qsqldriver.cpp

奇趣公司比较新的qt/emd版本

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#include "qsqldriver.h"

#include "qdatetime.h"
#include "qsqlerror.h"
#include "qsqlfield.h"
#include "qsqlindex.h"
#include "qstringlist.h"
#include "private/qobject_p.h"

class QSqlDriverPrivate : public QObjectPrivate
{
public:
    QSqlDriverPrivate();
    virtual ~QSqlDriverPrivate();

public:
    // @CHECK: this member is never used. It was named q, which expanded to q_func().
    QSqlDriver *q_func();
    uint isOpen : 1;
    uint isOpenError : 1;
    QSqlError error;
};

inline QSqlDriverPrivate::QSqlDriverPrivate()
    : QObjectPrivate(), isOpen(false), isOpenError(false)
{
}

QSqlDriverPrivate::~QSqlDriverPrivate()
{
}

/*!
    \class QSqlDriver
    \brief The QSqlDriver class is an abstract base class for accessing
    specific SQL databases.

    \ingroup database
    \module sql

    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 \l{How to Write Your Own
    Database Driver} for more information.

    \sa QSqlDatabase, QSqlResult
*/

/*!
    Constructs a new driver with the given \a parent.
*/

QSqlDriver::QSqlDriver(QObject *parent)
    : QObject(*new QSqlDriverPrivate, parent)
{
}

/*!
    Destroys the object and frees any allocated resources.
*/

QSqlDriver::~QSqlDriver()
{
}

/*!
    \fn bool QSqlDriver::open(const QString &db, const QString &user, const QString& password,
                              const QString &host, int port, const QString &options)

    Derived classes must reimplement this pure virtual function to
    open a database connection on database \a db, using user name \a
    user, password \a password, host \a host, port \a port and
    connection options \a options.

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

    \sa setOpen()
*/

/*!
    \fn bool QSqlDriver::close()

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

    \sa open(), setOpen()
*/

/*!
    \fn QSqlResult *QSqlDriver::createResult() const

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

bool QSqlDriver::isOpen() const
{
    return d_func()->isOpen;
}

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

bool QSqlDriver::isOpenError() const
{
    return d_func()->isOpenError;
}

/*!
    \enum QSqlDriver::DriverFeature

    This enum contains a list of features a driver might support. Use
    hasFeature() to query whether a feature is supported or not.

    \value Transactions  Whether the driver supports SQL transactions.
    \value QuerySize  Whether the database is capable of reporting the size
    of a query. Note that some databases do not support returning the size
    (i.e. number of rows returned) of a query, in which case
    QSqlQuery::size() will return -1.
    \value BLOB  Whether the driver supports Binary Large Object fields.
    \value Unicode  Whether the driver supports Unicode strings if the
    database server does.
    \value PreparedQueries  Whether the driver supports prepared query execution.
    \value NamedPlaceholders  Whether the driver supports the use of named placeholders.
    \value PositionalPlaceholders  Whether the driver supports the use of positional placeholders.
    \value LastInsertId  Whether the driver supports returning the Id of the last touched row.
    \value BatchOperations  Whether the driver supports batched operations, see QSqlResult::execBatch()
    \value SimpleLocking  Whether the driver disallows a write lock on a table while other queries have a read lock on it.
    \value LowPrecisionNumbers  Whether the driver allows fetching numerical values with low precision.

    More information about supported features can be found in the
    \l{sql-driver.html}{Qt SQL driver} documentation.

    \sa hasFeature()
*/

/*!
    \enum QSqlDriver::StatementType

    This enum contains a list of SQL statement (or clause) types the
    driver can create.

    \value WhereStatement  An SQL \c WHERE statement (e.g., \c{WHERE f = 5}).
    \value SelectStatement An SQL \c SELECT statement (e.g., \c{SELECT f FROM t}).
    \value UpdateStatement An SQL \c UPDATE statement (e.g., \c{UPDATE TABLE t set f = 1}).
    \value InsertStatement An SQL \c INSERT statement (e.g., \c{INSERT INTO t (f) values (1)}).
    \value DeleteStatement An SQL \c DELETE statement (e.g., \c{DELETE FROM t}).

    \sa sqlStatement()
*/

/*!
    \enum QSqlDriver::IdentifierType

    This enum contains a list of SQL identifier types.

    \value FieldName A SQL field name
    \value TableName A SQL table name
*/

/*!
    \fn bool QSqlDriver::hasFeature(DriverFeature feature) const

    Returns true if the driver supports feature \a feature; otherwise
    returns false.

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

    \sa DriverFeature
*/

/*!
    This function sets the open state of the database to \a open.
    Derived classes can use this function to report the status of
    open().

    \sa open(), setOpenError()
*/

void QSqlDriver::setOpen(bool open)
{
    d_func()->isOpen = open;
}

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

    \sa open(), setOpen()
*/

void QSqlDriver::setOpenError(bool error)
{
    d_func()->isOpenError = error;
    if (error)
        d_func()->isOpen = false;
}

/*!
    This function is called to begin a transaction. If successful,
    return true, otherwise return false. The default implementation
    does nothing and returns false.

    \sa commitTransaction(), rollbackTransaction()
*/

bool QSqlDriver::beginTransaction()
{
    return false;
}

/*!
    This function is called to commit a transaction. If successful,
    return true, otherwise return false. The default implementation
    does nothing and returns false.

    \sa beginTransaction(), rollbackTransaction()
*/

bool QSqlDriver::commitTransaction()
{
    return false;
}

/*!
    This function is called to rollback a transaction. If successful,
    return true, otherwise return false. The default implementation
    does nothing and returns false.

    \sa beginTransaction(), commitTransaction()
*/

bool QSqlDriver::rollbackTransaction()
{
    return false;
}

/*!
    This function is used to set the value of the last error, \a error,
    that occurred on the database.

    \sa lastError()
*/

void QSqlDriver::setLastError(const QSqlError &error)
{
    d_func()->error = error;
}

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

QSqlError QSqlDriver::lastError() const
{
    return d_func()->error;
}

/*!
    Returns a list of the names of the tables in the database. The
    default implementation returns an empty list.

    The \a 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.
*/

QStringList QSqlDriver::tables(QSql::TableType) const
{
    return QStringList();
}