QSqlQueryModel¶
The
QSqlQueryModel
class provides a read-only data model for SQL result sets. More…
Inherited by: QSqlRelationalTableModel, QSqlTableModel
Synopsis¶
Functions¶
def
beginInsertColumns
(parent, first, last)def
beginInsertRows
(parent, first, last)def
beginRemoveColumns
(parent, first, last)def
beginRemoveRows
(parent, first, last)def
beginResetModel
()def
endInsertColumns
()def
endInsertRows
()def
endRemoveColumns
()def
endRemoveRows
()def
endResetModel
()def
lastError
()def
query
()def
record
()def
record
(row)def
setLastError
(error)def
setQuery
(query)def
setQuery
(query[, db=QSqlDatabase()])
Virtual functions¶
def
clear
()def
indexInQuery
(item)def
queryChange
()
Detailed Description¶
QSqlQueryModel
is a high-level interface for executing SQL statements and traversing the result set. It is built on top of the lower-levelQSqlQuery
and can be used to provide data to view classes such asQTableView
. For example:QSqlQueryModel *model = new QSqlQueryModel; model->setQuery("SELECT name, salary FROM employee"); model->setHeaderData(0, Qt::Horizontal, tr("Name")); model->setHeaderData(1, Qt::Horizontal, tr("Salary")); QTableView *view = new QTableView; view->setModel(model); view->show();We set the model’s query, then we set up the labels displayed in the view header.
QSqlQueryModel
can also be used to access a database programmatically, without binding it to a view:model = QSqlQueryModel() model.setQuery("SELECT * FROM employee") salary = model.record(4).value("salary")The code snippet above extracts the
salary
field from record 4 in the result set of theSELECT
query. Sincesalary
is the 2nd column (or column index 1), we can rewrite the last line as follows:salary = model.data(model.index(4, 2))The model is read-only by default. To make it read-write, you must subclass it and reimplement
setData()
andflags()
. Another option is to useQSqlTableModel
, which provides a read-write model based on a single database table.The querymodel example illustrates how to use
QSqlQueryModel
to display the result of a query. It also shows how to subclassQSqlQueryModel
to customize the contents of the data before showing it to the user, and how to create a read-write model based onQSqlQueryModel
.If the database doesn’t return the number of selected rows in a query, the model will fetch rows incrementally. See
fetchMore()
for more information.See also
QSqlTableModel
QSqlRelationalTableModel
QSqlQuery
Model/View Programming Query Model Example
- class PySide2.QtSql.QSqlQueryModel([parent=None])¶
- param parent:
Creates an empty
QSqlQueryModel
with the givenparent
.
- PySide2.QtSql.QSqlQueryModel.beginInsertColumns(parent, first, last)¶
- Parameters:
parent –
PySide2.QtCore.QModelIndex
first – int
last – int
- PySide2.QtSql.QSqlQueryModel.beginInsertRows(parent, first, last)¶
- Parameters:
parent –
PySide2.QtCore.QModelIndex
first – int
last – int
- PySide2.QtSql.QSqlQueryModel.beginRemoveColumns(parent, first, last)¶
- Parameters:
parent –
PySide2.QtCore.QModelIndex
first – int
last – int
- PySide2.QtSql.QSqlQueryModel.beginRemoveRows(parent, first, last)¶
- Parameters:
parent –
PySide2.QtCore.QModelIndex
first – int
last – int
- PySide2.QtSql.QSqlQueryModel.beginResetModel()¶
- PySide2.QtSql.QSqlQueryModel.clear()¶
Clears the model and releases any acquired resource.
- PySide2.QtSql.QSqlQueryModel.endInsertColumns()¶
- PySide2.QtSql.QSqlQueryModel.endInsertRows()¶
- PySide2.QtSql.QSqlQueryModel.endRemoveColumns()¶
- PySide2.QtSql.QSqlQueryModel.endRemoveRows()¶
- PySide2.QtSql.QSqlQueryModel.endResetModel()¶
- PySide2.QtSql.QSqlQueryModel.indexInQuery(item)¶
- Parameters:
item –
PySide2.QtCore.QModelIndex
- Return type:
Returns the index of the value in the database result set for the given
item
in the model.The return value is identical to
item
if no columns or rows have been inserted, removed, or moved around.Returns an invalid model index if
item
is out of bounds or ifitem
does not point to a value in the result set.See also
indexInQuery()
insertColumns()
removeColumns()
- PySide2.QtSql.QSqlQueryModel.lastError()¶
- Return type:
Returns information about the last error that occurred on the database.
See also
- PySide2.QtSql.QSqlQueryModel.query()¶
- Return type:
Returns the
QSqlQuery
associated with this model.See also
- PySide2.QtSql.QSqlQueryModel.queryChange()¶
This virtual function is called whenever the query changes. The default implementation does nothing.
query()
returns the new query.See also
- PySide2.QtSql.QSqlQueryModel.record()¶
- Return type:
This is an overloaded function.
Returns an empty record containing information about the fields of the current query.
If the model is not initialized, an empty record will be returned.
See also
- PySide2.QtSql.QSqlQueryModel.record(row)
- Parameters:
row – int
- Return type:
Returns the record containing information about the fields of the current query. If
row
is the index of a valid row, the record will be populated with values from that row.If the model is not initialized, an empty record will be returned.
See also
- PySide2.QtSql.QSqlQueryModel.setLastError(error)¶
- Parameters:
error –
PySide2.QtSql.QSqlError
Protected function which allows derived classes to set the value of the last error that occurred on the database to
error
.See also
- PySide2.QtSql.QSqlQueryModel.setQuery(query)¶
- Parameters:
query –
PySide2.QtSql.QSqlQuery
Resets the model and sets the data provider to be the given
query
. Note that the query must be active and must not be isForwardOnly().lastError()
can be used to retrieve verbose information if there was an error setting the query.Note
Calling will remove any inserted columns.
See also
- PySide2.QtSql.QSqlQueryModel.setQuery(query[, db=QSqlDatabase()])
- Parameters:
query – str
This is an overloaded function.
Executes the query
query
for the given database connectiondb
. If no database (or an invalid database) is specified, the default connection is used.lastError()
can be used to retrieve verbose information if there was an error setting the query.Example:
model = QSqlQueryModel() model.setQuery("select * from MyTable") if model.lastError().isValid(): print model.lastError()
See also
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