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    <p>What you want is a proxy model that acts as a bridge between <code>QSql*Model</code> and the view. For that, you need to subclass <code>QAbstractProxyModel</code>. You have to have a consistent way of finding parent-child relationships in proxy model and mapping them to the source model, so that might require keeping some tally in the proxy model.</p> <p>When you are sub-classing <code>QAbstractProxyModel</code>, you need to re-define, at minimum, these methods:</p> <ul> <li>rowCount</li> <li>columnCount</li> <li>parent</li> <li>index</li> <li>data</li> <li>mapToSource</li> <li>mapFromSource</li> </ul> <p>Also, keep in mind that <code>QAbstractProxyModel</code> does not auto-propagate signals through. So, in order to have the view be aware of changes in source model (like insert, delete, update), you need to pass them in the proxy model (while of course, updating your mappings in the proxy model).</p> <p>It will require some work, but in the end you'll have a more flexible structure. And it will eliminate all the stuff that you need to do for synchronizing database and custom <code>QAbstractItemModel</code>.</p> <p><strong>Edit</strong></p> <p>A custom proxy model that groups items from a flat model according to a given column:</p> <pre><code>import sys from collections import namedtuple import random from PyQt4 import QtCore, QtGui groupItem = namedtuple("groupItem",["name","children","index"]) rowItem = namedtuple("rowItem",["groupIndex","random"]) class GrouperProxyModel(QtGui.QAbstractProxyModel): def __init__(self, parent=None): super(GrouperProxyModel, self).__init__(parent) self._rootItem = QtCore.QModelIndex() self._groups = [] # list of groupItems self._groupMap = {} # map of group names to group indexes self._groupIndexes = [] # list of groupIndexes for locating group row self._sourceRows = [] # map of source rows to group index self._groupColumn = 0 # grouping column. def setSourceModel(self, source, groupColumn=0): super(GrouperProxyModel, self).setSourceModel(source) # connect signals self.sourceModel().columnsAboutToBeInserted.connect(self.columnsAboutToBeInserted.emit) self.sourceModel().columnsInserted.connect(self.columnsInserted.emit) self.sourceModel().columnsAboutToBeRemoved.connect(self.columnsAboutToBeRemoved.emit) self.sourceModel().columnsRemoved.connect(self.columnsRemoved.emit) self.sourceModel().rowsInserted.connect(self._rowsInserted) self.sourceModel().rowsRemoved.connect(self._rowsRemoved) self.sourceModel().dataChanged.connect(self._dataChanged) # set grouping self.groupBy(groupColumn) def rowCount(self, parent): if parent == self._rootItem: # root level return len(self._groups) elif parent.internalPointer() == self._rootItem: # children level return len(self._groups[parent.row()].children) else: return 0 def columnCount(self, parent): if self.sourceModel(): return self.sourceModel().columnCount(QtCore.QModelIndex()) else: return 0 def index(self, row, column, parent): if parent == self._rootItem: # this is a group return self.createIndex(row,column,self._rootItem) elif parent.internalPointer() == self._rootItem: return self.createIndex(row,column,self._groups[parent.row()].index) else: return QtCore.QModelIndex() def parent(self, index): parent = index.internalPointer() if parent == self._rootItem: return self._rootItem else: parentRow = self._getGroupRow(parent) return self.createIndex(parentRow,0,self._rootItem) def data(self, index, role): if role == QtCore.Qt.DisplayRole: parent = index.internalPointer() if parent == self._rootItem: return self._groups[index.row()].name else: parentRow = self._getGroupRow(parent) sourceRow = self._sourceRows.index(self._groups[parentRow].children[index.row()]) sourceIndex = self.createIndex(sourceRow, index.column(), 0) return self.sourceModel().data(sourceIndex, role) return None def flags(self, index): return QtCore.Qt.ItemIsEnabled | QtCore.Qt.ItemIsSelectable def headerData(self, section, orientation, role): return self.sourceModel().headerData(section, orientation, role) def mapToSource(self, index): if not index.isValid(): return QtCore.QModelIndex() parent = index.internalPointer() if not parent.isValid(): return QtCore.QModelIndex() elif parent == self._rootItem: return QtCore.QModelIndex() else: rowItem_ = self._groups[parent.row()].children[index.row()] sourceRow = self._sourceRows.index(rowItem_) return self.createIndex(sourceRow, index.column(), QtCore.QModelIndex()) def mapFromSource(self, index): rowItem_ = self._sourceRows[index.row()] groupRow = self._getGroupRow(rowItem_.groupIndex) itemRow = self._groups[groupRow].children.index(rowItem_) return self.createIndex(itemRow,index.column(),self._groupIndexes[groupRow]) def _clearGroups(self): self._groupMap = {} self._groups = [] self._sourceRows = [] def groupBy(self,column=0): self.beginResetModel() self._clearGroups() self._groupColumn = column sourceModel = self.sourceModel() for row in range(sourceModel.rowCount(QtCore.QModelIndex())): groupName = sourceModel.data(self.createIndex(row,column,0), QtCore.Qt.DisplayRole) groupIndex = self._getGroupIndex(groupName) rowItem_ = rowItem(groupIndex,random.random()) self._groups[groupIndex.row()].children.append(rowItem_) self._sourceRows.append(rowItem_) self.endResetModel() def _getGroupIndex(self, groupName): """ return the index for a group denoted with name. if there is no group with given name, create and then return""" if groupName in self._groupMap: return self._groupMap[groupName] else: groupRow = len(self._groupMap) groupIndex = self.createIndex(groupRow,0,self._rootItem) self._groupMap[groupName] = groupIndex self._groups.append(groupItem(groupName,[],groupIndex)) self._groupIndexes.append(groupIndex) self.layoutChanged.emit() return groupIndex def _getGroupRow(self, groupIndex): for i,x in enumerate(self._groupIndexes): if id(groupIndex)==id(x): return i return 0 def _rowsInserted(self, parent, start, end): for row in range(start, end+1): groupName = self.sourceModel().data(self.createIndex(row,self._groupColumn,0), QtCore.Qt.DisplayRole) groupIndex = self._getGroupIndex(groupName) self._getGroupRow(groupIndex) groupItem_ = self._groups[self._getGroupRow(groupIndex)] rowItem_ = rowItem(groupIndex,random.random()) groupItem_.children.append(rowItem_) self._sourceRows.insert(row, rowItem_) self.layoutChanged.emit() def _rowsRemoved(self, parent, start, end): for row in range(start, end+1): rowItem_ = self._sourceRows[start] groupIndex = rowItem_.groupIndex groupItem_ = self._groups[self._getGroupRow(groupIndex)] childrenRow = groupItem_.children.index(rowItem_) groupItem_.children.pop(childrenRow) self._sourceRows.pop(start) if not len(groupItem_.children): # remove the group groupRow = self._getGroupRow(groupIndex) groupName = self._groups[groupRow].name self._groups.pop(groupRow) self._groupIndexes.pop(groupRow) del self._groupMap[groupName] self.layoutChanged.emit() def _dataChanged(self, topLeft, bottomRight): topRow = topLeft.row() bottomRow = bottomRight.row() sourceModel = self.sourceModel() # loop through all the changed data for row in range(topRow,bottomRow+1): oldGroupIndex = self._sourceRows[row].groupIndex oldGroupItem = self._groups[self._getGroupRow(oldGroupIndex)] newGroupName = sourceModel.data(self.createIndex(row,self._groupColumn,0),QtCore.Qt.DisplayRole) if newGroupName != oldGroupItem.name: # move to new group... newGroupIndex = self._getGroupIndex(newGroupName) newGroupItem = self._groups[self._getGroupRow(newGroupIndex)] rowItem_ = self._sourceRows[row] newGroupItem.children.append(rowItem_) # delete from old group oldGroupItem.children.remove(rowItem_) if not len(oldGroupItem.children): # remove the group groupRow = self._getGroupRow(oldGroupItem.index) groupName = oldGroupItem.name self._groups.pop(groupRow) self._groupIndexes.pop(groupRow) del self._groupMap[groupName] self.layoutChanged.emit() </code></pre>
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    1. POqt pyside - qsql*model, qabstractitemmodel and qtreeview interaction
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    1. POqt pyside - qsql*model, qabstractitemmodel and qtreeview interaction
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    1. COThanks for this. I've been doing a bit of research and was coming to the conclusion that QAbstractProxyModel might be the route. It looks very complicated for me at the moment though :)
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      1. USSteven Lee
    2. CO@StevenLee: Right now, I don't have a working example. Sorry. But I'm working on a custom proxy that groups items from a table model (like QSqlTableModel) based on a given column. If you like, I can share it when I'm done.
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    3. COThat would be very much appreciated. Thanks
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Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

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