source: trunk/src/sql/kernel/qsqlfield.cpp@ 135

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#include "qsqlfield.h"
#include "qatomic.h"
#include "qdebug.h"

QT_BEGIN_NAMESPACE

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
                && gen == other.gen
                && autoval == other.autoval);
    }

    QAtomicInt 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
    \inmodule QtSql

    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:

    \snippet doc/src/snippets/sqldatabase/sqldatabase.cpp 2

    However, the field will attempt to cast certain data types to the
    field data type where possible:

    \snippet doc/src/snippets/sqldatabase/sqldatabase.cpp 3

    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:

    \snippet doc/src/snippets/sqldatabase/sqldatabase.cpp 4
    \dots
    \snippet doc/src/snippets/sqldatabase/sqldatabase.cpp 5
    \snippet doc/src/snippets/sqldatabase/sqldatabase.cpp 6

    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