The QSqlResult class provides an abstract interface for
accessing data from SQL databases.
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Detailed Description
The QSqlResult class provides an abstract interface for
accessing data from SQL databases.
Normally you would use QSqlQuery instead of QSqlResult since QSqlQuery
provides a generic wrapper for database-specific implementations of
QSqlResult.
See also QSql and Database Classes.
Member Function Documentation
QSqlResult::QSqlResult ( const QSqlDriver * db ) [protected]
Protected constructor which creates a QSqlResult using database db. The object is initialized to an inactive state.
QSqlResult::~QSqlResult () [virtual]
Destroys the object and frees any allocated resources.
int QSqlResult::at () const [protected]
Returns the current (zero-based) position of the result.
QVariant QSqlResult::data ( int i ) [pure virtual protected]
Returns the data for field i (zero-based) as a QVariant. This
function is only called if the result is in an active state and is
positioned on a valid record and i is non-negative.
Derived classes must reimplement this function and return the value
of field i, or QVariant() if it cannot be determined.
const QSqlDriver * QSqlResult::driver () const [protected]
Returns the driver associated with the result.
bool QSqlResult::fetch ( int i ) [pure virtual protected]
Positions the result to an arbitrary (zero-based) index i. This
function is only called if the result is in an active state. Derived
classes must reimplement this function and position the result to the
index i, and call setAt() with an appropriate value. Return TRUE
to indicate success, or FALSE to signify failure.
bool QSqlResult::fetchFirst () [pure virtual protected]
Positions the result to the first record in the result. This
function is only called if the result is in an active state.
Derived classes must reimplement this function and position the result
to the first record, and call setAt() with an appropriate value.
Return TRUE to indicate success, or FALSE to signify failure.
bool QSqlResult::fetchLast () [pure virtual protected]
Positions the result to the last record in the result. This
function is only called if the result is in an active state.
Derived classes must reimplement this function and position the result
to the last record, and call setAt() with an appropriate value.
Return TRUE to indicate success, or FALSE to signify failure.
bool QSqlResult::fetchNext () [virtual protected]
Positions the result to the next available record in the result.
This function is only called if the result is in an active state.
The default implementation calls fetch() with the next index.
Derived classes can reimplement this function and position the result
to the next record in some other way, and call setAt() with an
appropriate value. Return TRUE to indicate success, or FALSE to
signify failure.
bool QSqlResult::fetchPrev () [virtual protected]
Positions the result to the previous available record in the
result. This function is only called if the result is in an active
state. The default implementation calls fetch() with the previous
index. Derived classes can reimplement this function and position the
result to the next record in some other way, and call setAt() with
an appropriate value. Return TRUE to indicate success, or FALSE to
signify failure.
bool QSqlResult::isActive () const [protected]
Returns TRUE if the result has records to be retrieved; otherwise
returns FALSE.
bool QSqlResult::isForwardOnly () const [protected]
Returns TRUE if you can only scroll forward through a result set;
otherwise returns FALSE.
bool QSqlResult::isNull ( int i ) [pure virtual protected]
Returns TRUE if the field at position i is NULL; otherwise
returns FALSE.
bool QSqlResult::isSelect () const [protected]
Returns TRUE if the current result is from a SELECT statement;
otherwise returns FALSE.
bool QSqlResult::isValid () const [protected]
Returns TRUE if the result is positioned on a valid record (that
is, the result is not positioned before the first or after the
last record); otherwise returns FALSE.
QSqlError QSqlResult::lastError () const [protected]
Returns the last error associated with the result.
QString QSqlResult::lastQuery () const [protected]
Returns the current SQL query text, or QString::null if there is none.
int QSqlResult::numRowsAffected () [pure virtual protected]
Returns the number of rows affected by the last query executed.
bool QSqlResult::reset ( const QString & query ) [pure virtual protected]
Sets the result to use the SQL statement query for subsequent
data retrieval. Derived classes must reimplement this function and
apply the query to the database. This function is called only
after the result is set to an inactive state and is positioned
before the first record of the new result. Derived classes should
return TRUE if the query was successful and ready to be used,
or FALSE otherwise.
void QSqlResult::setActive ( bool a ) [virtual protected]
Protected function provided for derived classes to set the
internal active state to the value of a.
See also isActive().
void QSqlResult::setAt ( int at ) [virtual protected]
Protected function provided for derived classes to set the
internal (zero-based) result index to at.
See also at().
void QSqlResult::setForwardOnly ( bool forward ) [virtual protected]
Sets forward only mode to forward. If forward is TRUE only
fetchNext() is allowed for navigating the results. Forward only
mode needs far less memory since results do not have to be cached.
forward only mode is off by default.
See also fetchNext().
void QSqlResult::setLastError ( const QSqlError & e ) [virtual protected]
Protected function provided for derived classes to set the last
error to the value of e.
See also lastError().
void QSqlResult::setQuery ( const QString & query ) [virtual protected]
Sets the current query for the result to query. The result must
be reset() in order to execute the query on the database.
void QSqlResult::setSelect ( bool s ) [virtual protected]
Protected function provided for derived classes to indicate
whether or not the current statement is a SQL SELECT statement.
The s parameter should be TRUE if the statement is a SELECT
statement, or FALSE otherwise.
int QSqlResult::size () [pure virtual protected]
Returns the size of the result or -1 if it cannot be determined.
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