableName with the values from rec.
 java.util.List subscribedToNotifications()
          Returns a list of the names of the event notifications that are currently subscribed to.
protected  java.util.List subscribedToNotificationsImplementation()
          Returns a list of the names of the event notifications that are currently subscribed to.
 boolean subscribeToNotification(java.lang.String name)
          This function is called to subscribe to event notifications from the database.
protected  boolean subscribeToNotificationImplementation(java.lang.String name)
          This slot is called to subscribe to event notifications from the database.
 java.util.List tables(QSql.TableType tableType)
          Returns a list of the names of the tables in the database.
 boolean unsubscribeFromNotification(java.lang.String name)
          This function is called to unsubscribe from event notifications from the database.
protected  boolean unsubscribeFromNotificationImplementation(java.lang.String name)
          This slot is called to unsubscribe from event notifications from the database.
 
Methods inherited from class com.trolltech.qt.core.QObject
childEvent, children, connectSlotsByName, customEvent, disposeLater, dumpObjectInfo, dumpObjectTree, dynamicPropertyNames, event, eventFilter, findChild, findChild, findChild, findChildren, findChildren, findChildren, findChildren, indexOfProperty, installEventFilter, isWidgetType, killTimer, moveToThread, objectName, parent, properties, property, removeEventFilter, setObjectName, setParent, setProperty, startTimer, timerEvent, toString, userProperty
 
Methods inherited from class com.trolltech.qt.QtJambiObject
dispose, disposed, equals, finalize, reassignNativeResources, tr, tr, tr
 
Methods inherited from class com.trolltech.qt.QSignalEmitter
blockSignals, disconnect, disconnect, signalsBlocked, signalSender, thread
 
Methods inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
__qt_signalInitialization
 
Methods inherited from class java.lang.Object
clone, getClass, hashCode, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface com.trolltech.qt.QtJambiInterface
disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership
 

Field Detail

notification

public final QSignalEmitter.Signal1 notification

This signal takes 1 generic argument(s). We list their type and the name they go by in the description of this signal. <java.lang.String(named: name)>:

This signal is emitted when the database posts an event notification that the driver subscribes to. name identifies the event notification.

See also:
subscribeToNotification().

Constructor Detail

QSqlDriver

public QSqlDriver()
Constructs a new driver with the given parent.


QSqlDriver

public QSqlDriver(QObject parent)
Constructs a new driver with the given parent.

Method Detail

isOpenError

public final boolean isOpenError()
Returns true if the there was an error opening the database connection; otherwise returns false.


lastError

public final QSqlError lastError()
Returns a QSqlError object which contains information about the last error that occurred on the database.

See also:
setLastError().


subscribeToNotification

public final boolean subscribeToNotification(java.lang.String name)
This function is called to subscribe to event notifications from the database. name identifies the event notification.

If successful, return true, otherwise return false.

The database must be open when this function is called. When the database is closed by calling close() all subscribed event notifications are automatically unsubscribed. Note that calling open() on an already open database may implicitly cause close() to be called, which will cause the driver to unsubscribe from all event notifications.

When an event notification identified by name is posted by the database the notification() signal is emitted.

Warning: Because of binary compatibility constraints, this function is not virtual. If you want to provide event notification support in your own QSqlDriver subclass, reimplement the subscribeToNotificationImplementation() slot in your subclass instead. The subscribeToNotification() function will dynamically detect the slot and call it.

See also:
unsubscribeFromNotification(), subscribedToNotifications(), and QSqlDriver::hasFeature().


subscribeToNotificationImplementation

protected final boolean subscribeToNotificationImplementation(java.lang.String name)
This slot is called to subscribe to event notifications from the database. name identifies the event notification.

If successful, return true, otherwise return false.

The database must be open when this slot is called. When the database is closed by calling close() all subscribed event notifications are automatically unsubscribed. Note that calling open() on an already open database may implicitly cause close() to be called, which will cause the driver to unsubscribe from all event notifications.

When an event notification identified by name is posted by the database the notification() signal is emitted.

Reimplement this slot to provide your own QSqlDriver subclass with event notification support; because of binary compatibility constraints, the subscribeToNotification() function (introduced in Qt 4.4) is not virtual. Instead, subscribeToNotification() will dynamically detect and call this slot. The default implementation does nothing and returns false.

See also:
subscribeToNotification().


subscribedToNotifications

public final java.util.List subscribedToNotifications()
Returns a list of the names of the event notifications that are currently subscribed to.

Warning: Because of binary compatibility constraints, this function is not virtual. If you want to provide event notification support in your own QSqlDriver subclass, reimplement the subscribedToNotificationsImplementation() slot in your subclass instead. The subscribedToNotifications() function will dynamically detect the slot and call it.

See also:
subscribeToNotification(), and unsubscribeFromNotification().


subscribedToNotificationsImplementation

protected final java.util.List subscribedToNotificationsImplementation()
Returns a list of the names of the event notifications that are currently subscribed to.

Reimplement this slot to provide your own QSqlDriver subclass with event notification support; because of binary compatibility constraints, the subscribedToNotifications() function (introduced in Qt 4.4) is not virtual. Instead, subscribedToNotifications() will dynamically detect and call this slot. The default implementation simply returns an empty QStringList.

See also:
subscribedToNotifications().


unsubscribeFromNotification

public final boolean unsubscribeFromNotification(java.lang.String name)
This function is called to unsubscribe from event notifications from the database. name identifies the event notification.

If successful, return true, otherwise return false.

The database must be open when this function is called. All subscribed event notifications are automatically unsubscribed from when the close() function is called.

After calling this function the notification() signal will no longer be emitted when an event notification identified by name is posted by the database.

Warning: Because of binary compatibility constraints, this function is not virtual. If you want to provide event notification support in your own QSqlDriver subclass, reimplement the unsubscribeFromNotificationImplementation() slot in your subclass instead. The unsubscribeFromNotification() function will dynamically detect the slot and call it.

See also:
subscribeToNotification(), and subscribedToNotifications().


unsubscribeFromNotificationImplementation

protected final boolean unsubscribeFromNotificationImplementation(java.lang.String name)
This slot is called to unsubscribe from event notifications from the database. name identifies the event notification.

If successful, return true, otherwise return false.

The database must be open when this slot is called. All subscribed event notifications are automatically unsubscribed from when the close() function is called.

After calling this slot the notification() signal will no longer be emitted when an event notification identified by name is posted by the database.

Reimplement this slot to provide your own QSqlDriver subclass with event notification support; because of binary compatibility constraints, the unsubscribeFromNotification() function (introduced in Qt 4.4) is not virtual. Instead, unsubscribeFromNotification() will dynamically detect and call this slot. The default implementation does nothing and returns false.

See also:
unsubscribeFromNotification().


beginTransaction

public boolean beginTransaction()
This function is called to begin a transaction. If successful, return true, otherwise return false. The default implementation does nothing and returns false.

See also:
commitTransaction(), and rollbackTransaction().


close

public abstract void close()
Derived classes must reimplement this pure virtual function in order to close the database connection. Return true on success, false on failure.

See also:
open(), and setOpen().


commitTransaction

public boolean commitTransaction()
This function is called to commit a transaction. If successful, return true, otherwise return false. The default implementation does nothing and returns false.

See also:
beginTransaction(), and rollbackTransaction().


createResult

public abstract QSqlResult createResult()
Creates an empty SQL result on the database. Derived classes must reimplement this function and return a QSqlResult object appropriate for their database to the caller.


escapeIdentifier

public java.lang.String escapeIdentifier(java.lang.String identifier,
                                         QSqlDriver.IdentifierType type)
Returns the identifier escaped according to the database rules. identifier can either be a table name or field name, dependent on type.

The default implementation does nothing.


formatValue

public final java.lang.String formatValue(QSqlField field)
Use the other formatValue() overload instead.


formatValue

public java.lang.String formatValue(QSqlField field,
                                    boolean trimStrings)
Use the other formatValue() overload instead.


handle

public java.lang.Object handle()
Returns the low-level database handle wrapped in a QVariant or an invalid variant if there is no handle.

Warning: Use this with uttermost care and only if you know what you're doing.

Warning: The handle returned here can become a stale pointer if the connection is modified (for example, if you close the connection).

Warning: The handle can be NULL if the connection is not open yet.

The handle returned here is database-dependent, you should query the type name of the variant before accessing it.

This example retrieves the handle for a connection to sqlite:

    QSqlDatabase db = QSqlDatabase.addDatabase("QPSQL");
    QVariant v = db.driver().handle();
    if (v.isValid() && qstrcmp(v.typeName(), "sqlite3*")) {
        // v.data() returns a pointer to the handle
        sqlite3 handle = static_cast<sqlite3 **>(v.data());
        if (handle != 0) { // check that it is not NULL
            ;// ...
        }
    }
This snippet returns the handle for PostgreSQL or MySQL:
    if (v.typeName() == "PGconn*") {
        PGconn handle = tatic_cast<PGconn **>(v.data());
        if (handle != 0)
        ; // ...
    }

    if (v.typeName() == "MYSQL*") {
        MYSQL handle = static_cast<MYSQL **>(v.data());
        if (handle != 0)
        ; // ...
    }

See also:
QSqlResult::handle().


hasFeature

public abstract boolean hasFeature(QSqlDriver.DriverFeature f)
Returns true if the driver supports feature feature; otherwise returns false.

Note that some databases need to be open() before this can be determined.

See also:
DriverFeature .


isOpen

public boolean isOpen()
Returns true if the database connection is open; otherwise returns false.


open

public final boolean open(java.lang.String db,
                          java.lang.String user,
                          java.lang.String password,
                          java.lang.String host,
                          int port)
Derived classes must reimplement this pure virtual function to open a database connection on database db, using user name user, password password, host host, port port and connection options options.

The function must return true on success and false on failure.

See also:
setOpen().


open

public final boolean open(java.lang.String db,
                          java.lang.String user,
                          java.lang.String password,
                          java.lang.String host)
Derived classes must reimplement this pure virtual function to open a database connection on database db, using user name user, password password, host host, port port and connection options options.

The function must return true on success and false on failure.

See also:
setOpen().


open

public final boolean open(java.lang.String db,
                          java.lang.String user,
                          java.lang.String password)
Derived classes must reimplement this pure virtual function to open a database connection on database db, using user name user, password password, host host, port port and connection options options.

The function must return true on success and false on failure.

See also:
setOpen().


open

public final boolean open(java.lang.String db,
                          java.lang.String user)
Derived classes must reimplement this pure virtual function to open a database connection on database db, using user name user, password password, host host, port port and connection options options.

The function must return true on success and false on failure.

See also:
setOpen().


open

public final boolean open(java.lang.String db)
Derived classes must reimplement this pure virtual function to open a database connection on database db, using user name user, password password, host host, port port and connection options options.

The function must return true on success and false on failure.

See also:
setOpen().


open

public abstract boolean open(java.lang.String db,
                             java.lang.String user,
                             java.lang.String password,
                             java.lang.String host,
                             int port,
                             java.lang.String connOpts)
Derived classes must reimplement this pure virtual function to open a database connection on database db, using user name user, password password, host host, port port and connection options options.

The function must return true on success and false on failure.

See also:
setOpen().


primaryIndex

public QSqlIndex primaryIndex(java.lang.String tableName)
Returns the primary index for table tableName. Returns an empty QSqlIndex if the table doesn't have a primary index. The default implementation returns an empty index.


record

public QSqlRecord record(java.lang.String tableName)
Returns a QSqlRecord populated with the names of the fields in table tableName. If no such table exists, an empty record is returned. The default implementation returns an empty record.


rollbackTransaction

public boolean rollbackTransaction()
This function is called to rollback a transaction. If successful, return true, otherwise return false. The default implementation does nothing and returns false.

See also:
beginTransaction(), and commitTransaction().


setLastError

protected void setLastError(QSqlError e)
This function is used to set the value of the last error, error, that occurred on the database.

See also:
lastError().


setOpen

protected void setOpen(boolean o)
This function sets the open state of the database to open. Derived classes can use this function to report the status of open().

See also:
open(), and setOpenError().


setOpenError

protected void setOpenError(boolean e)
This function sets the open error state of the database to error. Derived classes can use this function to report the status of open(). Note that if error is true the open state of the database is set to closed (i.e., isOpen() returns false).

See also:
isOpenError(), open(), and setOpen().


sqlStatement

public java.lang.String sqlStatement(QSqlDriver.StatementType type,
                                     java.lang.String tableName,
                                     QSqlRecord rec,
                                     boolean preparedStatement)
Returns a SQL statement of type type for the table tableName with the values from rec. If preparedStatement is true, the string will contain placeholders instead of values.

This method can be used to manipulate tables without having to worry about database-dependent SQL dialects. For non-prepared statements, the values will be properly escaped.


tables

public java.util.List tables(QSql.TableType tableType)
Returns a list of the names of the tables in the database. The default implementation returns an empty list.

The tableType argument describes what types of tables should be returned. Due to binary compatibility, the string contains the value of the enum QSql::TableTypes as text. An empty string should be treated as QSql::Tables for backward compatibility.