/**************************************************************************** ** ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). ** Contact: Qt Software Information (qt-info@nokia.com) ** ** This file is part of the QtSql module of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:LGPL$ ** No Commercial Usage ** This file contains pre-release code and may not be distributed. ** You may use this file in accordance with the terms and conditions ** contained in the either Technology Preview License Agreement or the ** Beta Release License Agreement. ** ** GNU Lesser General Public License Usage ** Alternatively, this file may be used under the terms of the GNU Lesser ** General Public License version 2.1 as published by the Free Software ** Foundation and appearing in the file LICENSE.LGPL included in the ** packaging of this file. Please review the following information to ** ensure the GNU Lesser General Public License version 2.1 requirements ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. ** ** In addition, as a special exception, Nokia gives you certain ** additional rights. These rights are described in the Nokia Qt LGPL ** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this ** package. ** ** GNU General Public License Usage ** Alternatively, this file may be used under the terms of the GNU ** General Public License version 3.0 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 the GNU General Public License version 3.0 requirements will be ** met: http://www.gnu.org/copyleft/gpl.html. ** ** If you are unsure which license is appropriate for your use, please ** contact the sales department at qt-sales@nokia.com. ** $QT_END_LICENSE$ ** ****************************************************************************/ #include "qvariant.h" #include "qhash.h" #include "qregexp.h" #include "qsqlerror.h" #include "qsqlfield.h" #include "qsqlrecord.h" #include "qsqlresult.h" #include "qvector.h" #include "qsqldriver.h" #include QT_BEGIN_NAMESPACE struct QHolder { QHolder(const QString& hldr = QString(), int index = -1): holderName(hldr), holderPos(index) {} bool operator==(const QHolder& h) const { return h.holderPos == holderPos && h.holderName == holderName; } bool operator!=(const QHolder& h) const { return h.holderPos != holderPos || h.holderName != holderName; } QString holderName; int holderPos; }; class QSqlResultPrivate { public: QSqlResultPrivate(QSqlResult* d) : q(d), sqldriver(0), idx(QSql::BeforeFirstRow), active(false), isSel(false), forwardOnly(false), precisionPolicy(QSql::LowPrecisionDouble), bindCount(0), binds(QSqlResult::PositionalBinding) {} void clearValues() { values.clear(); bindCount = 0; } void resetBindCount() { bindCount = 0; } void clearIndex() { indexes.clear(); holders.clear(); types.clear(); } void clear() { clearValues(); clearIndex();; } QString positionalToNamedBinding(); QString namedToPositionalBinding(); QString holderAt(int index) const; public: QSqlResult* q; const QSqlDriver* sqldriver; int idx; QString sql; bool active; bool isSel; QSqlError error; bool forwardOnly; QSql::NumericalPrecisionPolicy precisionPolicy; int bindCount; QSqlResult::BindingSyntax binds; QString executedQuery; QHash types; QVector values; typedef QHash IndexMap; IndexMap indexes; typedef QVector QHolderVector; QHolderVector holders; }; QString QSqlResultPrivate::holderAt(int index) const { return indexes.key(index); } // return a unique id for bound names static QString qFieldSerial(int i) { ushort arr[] = { ':', 'f', 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; ushort *ptr = &arr[1]; while (i > 0) { *(++ptr) = 'a' + i % 16; i >>= 4; } return QString::fromUtf16(arr, int(ptr - arr) + 1); } static bool qIsAlnum(QChar ch) { uint u = uint(ch.unicode()); // matches [a-zA-Z0-9_] return u - 'a' < 26 || u - 'A' < 26 || u - '0' < 10 || u == '_'; } QString QSqlResultPrivate::positionalToNamedBinding() { int n = sql.size(); QString result; result.reserve(n * 5 / 4); bool inQuote = false; int count = 0; for (int i = 0; i < n; ++i) { QChar ch = sql.at(i); if (ch == QLatin1Char('?') && !inQuote) { result += qFieldSerial(count++); } else { if (ch == QLatin1Char('\'')) inQuote = !inQuote; result += ch; } } result.squeeze(); return result; } QString QSqlResultPrivate::namedToPositionalBinding() { int n = sql.size(); QString result; result.reserve(n); bool inQuote = false; int count = 0; int i = 0; while (i < n) { QChar ch = sql.at(i); if (ch == QLatin1Char(':') && !inQuote && (i == 0 || sql.at(i - 1) != QLatin1Char(':')) && (i < n - 1 && qIsAlnum(sql.at(i + 1)))) { int pos = i + 2; while (pos < n && qIsAlnum(sql.at(pos))) ++pos; indexes[sql.mid(i, pos - i)] = count++; result += QLatin1Char('?'); i = pos; } else { if (ch == QLatin1Char('\'')) inQuote = !inQuote; result += ch; ++i; } } result.squeeze(); return result; } /*! \class QSqlResult \brief The QSqlResult class provides an abstract interface for accessing data from specific SQL databases. \ingroup database \inmodule QtSql Normally, you would use QSqlQuery instead of QSqlResult, since QSqlQuery provides a generic wrapper for database-specific implementations of QSqlResult. If you are implementing your own SQL driver (by subclassing QSqlDriver), you will need to provide your own QSqlResult subclass that implements all the pure virtual functions and other virtual functions that you need. \sa QSqlDriver */ /*! \enum QSqlResult::BindingSyntax This enum type specifies the different syntaxes for specifying placeholders in prepared queries. \value PositionalBinding Use the ODBC-style positional syntax, with "?" as placeholders. \value NamedBinding Use the Oracle-style syntax with named placeholders (e.g., ":id") \omitvalue BindByPosition \omitvalue BindByName \sa bindingSyntax() */ /*! \enum QSqlResult::VirtualHookOperation \internal */ /*! Creates a QSqlResult using database driver \a db. The object is initialized to an inactive state. \sa isActive(), driver() */ QSqlResult::QSqlResult(const QSqlDriver *db) { d = new QSqlResultPrivate(this); d->sqldriver = db; if(db) { setNumericalPrecisionPolicy(db->numericalPrecisionPolicy()); } } /*! Destroys the object and frees any allocated resources. */ QSqlResult::~QSqlResult() { delete d; } /*! Sets the current query for the result to \a query. You must call reset() to execute the query on the database. \sa reset(), lastQuery() */ void QSqlResult::setQuery(const QString& query) { d->sql = query; } /*! Returns the current SQL query text, or an empty string if there isn't one. \sa setQuery() */ QString QSqlResult::lastQuery() const { return d->sql; } /*! Returns the current (zero-based) row position of the result. May return the special values QSql::BeforeFirstRow or QSql::AfterLastRow. \sa setAt(), isValid() */ int QSqlResult::at() const { return d->idx; } /*! 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. \sa at() */ bool QSqlResult::isValid() const { return d->idx != QSql::BeforeFirstRow && d->idx != QSql::AfterLastRow; } /*! \fn bool QSqlResult::isNull(int index) Returns true if the field at position \a index in the current row is null; otherwise returns false. */ /*! Returns true if the result has records to be retrieved; otherwise returns false. */ bool QSqlResult::isActive() const { return d->active; } /*! This function is provided for derived classes to set the internal (zero-based) row position to \a index. \sa at() */ void QSqlResult::setAt(int index) { d->idx = index; } /*! This function is provided for derived classes to indicate whether or not the current statement is a SQL \c SELECT statement. The \a select parameter should be true if the statement is a \c SELECT statement; otherwise it should be false. \sa isSelect() */ void QSqlResult::setSelect(bool select) { d->isSel = select; } /*! Returns true if the current result is from a \c SELECT statement; otherwise returns false. \sa setSelect() */ bool QSqlResult::isSelect() const { return d->isSel; } /*! Returns the driver associated with the result. This is the object that was passed to the constructor. */ const QSqlDriver *QSqlResult::driver() const { return d->sqldriver; } /*! This function is provided for derived classes to set the internal active state to \a active. \sa isActive() */ void QSqlResult::setActive(bool active) { if (active && d->executedQuery.isEmpty()) d->executedQuery = d->sql; d->active = active; } /*! This function is provided for derived classes to set the last error to \a error. \sa lastError() */ void QSqlResult::setLastError(const QSqlError &error) { d->error = error; } /*! Returns the last error associated with the result. */ QSqlError QSqlResult::lastError() const { return d->error; } /*! \fn int QSqlResult::size() Returns the size of the \c SELECT result, or -1 if it cannot be determined or if the query is not a \c SELECT statement. \sa numRowsAffected() */ /*! \fn int QSqlResult::numRowsAffected() Returns the number of rows affected by the last query executed, or -1 if it cannot be determined or if the query is a \c SELECT statement. \sa size() */ /*! \fn QVariant QSqlResult::data(int index) Returns the data for field \a index in the current row as a QVariant. This function is only called if the result is in an active state and is positioned on a valid record and \a index is non-negative. Derived classes must reimplement this function and return the value of field \a index, or QVariant() if it cannot be determined. */ /*! \fn bool QSqlResult::reset(const QString &query) Sets the result to use the SQL statement \a query for subsequent data retrieval. Derived classes must reimplement this function and apply the \a query to the database. This function is only called 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. \sa setQuery() */ /*! \fn bool QSqlResult::fetch(int index) Positions the result to an arbitrary (zero-based) row \a index. 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 row \a index, and call setAt() with an appropriate value. Return true to indicate success, or false to signify failure. \sa isActive(), fetchFirst(), fetchLast(), fetchNext(), fetchPrevious() */ /*! \fn bool QSqlResult::fetchFirst() Positions the result to the first record (row 0) 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. \sa fetch(), fetchLast() */ /*! \fn bool QSqlResult::fetchLast() Positions the result to the last record (last row) 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. \sa fetch(), fetchFirst() */ /*! Positions the result to the next available record (row) 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. \sa fetch(), fetchPrevious() */ bool QSqlResult::fetchNext() { return fetch(at() + 1); } /*! Positions the result to the previous record (row) 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::fetchPrevious() { return fetch(at() - 1); } /*! Returns true if you can only scroll forward through the result set; otherwise returns false. \sa setForwardOnly() */ bool QSqlResult::isForwardOnly() const { return d->forwardOnly; } /*! Sets forward only mode to \a forward. If \a forward is true, only fetchNext() is allowed for navigating the results. Forward only mode needs much less memory since results do not have to be cached. By default, this feature is disabled. \sa isForwardOnly(), fetchNext() */ void QSqlResult::setForwardOnly(bool forward) { d->forwardOnly = forward; } /*! Prepares the given \a query, using the underlying database functionality where possible. Returns true if the query is prepared successfully; otherwise returns false. \sa prepare() */ bool QSqlResult::savePrepare(const QString& query) { if (!driver()) return false; d->clear(); d->sql = query; if (!driver()->hasFeature(QSqlDriver::PreparedQueries)) return prepare(query); if (driver()->hasFeature(QSqlDriver::NamedPlaceholders)) { // parse the query to memorize parameter location d->namedToPositionalBinding(); d->executedQuery = d->positionalToNamedBinding(); } else { d->executedQuery = d->namedToPositionalBinding(); } return prepare(d->executedQuery); } /*! Prepares the given \a query for execution; the query will normally use placeholders so that it can be executed repeatedly. Returns true if the query is prepared successfully; otherwise returns false. \sa exec() */ bool QSqlResult::prepare(const QString& query) { int n = query.size(); bool inQuote = false; int i = 0; while (i < n) { QChar ch = query.at(i); if (ch == QLatin1Char(':') && !inQuote && (i == 0 || query.at(i - 1) != QLatin1Char(':')) && (i < n - 1 && qIsAlnum(query.at(i + 1)))) { int pos = i + 2; while (pos < n && qIsAlnum(query.at(pos))) ++pos; d->holders.append(QHolder(query.mid(i, pos - i), i)); i = pos; } else { if (ch == QLatin1Char('\'')) inQuote = !inQuote; ++i; } } d->sql = query; return true; // fake prepares should always succeed } /*! Executes the query, returning true if successful; otherwise returns false. \sa prepare() */ bool QSqlResult::exec() { bool ret; // fake preparation - just replace the placeholders.. QString query = lastQuery(); if (d->binds == NamedBinding) { int i; QVariant val; QString holder; for (i = d->holders.count() - 1; i >= 0; --i) { holder = d->holders.at(i).holderName; val = d->values.value(d->indexes.value(holder)); QSqlField f(QLatin1String(""), val.type()); f.setValue(val); query = query.replace(d->holders.at(i).holderPos, holder.length(), driver()->formatValue(f)); } } else { QString val; int i = 0; int idx = 0; for (idx = 0; idx < d->values.count(); ++idx) { i = query.indexOf(QLatin1Char('?'), i); if (i == -1) continue; QVariant var = d->values.value(idx); QSqlField f(QLatin1String(""), var.type()); if (var.isNull()) f.clear(); else f.setValue(var); val = driver()->formatValue(f); query = query.replace(i, 1, driver()->formatValue(f)); i += val.length(); } } // have to retain the original query with placeholders QString orig = lastQuery(); ret = reset(query); d->executedQuery = query; setQuery(orig); d->resetBindCount(); return ret; } /*! Binds the value \a val of parameter type \a paramType to position \a index in the current record (row). \sa addBindValue() */ void QSqlResult::bindValue(int index, const QVariant& val, QSql::ParamType paramType) { d->binds = PositionalBinding; d->indexes[qFieldSerial(index)] = index; if (d->values.count() <= index) d->values.resize(index + 1); d->values[index] = val; if (paramType != QSql::In || !d->types.isEmpty()) d->types[index] = paramType; } /*! \overload Binds the value \a val of parameter type \a paramType to the \a placeholder name in the current record (row). Note that binding an undefined placeholder will result in undefined behavior. */ void QSqlResult::bindValue(const QString& placeholder, const QVariant& val, QSql::ParamType paramType) { d->binds = NamedBinding; // if the index has already been set when doing emulated named // bindings - don't reset it int idx = d->indexes.value(placeholder, -1); if (idx >= 0) { if (d->values.count() <= idx) d->values.resize(idx + 1); d->values[idx] = val; } else { d->values.append(val); idx = d->values.count() - 1; d->indexes[placeholder] = idx; } if (paramType != QSql::In || !d->types.isEmpty()) d->types[idx] = paramType; } /*! Binds the value \a val of parameter type \a paramType to the next available position in the current record (row). \sa bindValue() */ void QSqlResult::addBindValue(const QVariant& val, QSql::ParamType paramType) { d->binds = PositionalBinding; bindValue(d->bindCount, val, paramType); ++d->bindCount; } /*! Returns the value bound at position \a index in the current record (row). \sa bindValue(), boundValues() */ QVariant QSqlResult::boundValue(int index) const { return d->values.value(index); } /*! \overload Returns the value bound by the given \a placeholder name in the current record (row). \sa bindValueType() */ QVariant QSqlResult::boundValue(const QString& placeholder) const { int idx = d->indexes.value(placeholder, -1); return d->values.value(idx); } /*! Returns the parameter type for the value bound at position \a index. \sa boundValue() */ QSql::ParamType QSqlResult::bindValueType(int index) const { return d->types.value(index, QSql::In); } /*! \overload Returns the parameter type for the value bound with the given \a placeholder name. */ QSql::ParamType QSqlResult::bindValueType(const QString& placeholder) const { return d->types.value(d->indexes.value(placeholder, -1), QSql::In); } /*! Returns the number of bound values in the result. \sa boundValues() */ int QSqlResult::boundValueCount() const { return d->values.count(); } /*! Returns a vector of the result's bound values for the current record (row). \sa boundValueCount() */ QVector& QSqlResult::boundValues() const { return d->values; } /*! Returns the binding syntax used by prepared queries. */ QSqlResult::BindingSyntax QSqlResult::bindingSyntax() const { return d->binds; } /*! Clears the entire result set and releases any associated resources. */ void QSqlResult::clear() { d->clear(); } /*! Returns the query that was actually executed. This may differ from the query that was passed, for example if bound values were used with a prepared query and the underlying database doesn't support prepared queries. \sa exec(), setQuery() */ QString QSqlResult::executedQuery() const { return d->executedQuery; } void QSqlResult::resetBindCount() { d->resetBindCount(); } /*! Returns the name of the bound value at position \a index in the current record (row). \sa boundValue() */ QString QSqlResult::boundValueName(int index) const { return d->holderAt(index); } /*! Returns true if at least one of the query's bound values is a \c QSql::Out or a QSql::InOut; otherwise returns false. \sa bindValueType() */ bool QSqlResult::hasOutValues() const { if (d->types.isEmpty()) return false; QHash::ConstIterator it; for (it = d->types.constBegin(); it != d->types.constEnd(); ++it) { if (it.value() != QSql::In) return true; } return false; } /*! Returns the current record if the query is active; otherwise returns an empty QSqlRecord. The default implementation always returns an empty QSqlRecord. \sa isActive() */ QSqlRecord QSqlResult::record() const { return QSqlRecord(); } /*! Returns the object ID of the most recent inserted row if the database supports it. An invalid QVariant will be returned if the query did not insert any value or if the database does not report the id back. If more than one row was touched by the insert, the behavior is undefined. Note that for Oracle databases the row's ROWID will be returned, while for MySQL databases the row's auto-increment field will be returned. \sa QSqlDriver::hasFeature() */ QVariant QSqlResult::lastInsertId() const { return QVariant(); } /*! \internal */ void QSqlResult::virtual_hook(int, void *) { Q_ASSERT(false); } /*! \internal \since 4.2 Executes a prepared query in batch mode if the driver supports it, otherwise emulates a batch execution using bindValue() and exec(). QSqlDriver::hasFeature() can be used to find out whether a driver supports batch execution. Batch execution can be faster for large amounts of data since it reduces network roundtrips. For batch executions, bound values have to be provided as lists of variants (QVariantList). Each list must contain values of the same type. All lists must contain equal amount of values (rows). NULL values are passed in as typed QVariants, for example \c {QVariant(QVariant::Int)} for an integer NULL value. Example: \snippet doc/src/snippets/code/src_sql_kernel_qsqlresult.cpp 0 Here, we insert two rows into a SQL table, with each row containing three values. \sa exec(), QSqlDriver::hasFeature() */ bool QSqlResult::execBatch(bool arrayBind) { if (driver()->hasFeature(QSqlDriver::BatchOperations)) { virtual_hook(BatchOperation, &arrayBind); d->resetBindCount(); return d->error.type() == QSqlError::NoError; } else { QVector values = d->values; if (values.count() == 0) return false; for (int i = 0; i < values.at(0).toList().count(); ++i) { for (int j = 0; j < values.count(); ++j) bindValue(j, values.at(j).toList().at(i), QSql::In); if (!exec()) return false; } return true; } return false; } /*! \internal */ void QSqlResult::detachFromResultSet() { if (driver()->hasFeature(QSqlDriver::FinishQuery) || driver()->hasFeature(QSqlDriver::SimpleLocking)) virtual_hook(DetachFromResultSet, 0); } /*! \internal */ void QSqlResult::setNumericalPrecisionPolicy(QSql::NumericalPrecisionPolicy policy) { d->precisionPolicy = policy; } /*! \internal */ QSql::NumericalPrecisionPolicy QSqlResult::numericalPrecisionPolicy() const { return d->precisionPolicy; } /*! \internal */ bool QSqlResult::nextResult() { if (driver()->hasFeature(QSqlDriver::MultipleResultSets)) { bool result = false; virtual_hook(NextResult, &result); return result; } return false; } /*! Returns the low-level database handle for this result set wrapped in a QVariant or an invalid QVariant 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 result is modified (for example, if you clear it). \warning The handle can be NULL if the result was not executed 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 sqlite result: \snippet doc/src/snippets/code/src_sql_kernel_qsqlresult.cpp 1 This snippet returns the handle for PostgreSQL or MySQL: \snippet doc/src/snippets/code/src_sql_kernel_qsqlresult.cpp 2 \sa QSqlDriver::handle() */ QVariant QSqlResult::handle() const { return QVariant(); } QT_END_NAMESPACE