/******************************************************************************** Copyright (C) 1992-2006 Trolltech ASA. All rights reserved.**** This file is part of the QtSql module of the Qt Toolkit.**** This file may be used under the terms of the GNU General Public** License version 2.0 as published by the Free Software Foundation** and appearing in the file LICENSE.GPL included in the packaging of** this file.  Please review the following information to ensure GNU** General Public Licensing requirements will be met:** http://www.trolltech.com/products/qt/opensource.html**** If you are unsure which license is appropriate for your use, please** review the following information:** http://www.trolltech.com/products/qt/licensing.html or contact the** sales department at sales@trolltech.com.**** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.******************************************************************************/#include "qsqlfield.h"#include "qatomic.h"#include "qdebug.h"class QSqlFieldPrivate{public:    QSqlFieldPrivate(const QString &name,              QVariant::Type type) :        ref(1), nm(name), ro(false), type(type), req(QSqlField::Unknown),        len(-1), prec(-1), tp(-1), gen(true), autoval(false)    {    }    QSqlFieldPrivate(const QSqlFieldPrivate &other)        : ref(1),          nm(other.nm),          ro(other.ro),          type(other.type),          req(other.req),          len(other.len),          prec(other.prec),          def(other.def),          tp(other.tp),          gen(other.gen),          autoval(other.autoval)    {}    bool operator==(const QSqlFieldPrivate& other) const    {        return (nm == other.nm                && ro == other.ro                && type == other.type                && req == other.req                && len == other.len                && prec == other.prec                && def == other.def                && tp == other.tp                && gen == other.gen                && autoval == other.autoval);    }    QAtomic ref;    QString nm;    uint ro: 1;    QVariant::Type type;    QSqlField::RequiredStatus req;    int len;    int prec;    QVariant def;    int tp;    uint gen: 1;    uint autoval: 1;};/*!    \class QSqlField    \brief The QSqlField class manipulates the fields in SQL database tables    and views.    \ingroup database    \ingroup shared    \module sql    QSqlField represents the characteristics of a single column in a    database table or view, such as the data type and column name. A    field also contains the value of the database column, which can be    viewed or changed.    Field data values are stored as QVariants. Using an incompatible    type is not permitted. For example:    \quotefromfile snippets/sqldatabase/sqldatabase.cpp    \skipto QSqlField_snippets    \skipto QSqlField field    \printuntil setValue    However, the field will attempt to cast certain data types to the    field data type where possible:    \skipto QSqlField field    \printuntil setValue    QSqlField objects are rarely created explicitly in application    code. They are usually accessed indirectly through \l{QSqlRecord}s    that already contain a list of fields. For example:    \skipto QSqlQuery query    \printline QSqlQuery query    \dots    \printline QSqlRecord record    \printline QSqlField field    A QSqlField object can provide some meta-data about the field, for    example, its name(), variant type(), length(), precision(),    defaultValue(), typeID(), and its requiredStatus(),    isGenerated() and isReadOnly(). The field's data can be    checked to see if it isNull(), and its value() retrieved. When    editing the data can be set with setValue() or set to NULL with    clear().    \sa QSqlRecord*//*!    \enum QSqlField::RequiredStatus    Specifies whether the field is required or optional.    \value Required  The field must be specified when inserting records.    \value Optional  The fields doesn't have to be specified when inserting records.    \value Unknown  The database driver couldn't determine whether the field is required or                    optional.    \sa requiredStatus()*//*!    Constructs an empty field called \a fieldName of variant type \a    type.    \sa setRequiredStatus() setLength() setPrecision() setDefaultValue() setGenerated() setReadOnly()*/QSqlField::QSqlField(const QString& fieldName, QVariant::Type type){    d = new QSqlFieldPrivate(fieldName, type);}/*!    Constructs a copy of \a other.*/QSqlField::QSqlField(const QSqlField& other){    d = other.d;    d->ref.ref();    val = other.val;}/*!    Sets the field equal to \a other.*/QSqlField& QSqlField::operator=(const QSqlField& other){    qAtomicAssign(d, other.d);    val = other.val;    return *this;}/*! \fn bool QSqlField::operator!=(const QSqlField &other) const    Returns true if the field is unequal to \a other; otherwise returns    false.*//*!    Returns true if the field is equal to \a other; otherwise returns    false.*/bool QSqlField::operator==(const QSqlField& other) const{    return ((d == other.d || *d == *other.d)            && val == other.val);}/*!    Destroys the object and frees any allocated resources.*/QSqlField::~QSqlField(){    if (!d->ref.deref())        delete d;}/*!    Sets the required status of this field to \a required.    \sa requiredStatus() setType() setLength() setPrecision() setDefaultValue() setGenerated() setReadOnly()*/void QSqlField::setRequiredStatus(RequiredStatus required){    detach();    d->req = required;}/*! \fn void QSqlField::setRequired(bool required)    Sets the required status of this field to \l Required if \a    required is true; otherwise sets it to \l Optional.    \sa setRequiredStatus(), requiredStatus()*//*!    Sets the field's length to \a fieldLength. For strings this is the    maximum number of characters the string can hold; the meaning    varies for other types.    \sa length() setType() setRequiredStatus() setPrecision() setDefaultValue() setGenerated() setReadOnly()*/void QSqlField::setLength(int fieldLength){    detach();    d->len = fieldLength;}/*!    Sets the field's \a precision. This only affects numeric fields.    \sa precision() setType() setRequiredStatus() setLength() setDefaultValue() setGenerated() setReadOnly()*/void QSqlField::setPrecision(int precision){    detach();    d->prec = precision;}/*!    Sets the default value used for this field to \a value.    \sa defaultValue() value() setType() setRequiredStatus() setLength() setPrecision() setGenerated() setReadOnly()*/void QSqlField::setDefaultValue(const QVariant &value){    detach();    d->def = value;}/*!    \internal*/void QSqlField::setSqlType(int type){    detach();    d->tp = type;}/*!    Sets the generated state. If \a gen is false, no SQL will    be generated for this field; otherwise, Qt classes such as    QSqlQueryModel and QSqlTableModel will generate SQL for this    field.    \sa isGenerated() setType() setRequiredStatus() setLength() setPrecision() setDefaultValue() setReadOnly()*/void QSqlField::setGenerated(bool gen){    detach();    d->gen = gen;}/*!    Sets the value of the field to \a value. If the field is read-only    (isReadOnly() returns true), nothing happens.    If the data type of \a value differs from the field's current    data type, an attempt is made to cast it to the proper type. This    preserves the data type of the field in the case of assignment,    e.g. a QString to an integer data type.    To set the value to NULL, use clear().    \sa value() isReadOnly() defaultValue()*/void QSqlField::setValue(const QVariant& value){    if (isReadOnly())        return;    val = value;}/*!    Clears the value of the field and sets it to NULL.    If the field is read-only, nothing happens.    \sa setValue() isReadOnly() requiredStatus()*/void QSqlField::clear(){    if (isReadOnly())        return;    val = QVariant(type());}/*!    Sets the name of the field to \a name.    \sa name()*/void QSqlField::setName(const QString& name){    detach();    d->nm = name;}/*!    Sets the read only flag of the field's value to \a readOnly. A    read-only field cannot have its value set with setValue() and    cannot be cleared to NULL with clear().*/void QSqlField::setReadOnly(bool readOnly){    detach();    d->ro = readOnly;}/*!    \fn QVariant QSqlField::value() const    Returns the value of the field as a QVariant.    Use isNull() to check if the field's value is NULL.*//*!    Returns the name of the field.    \sa setName()*/QString QSqlField::name() const{    return d->nm;}/*!    Returns the field's type as stored in the database.    Note that the actual value might have a different type,    Numerical values that are too large to store in a long    int or double are usually stored as strings to prevent    precision loss.    \sa setType()*/QVariant::Type QSqlField::type() const{    return d->type;}/*!    Set's the field's variant type to \a type.    \sa type() setRequiredStatus() setLength() setPrecision() setDefaultValue() setGenerated() setReadOnly()*/void QSqlField::setType(QVariant::Type type){    detach();    d->type = type;}/*!    Returns true if the field's value is read-only; otherwise returns    false.    \sa setReadOnly() type() requiredStatus() length() precision() defaultValue() isGenerated()*/bool QSqlField::isReadOnly() const{ return d->ro; }/*!    Returns true if the field's value is NULL; otherwise returns    false.    \sa value()*/bool QSqlField::isNull() const{ return val.isNull(); }/*! \internal*/void QSqlField::detach(){    qAtomicDetach(d);}/*!    Returns true if this is a required field; otherwise returns false.    An \c INSERT will fail if a required field does not have a value.    \sa setRequiredStatus() type() length() precision() defaultValue() isGenerated()*/QSqlField::RequiredStatus QSqlField::requiredStatus() const{    return d->req;}/*!    Returns the field's length.    If the returned value is negative, it means that the information    is not available from the database.    \sa setLength() type() requiredStatus() precision() defaultValue() isGenerated()*/int QSqlField::length() const{    return d->len;}/*!    Returns the field's precision; this is only meaningful for numeric    types.    If the returned value is negative, it means that the information    is not available from the database.    \sa setPrecision() type() requiredStatus() length() defaultValue() isGenerated()*/int QSqlField::precision() const{    return d->prec;}/*!    Returns the field's default value (which may be NULL).    \sa setDefaultValue() type() requiredStatus() length() precision() isGenerated()*/QVariant QSqlField::defaultValue() const{    return d->def;}/*!    \internal    Returns the type ID for the field.    If the returned value is negative, it means that the information    is not available from the database.*/int QSqlField::typeID() const{    return d->tp;}/*!    Returns true if the field is generated; otherwise returns    false.    \sa setGenerated() type() requiredStatus() length() precision() defaultValue()*/bool QSqlField::isGenerated() const{    return d->gen;}/*!    Returns true if the field's variant type is valid; otherwise    returns false.*/bool QSqlField::isValid() const{    return d->type != QVariant::Invalid;}#ifndef QT_NO_DEBUG_STREAMQDebug operator<<(QDebug dbg, const QSqlField &f){#ifndef Q_BROKEN_DEBUG_STREAM    dbg.nospace() << "QSqlField(" << f.name() << ", " << QVariant::typeToName(f.type());    if (f.length() >= 0)        dbg.nospace() << ", length: " << f.length();    if (f.precision() >= 0)        dbg.nospace() << ", precision: " << f.precision();    if (f.requiredStatus() != QSqlField::Unknown)        dbg.nospace() << ", required: "                      << (f.requiredStatus() == QSqlField::Required ? "yes" : "no");    dbg.nospace() << ", generated: " << (f.isGenerated() ? "yes" : "no");    if (f.typeID() >= 0)        dbg.nospace() << ", typeID: " << f.typeID();    if (!f.defaultValue().isNull())        dbg.nospace() << ", auto-value: \"" << f.defaultValue() << "\"";    dbg.nospace() << ")";    return dbg.space();#else    qWarning("This compiler doesn't support streaming QSqlField to QDebug");    return dbg;    Q_UNUSED(f);#endif}#endif/*!    \fn void QSqlField::setNull()    Use clear() instead.*//*!    Returns true if the value is auto-generated by the database,    for example auto-increment primary key values.    \sa setAutoValue()*/bool QSqlField::isAutoValue() const{    return d->autoval;}/*!    Marks the field as an auto-generated value if \a autoVal    is true.    \sa isAutoValue() */void QSqlField::setAutoValue(bool autoVal){    detach();    d->autoval = autoVal;}