cyberduck
5th December 2013, 11:58
Hello,
i have two database questions:
1.) Each user should sees a consistent view of the data. What have i to do
if two or more user have simultaneously access to my database?
2.) What are the right classes to set a QDataWidgetMapper for my database?
I have try to use QSqlTableModel, but the problem is, one dataset can include
data fom the table "Experiment", "Temperatur" and "Qualities". How can i get
a Model for the QDataWidgetMapper to handle this?
9838
QSqlTableModel *model = new QSqlTableModel();
model->setTable("Temperatur");
model->setFilter("ExperimentID=" + QString::number(ID));
model->select();
QDataWidgetMapper *mapper = new QDataWidgetMapper(this);
mapper->setModel(model);
mapper->setItemDelegate(new QSqlRelationalDelegate(this));
mapper->addMapping(min, model->fieldIndex("min"));
mapper->addMapping(max, model->fieldIndex("max"));
mapper->toFirst();
CREATE TABLE [Experiment]
(
[ExperimentID] integer NOT NULL PRIMARY KEY AUTOINCREMENT,
[Name] varchar (100) NOT NULL,
[Date] datetime NOT NULL DEFAULT '0000-00-00'
);
CREATE TABLE [Temperatur]
(
[ExperimentID] integer NOT NULL DEFAULT 0,
[min] integer DEFAULT 0,
[max] integer DEFAULT 0,
[average] integer DEFAULT 0,
...
);
CREATE TABLE[Qualities]
(
[ExperimentID] integer NOT NULL DEFAULT 0,
[material] integer DEFAULT 0,
[fuel] integer DEFAULT 0,
[container] integer DEFAULT 0,
...
);
i have two database questions:
1.) Each user should sees a consistent view of the data. What have i to do
if two or more user have simultaneously access to my database?
2.) What are the right classes to set a QDataWidgetMapper for my database?
I have try to use QSqlTableModel, but the problem is, one dataset can include
data fom the table "Experiment", "Temperatur" and "Qualities". How can i get
a Model for the QDataWidgetMapper to handle this?
9838
QSqlTableModel *model = new QSqlTableModel();
model->setTable("Temperatur");
model->setFilter("ExperimentID=" + QString::number(ID));
model->select();
QDataWidgetMapper *mapper = new QDataWidgetMapper(this);
mapper->setModel(model);
mapper->setItemDelegate(new QSqlRelationalDelegate(this));
mapper->addMapping(min, model->fieldIndex("min"));
mapper->addMapping(max, model->fieldIndex("max"));
mapper->toFirst();
CREATE TABLE [Experiment]
(
[ExperimentID] integer NOT NULL PRIMARY KEY AUTOINCREMENT,
[Name] varchar (100) NOT NULL,
[Date] datetime NOT NULL DEFAULT '0000-00-00'
);
CREATE TABLE [Temperatur]
(
[ExperimentID] integer NOT NULL DEFAULT 0,
[min] integer DEFAULT 0,
[max] integer DEFAULT 0,
[average] integer DEFAULT 0,
...
);
CREATE TABLE[Qualities]
(
[ExperimentID] integer NOT NULL DEFAULT 0,
[material] integer DEFAULT 0,
[fuel] integer DEFAULT 0,
[container] integer DEFAULT 0,
...
);