QSqlDriver Class Reference

Constructs a new driver with the given parent.

Destroys the object and frees any allocated resources.

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().

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().

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().

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.

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.

See also isIdentifierEscaped().

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:

• If field is character data, the value is returned enclosed in single quotation marks, which is appropriate for many SQL databases. Any embedded single-quote characters are escaped (replaced with two single-quote characters). If trimStrings is true (the default is false), all trailing whitespace is trimmed from the field.
• If field is date/time data, the value is formatted in ISO format and enclosed in single quotation marks. If the date/time data is invalid, "NULL" is returned.
• If field is bytearray data, and the driver can edit binary fields, the value is formatted as a hexadecimal string.
• For any other field type, toString() is called on its value and the result of this is returned.

See also QVariant::toString().

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:

This snippet returns the handle for PostgreSQL or MySQL:

See also QSqlResult::handle().

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.

Returns whether identifier is escaped according to the database rules. identifier can either be a table name or field name, dependent on type.

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

See also stripDelimiters() and escapeIdentifier().

Returns true if the database connection is open; otherwise returns false.

Returns true if the there was an error opening the database connection; otherwise returns false.

Returns a QSqlError object which contains information about the last error that occurred on the database.

See also setLastError().

Returns the current default precision policy for the database connection.

See also QSql::NumericalPrecisionPolicy, setNumericalPrecisionPolicy(), QSqlQuery::numericalPrecisionPolicy(), and QSqlQuery::setNumericalPrecisionPolicy().

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().

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.

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.

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().

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

See also lastError().

Sets the default numerical precision policy used by queries created by this driver to precisionPolicy.

Note: Setting the default precision policy to precisionPolicy doesn't affect any currently active queries.

See also QSql::NumericalPrecisionPolicy, numericalPrecisionPolicy(), QSqlQuery::setNumericalPrecisionPolicy(), and QSqlQuery::numericalPrecisionPolicy().

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().

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().

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.

Returns the identifier with the leading and trailing delimiters removed, identifier can either be a table name or field name, dependent on type. If identifier does not have leading and trailing delimiter characters, identifier is returned without modification.

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

See also isIdentifierEscaped().

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().

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().

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.

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().

Use the other formatValue() overload instead.

sqlStatement() is now used to generate SQL. Use tr("NULL") for example, instead.

Use query.record() instead.

Use record() instead.

Use query.record() instead.