com.trolltech.qt.sql
Class QSqlDriver

java.lang.Object
  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, 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.Signal0, QSignalEmitter.Signal1<A>, QSignalEmitter.Signal2<A,B>, QSignalEmitter.Signal3<A,B,C>, QSignalEmitter.Signal4<A,B,C,D>, QSignalEmitter.Signal5<A,B,C,D,E>, QSignalEmitter.Signal6<A,B,C,D,E,F>, QSignalEmitter.Signal7<A,B,C,D,E,F,G>, QSignalEmitter.Signal8<A,B,C,D,E,F,G,H>, QSignalEmitter.Signal9<A,B,C,D,E,F,G,H,I>
 
Constructor Summary
QSqlDriver()
          Equivalent to QSqlDriver(0).
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)
          Equivalent to formatValue(field, false).
 java.lang.String formatValue(QSqlField field, boolean trimStrings)
          Returns a string representation of the field value for the database.
static QSqlDriver fromNativePointer(QNativePointer nativePointer)
          This function returns the QSqlDriver instance pointed to by nativePointer
 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 f; 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)
          Equivalent to open(db, QString(), QString(), QString(), -1, QString()).
 boolean open(java.lang.String db, java.lang.String user)
          Equivalent to open(db, user, QString(), QString(), -1, QString()).
 boolean open(java.lang.String db, java.lang.String user, java.lang.String password)
          Equivalent to open(db, user, password, QString(), -1, QString()).
 boolean open(java.lang.String db, java.lang.String user, java.lang.String password, java.lang.String host)
          Equivalent to open(db, user, password, host, -1, QString()).
 boolean open(java.lang.String db, java.lang.String user, java.lang.String password, java.lang.String host, int port)
          Equivalent to open(db, user, password, host, port, QString()).
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 connOpts.
 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, e, that occurred on the database.
protected  void setOpen(boolean o)
          This function sets the open state of the database to o.
protected  void setOpenError(boolean e)
          This function sets the open error state of the database to e.
 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<java.lang.String> tables(QSql.TableType tableType)
          Returns a list of the names of the tables in the database.
 
Methods inherited from class com.trolltech.qt.core.QObject
blockSignals, childEvent, children, connectSlotsByName, customEvent, disposeLater, dumpObjectInfo, dumpObjectTree, dynamicPropertyNames, event, eventFilter, findChild, findChild, findChild, findChildren, findChildren, findChildren, findChildren, installEventFilter, isWidgetType, killTimer, moveToThread, objectName, parent, property, removeEventFilter, setObjectName, setParent, setProperty, signalsBlocked, startTimer, thread, timerEvent
 
Methods inherited from class com.trolltech.qt.QtJambiObject
dispose, disposed, finalize, reassignNativeResources, tr, tr, tr
 
Methods inherited from class com.trolltech.qt.QSignalEmitter
disconnect, disconnect, signalSender
 
Methods inherited from class java.lang.Object
clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface com.trolltech.qt.QtJambiInterface
disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership
 

Constructor Detail

QSqlDriver

public QSqlDriver()

Equivalent to QSqlDriver(0).


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

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, 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, 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, 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)

Equivalent to formatValue(field, false).


formatValue

public java.lang.String formatValue(QSqlField field,
                                    boolean trimStrings)

Returns a string representation of the field value for the database. This is used, for example, when constructing INSERT and UPDATE statements.

The default implementation returns the value formatted as a string according to the following rules:

See Also:
QVariant::toString

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 = ...;
    QVariant v = db.driver()->handle();
    if (v.isValid() && 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 = *static_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 f; 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)

Equivalent to open(db, user, password, host, port, QString()).


open

public final boolean open(java.lang.String db,
                          java.lang.String user,
                          java.lang.String password,
                          java.lang.String host)

Equivalent to open(db, user, password, host, -1, QString()).


open

public final boolean open(java.lang.String db,
                          java.lang.String user,
                          java.lang.String password)

Equivalent to open(db, user, password, QString(), -1, QString()).


open

public final boolean open(java.lang.String db,
                          java.lang.String user)

Equivalent to open(db, user, QString(), QString(), -1, QString()).


open

public final boolean open(java.lang.String db)

Equivalent to open(db, QString(), QString(), QString(), -1, QString()).


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 connOpts.

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, commitTransaction

setLastError

protected void setLastError(QSqlError e)

This function is used to set the value of the last error, e, that occurred on the database.

See Also:
lastError

setOpen

protected void setOpen(boolean o)

This function sets the open state of the database to o. Derived classes can use this function to report the status of open.

See Also:
open, setOpenError

setOpenError

protected void setOpenError(boolean e)

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

See Also:
isOpenError, open, 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<java.lang.String> 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.


fromNativePointer

public static QSqlDriver fromNativePointer(QNativePointer nativePointer)
This function returns the QSqlDriver instance pointed to by nativePointer

Parameters:
nativePointer - the QNativePointer of which object should be returned.