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Diffstat (limited to 'src/sql/models/qsqlrelationaltablemodel.cpp')
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diff --git a/src/sql/models/qsqlrelationaltablemodel.cpp b/src/sql/models/qsqlrelationaltablemodel.cpp new file mode 100644 index 0000000..935466b --- /dev/null +++ b/src/sql/models/qsqlrelationaltablemodel.cpp @@ -0,0 +1,717 @@ +/**************************************************************************** +** +** 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 "qsqlrelationaltablemodel.h" + +#include "qhash.h" +#include "qstringlist.h" +#include "qsqldatabase.h" +#include "qsqldriver.h" +#include "qsqlerror.h" +#include "qsqlfield.h" +#include "qsqlindex.h" +#include "qsqlquery.h" +#include "qsqlrecord.h" + +#include "qsqltablemodel_p.h" + +#include "qdebug.h" + +QT_BEGIN_NAMESPACE + +/*! + \class QSqlRelation + \brief The QSqlRelation class stores information about an SQL foreign key. + + QSqlRelation is a helper class for QSqlRelationalTableModel. See + QSqlRelationalTableModel::setRelation() and + QSqlRelationalTableModel::relation() for details. + + \sa QSqlRelationalTableModel, QSqlRelationalDelegate, + {Relational Table Model Example} +*/ + +/*! + \fn QSqlRelation::QSqlRelation() + + Constructs an invalid QSqlRelation object. + + For such an object, the tableName(), indexColumn(), and + displayColumn() functions return an empty string. + + \sa isValid() +*/ + +/*! + \fn QSqlRelation::QSqlRelation(const QString &tableName, const QString &indexColumn, + const QString &displayColumn) + + Constructs a QSqlRelation object, where \a tableName is the SQL + table name to which a foreign key refers, \a indexColumn is the + foreign key, and \a displayColumn is the field that should be + presented to the user. + + \sa tableName(), indexColumn(), displayColumn() +*/ + +/*! + \fn QString QSqlRelation::tableName() const + + Returns the name of the table to which a foreign key refers. +*/ + +/*! + \fn QString QSqlRelation::indexColumn() const + + Returns the index column from table tableName() to which a + foreign key refers. +*/ + +/*! + \fn QString QSqlRelation::displayColumn() const + + Returns the column from table tableName() that should be + presented to the user instead of a foreign key. +*/ + +/*! + \fn bool QSqlRelation::isValid() const + + Returns true if the QSqlRelation object is valid; otherwise + returns false. +*/ + +struct QRelation +{ + public: + QRelation(): model(0),m_parent(0),m_dictInitialized(false){} + void init(QSqlRelationalTableModel *parent, const QSqlRelation &relation); + + void populateModel(); + + bool isDictionaryInitialized(); + void populateDictionary(); + void clearDictionary(); + + void clear(); + bool isValid(); + + QSqlRelation rel; + QSqlTableModel *model; + QHash<QString, QVariant> dictionary;//maps keys to display values + + private: + QSqlRelationalTableModel *m_parent; + bool m_dictInitialized; +}; + +/* + A QRelation must be initialized before it is considered valid. + Note: population of the model and dictionary are kept separate + from initialization, and are populated on an as needed basis. +*/ +void QRelation::init(QSqlRelationalTableModel *parent, const QSqlRelation &relation) +{ + Q_ASSERT(parent != NULL); + m_parent = parent; + rel = relation; +} + +void QRelation::populateModel() +{ + if (!isValid()) + return; + Q_ASSERT(m_parent != NULL); + + if (!model) { + model = new QSqlTableModel(m_parent, m_parent->database()); + model->setTable(rel.tableName()); + model->select(); + } +} + +bool QRelation::isDictionaryInitialized() +{ + return m_dictInitialized; +} + +void QRelation::populateDictionary() +{ + if (!isValid()) + return; + + if (model == NULL) + populateModel(); + + QSqlRecord record; + for (int i=0; i < model->rowCount(); ++i) { + record = model->record(i); + dictionary[record.field(rel.indexColumn()).value().toString()] = + record.field(rel.displayColumn()).value(); + } + m_dictInitialized = true; +} + +void QRelation::clearDictionary() +{ + dictionary.clear(); + m_dictInitialized = false; +} + +void QRelation::clear() +{ + delete model; + model = 0; + clearDictionary(); +} + +bool QRelation::isValid() +{ + return (rel.isValid() && m_parent != NULL); +} + +class QSqlRelationalTableModelPrivate: public QSqlTableModelPrivate +{ + Q_DECLARE_PUBLIC(QSqlRelationalTableModel) +public: + QSqlRelationalTableModelPrivate() + : QSqlTableModelPrivate() + {} + QString escapedRelationField(const QString &tableName, const QString &fieldName) const; + + int nameToIndex(const QString &name) const; + mutable QVector<QRelation> relations; + QSqlRecord baseRec; // the record without relations + void clearChanges(); + void clearEditBuffer(); + void clearCache(); + void revertCachedRow(int row); + + void translateFieldNames(int row, QSqlRecord &values) const; +}; + +static void qAppendWhereClause(QString &query, const QString &clause1, const QString &clause2) +{ + if (clause1.isEmpty() && clause2.isEmpty()) + return; + if (clause1.isEmpty() || clause2.isEmpty()) + query.append(QLatin1String(" WHERE (")).append(clause1).append(clause2); + else + query.append(QLatin1String(" WHERE (")).append(clause1).append( + QLatin1String(") AND (")).append(clause2); + query.append(QLatin1String(") ")); +} + +void QSqlRelationalTableModelPrivate::clearChanges() +{ + for (int i = 0; i < relations.count(); ++i) { + QRelation &rel = relations[i]; + rel.clear(); + } +} + +void QSqlRelationalTableModelPrivate::revertCachedRow(int row) +{ + QSqlTableModelPrivate::revertCachedRow(row); +} + +int QSqlRelationalTableModelPrivate::nameToIndex(const QString &name) const +{ + return baseRec.indexOf(name); +} + +void QSqlRelationalTableModelPrivate::clearEditBuffer() +{ + editBuffer = baseRec; +} + +/*! + \reimp +*/ +void QSqlRelationalTableModelPrivate::clearCache() +{ + for (int i = 0; i < relations.count(); ++i) + relations[i].clearDictionary(); + + QSqlTableModelPrivate::clearCache(); +} + +/*! + \class QSqlRelationalTableModel + \brief The QSqlRelationalTableModel class provides an editable + data model for a single database table, with foreign key support. + + \ingroup database + \inmodule QtSql + + QSqlRelationalTableModel acts like QSqlTableModel, but allows + columns to be set as foreign keys into other database tables. + + \table + \row \o \inlineimage noforeignkeys.png + \o \inlineimage foreignkeys.png + \endtable + + The screenshot on the left shows a plain QSqlTableModel in a + QTableView. Foreign keys (\c city and \c country) aren't resolved + to human-readable values. The screenshot on the right shows a + QSqlRelationalTableModel, with foreign keys resolved into + human-readable text strings. + + The following code snippet shows how the QSqlRelationalTableModel + was set up: + + \snippet examples/sql/relationaltablemodel/relationaltablemodel.cpp 0 + \codeline + \snippet examples/sql/relationaltablemodel/relationaltablemodel.cpp 1 + \snippet examples/sql/relationaltablemodel/relationaltablemodel.cpp 2 + + The setRelation() function calls establish a relationship between + two tables. The first call specifies that column 2 in table \c + employee is a foreign key that maps with field \c id of table \c + city, and that the view should present the \c{city}'s \c name + field to the user. The second call does something similar with + column 3. + + If you use a read-write QSqlRelationalTableModel, you probably + want to use QSqlRelationalDelegate on the view. Unlike the default + delegate, QSqlRelationalDelegate provides a combobox for fields + that are foreign keys into other tables. To use the class, simply + call QAbstractItemView::setItemDelegate() on the view with an + instance of QSqlRelationalDelegate: + + \snippet examples/sql/relationaltablemodel/relationaltablemodel.cpp 4 + + The \l{sql/relationaltablemodel} example illustrates how to use + QSqlRelationalTableModel in conjunction with + QSqlRelationalDelegate to provide tables with foreigh key + support. + + \image relationaltable.png + + Notes: + + \list + \o The table must have a primary key declared. + \o The table's primary key may not contain a relation to + another table. + \o If a relational table contains keys that refer to non-existent + rows in the referenced table, the rows containing the invalid + keys will not be exposed through the model. The user or the + database is responsible for keeping referential integrity. + \o If a relation's display column name is also used as a column + name in the main table, or if it is used as display column + name in more than one relation it will be aliased. The alias is + is the relation's table name and display column name joined + by an underscore (e.g. tablename_columnname). All occurrences + of the duplicate display column name are aliased when + duplication is detected, but no aliasing is done to the column + names in the main table. The aliasing doesn't affect + QSqlRelation, so QSqlRelation::displayColumn() will return the + original display column name, but QSqlRecord::fieldName() will + return aliases. + \o When using setData() the role should always be Qt::EditRole, + and when using data() the role should always be Qt::DisplayRole. + \endlist + + \sa QSqlRelation, QSqlRelationalDelegate, + {Relational Table Model Example} +*/ + + +/*! + Creates an empty QSqlRelationalTableModel and sets the parent to \a parent + and the database connection to \a db. If \a db is not valid, the + default database connection will be used. +*/ +QSqlRelationalTableModel::QSqlRelationalTableModel(QObject *parent, QSqlDatabase db) + : QSqlTableModel(*new QSqlRelationalTableModelPrivate, parent, db) +{ +} + +/*! + Destroys the object and frees any allocated resources. +*/ +QSqlRelationalTableModel::~QSqlRelationalTableModel() +{ +} + +/*! + \reimp +*/ +QVariant QSqlRelationalTableModel::data(const QModelIndex &index, int role) const +{ + Q_D(const QSqlRelationalTableModel); + + if (role == Qt::DisplayRole && index.column() > 0 && index.column() < d->relations.count() && + d->relations.value(index.column()).isValid()) { + QRelation &relation = d->relations[index.column()]; + if (!relation.isDictionaryInitialized()) + relation.populateDictionary(); + + //only perform a dictionary lookup for the display value + //when the value at index has been changed or added. + //At an unmodified index, the underlying model will + //already have the correct display value. + QVariant v; + switch (d->strategy) { + case OnFieldChange: + break; + case OnRowChange: + if (index.row() == d->editIndex || index.row() == d->insertIndex) { + v = d->editBuffer.value(index.column()); + } + break; + case OnManualSubmit: + const QSqlTableModelPrivate::ModifiedRow row = d->cache.value(index.row()); + v = row.rec.value(index.column()); + break; + } + if (v.isValid()) + return relation.dictionary[v.toString()]; + } + return QSqlTableModel::data(index, role); +} + +/*! + Sets the data for the \a role in the item with the specified \a + index to the \a value given. Depending on the edit strategy, the + value might be applied to the database at once, or it may be + cached in the model. + + Returns true if the value could be set, or false on error (for + example, if \a index is out of bounds). + + For relational columns, \a value must be the index, not the + display value. The index must also exist in the referenced + table, otherwise the function returns false. + + \sa editStrategy(), data(), submit(), revertRow() +*/ +bool QSqlRelationalTableModel::setData(const QModelIndex &index, const QVariant &value, + int role) +{ + Q_D(QSqlRelationalTableModel); + if ( role == Qt::EditRole && index.column() > 0 && index.column() < d->relations.count() + && d->relations.value(index.column()).isValid()) { + QRelation &relation = d->relations[index.column()]; + if (!relation.isDictionaryInitialized()) + relation.populateDictionary(); + if (!relation.dictionary.contains(value.toString())) + return false; + } + return QSqlTableModel::setData(index, value, role); +} + +/*! + Lets the specified \a column be a foreign index specified by \a relation. + + Example: + + \snippet examples/sql/relationaltablemodel/relationaltablemodel.cpp 0 + \codeline + \snippet examples/sql/relationaltablemodel/relationaltablemodel.cpp 1 + + The setRelation() call specifies that column 2 in table \c + employee is a foreign key that maps with field \c id of table \c + city, and that the view should present the \c{city}'s \c name + field to the user. + + Note: The table's primary key may not contain a relation to another table. + + \sa relation() +*/ +void QSqlRelationalTableModel::setRelation(int column, const QSqlRelation &relation) +{ + Q_D(QSqlRelationalTableModel); + if (column < 0) + return; + if (d->relations.size() <= column) + d->relations.resize(column + 1); + d->relations[column].init(this, relation); +} + +/*! + Returns the relation for the column \a column, or an invalid + relation if no relation is set. + + \sa setRelation(), QSqlRelation::isValid() +*/ +QSqlRelation QSqlRelationalTableModel::relation(int column) const +{ + Q_D(const QSqlRelationalTableModel); + return d->relations.value(column).rel; +} + +QString QSqlRelationalTableModelPrivate::escapedRelationField(const QString &tableName, + const QString &fieldName) const +{ + QString esc; + esc.reserve(tableName.size() + fieldName.size() + 1); + esc.append(tableName).append(QLatin1Char('.')).append(fieldName); + + return db.driver()->escapeIdentifier(esc, QSqlDriver::FieldName); +} + +/*! + \reimp +*/ +QString QSqlRelationalTableModel::selectStatement() const +{ + Q_D(const QSqlRelationalTableModel); + QString query; + + if (tableName().isEmpty()) + return query; + if (d->relations.isEmpty()) + return QSqlTableModel::selectStatement(); + + QString tList; + QString fList; + QString where; + + QSqlRecord rec = d->baseRec; + QStringList tables; + const QRelation nullRelation; + + // Count how many times each field name occurs in the record + QHash<QString, int> fieldNames; + for (int i = 0; i < rec.count(); ++i) { + QSqlRelation relation = d->relations.value(i, nullRelation).rel; + QString name; + if (relation.isValid()) + // Count the display column name, not the original foreign key + name = relation.displayColumn(); + else + name = rec.fieldName(i); + fieldNames.insert(name, fieldNames.value(name, 0) + 1); + } + + for (int i = 0; i < rec.count(); ++i) { + QSqlRelation relation = d->relations.value(i, nullRelation).rel; + if (relation.isValid()) { + QString relTableAlias = QString::fromLatin1("relTblAl_%1").arg(i); + if (!fList.isEmpty()) + fList.append(QLatin1String(", ")); + fList.append(d->escapedRelationField(relTableAlias, relation.displayColumn())); + + // If there are duplicate field names they must be aliased + if (fieldNames.value(relation.displayColumn()) > 1) { + fList.append(QString::fromLatin1(" AS %1_%2").arg(relation.tableName()).arg(relation.displayColumn())); + } + + // this needs fixing!! the below if is borken. + if (!tables.contains(relation.tableName())) + tables.append(d->db.driver()->escapeIdentifier(relation.tableName(),QSqlDriver::TableName) + .append(QLatin1String(" ")) + .append(d->db.driver()->escapeIdentifier(relTableAlias, QSqlDriver::TableName))); + if(!where.isEmpty()) + where.append(QLatin1String(" AND ")); + where.append(d->escapedRelationField(tableName(), rec.fieldName(i))); + where.append(QLatin1String(" = ")); + where.append(d->escapedRelationField(relTableAlias, relation.indexColumn())); + } else { + if (!fList.isEmpty()) + fList.append(QLatin1String(", ")); + fList.append(d->escapedRelationField(tableName(), rec.fieldName(i))); + } + } + if (!tables.isEmpty()) + tList.append(tables.join(QLatin1String(", "))); + if (fList.isEmpty()) + return query; + if(!tList.isEmpty()) + tList.prepend(QLatin1String(", ")); + tList.prepend(d->db.driver()->escapeIdentifier(tableName(),QSqlDriver::TableName)); + query.append(QLatin1String("SELECT ")); + query.append(fList).append(QLatin1String(" FROM ")).append(tList); + qAppendWhereClause(query, where, filter()); + + QString orderBy = orderByClause(); + if (!orderBy.isEmpty()) + query.append(QLatin1Char(' ')).append(orderBy); + + return query; +} + +/*! + Returns a QSqlTableModel object for accessing the table for which + \a column is a foreign key, or 0 if there is no relation for the + given \a column. + + The returned object is owned by the QSqlRelationalTableModel. + + \sa setRelation(), relation() +*/ +QSqlTableModel *QSqlRelationalTableModel::relationModel(int column) const +{ + Q_D(const QSqlRelationalTableModel); + if ( column < 0 || column >= d->relations.count()) + return 0; + + QRelation &relation = const_cast<QSqlRelationalTableModelPrivate *>(d)->relations[column]; + if (!relation.isValid()) + return 0; + + if (!relation.model) + relation.populateModel(); + return relation.model; +} + +/*! + \reimp +*/ +void QSqlRelationalTableModel::revertRow(int row) +{ + QSqlTableModel::revertRow(row); +} + +/*! + \reimp +*/ +void QSqlRelationalTableModel::clear() +{ + Q_D(QSqlRelationalTableModel); + d->clearChanges(); + d->relations.clear(); + QSqlTableModel::clear(); +} + +/*! + \reimp +*/ +bool QSqlRelationalTableModel::select() +{ + return QSqlTableModel::select(); +} + +/*! + \reimp +*/ +void QSqlRelationalTableModel::setTable(const QString &table) +{ + Q_D(QSqlRelationalTableModel); + + // memorize the table before applying the relations + d->baseRec = d->db.record(table); + + QSqlTableModel::setTable(table); +} + +/*! \internal + */ +void QSqlRelationalTableModelPrivate::translateFieldNames(int row, QSqlRecord &values) const +{ + Q_Q(const QSqlRelationalTableModel); + + for (int i = 0; i < values.count(); ++i) { + int realCol = q->indexInQuery(q->createIndex(row, i)).column(); + if (realCol != -1 && relations.value(realCol).isValid()) { + QVariant v = values.value(i); + values.replace(i, baseRec.field(realCol)); + values.setValue(i, v); + } + } +} + +/*! + \reimp +*/ +bool QSqlRelationalTableModel::updateRowInTable(int row, const QSqlRecord &values) +{ + Q_D(QSqlRelationalTableModel); + + QSqlRecord rec = values; + d->translateFieldNames(row, rec); + + return QSqlTableModel::updateRowInTable(row, rec); +} + +/*! + \reimp +*/ +bool QSqlRelationalTableModel::insertRowIntoTable(const QSqlRecord &values) +{ + Q_D(QSqlRelationalTableModel); + + QSqlRecord rec = values; + d->translateFieldNames(0, rec); + + return QSqlTableModel::insertRowIntoTable(rec); +} + +/*! + \reimp +*/ +QString QSqlRelationalTableModel::orderByClause() const +{ + Q_D(const QSqlRelationalTableModel); + + const QSqlRelation rel = d->relations.value(d->sortColumn).rel; + if (!rel.isValid()) + return QSqlTableModel::orderByClause(); + + QString s = QLatin1String("ORDER BY "); + s.append(d->escapedRelationField(QLatin1String("relTblAl_") + QString::number(d->sortColumn), + rel.displayColumn())); + s += d->sortOrder == Qt::AscendingOrder ? QLatin1String(" ASC") : QLatin1String(" DESC"); + return s; +} + +/*! + \reimp +*/ +bool QSqlRelationalTableModel::removeColumns(int column, int count, const QModelIndex &parent) +{ + Q_D(QSqlRelationalTableModel); + + if (parent.isValid() || column < 0 || column + count > d->rec.count()) + return false; + + for (int i = 0; i < count; ++i) { + d->baseRec.remove(column); + if (d->relations.count() > column) + d->relations.remove(column); + } + return QSqlTableModel::removeColumns(column, count, parent); +} + +QT_END_NAMESPACE |