Examples of org.xorm.datastore.Row

org.xorm.datastore.Row

A row represents a single instance of a data object. The structure of a Row is defined by its reference to a Table. The terms Row and Table could be changed to "Data Object" and "Datatype"; they were chosen to correspond to a relational database notion but are in no way tied to any particular implementation. A Row contains only primitive values; that is, there are no references to first class objects. When used with a relational database, an instance of the Row class is meant to correspond exactly with a single row in a database table. Foreign keys and primary keys are typically expressed as numeric IDs. Each instance of a Row tracks values for each Column specified for a Table. The column values may or may not have been loaded from persistent storage. This can be tested for using the containsValue() method. If the value has been set -- even to null -- containsValue() will return "true". A row also tracks dirty bits for each Column. A value is said to be dirty if it has been changed since the first time it was set. DatastoreDriver implementations are encouraged to use this information to optimize the update() operation. Finally, a Row is said to be "hollow" if no values other than the primary key have been set. Because it is possible to have a Table without a primary key (for example, a many-to-many table in a relational database), the getPrimaryKeyValue() method is not guaranteed to return a value.

        Table table = classMapping.getTable();


        boolean useNontrans = useNontransactionalRead();


        // 1. Look in cache
        Row row = getFromCache(table, primaryKey);
        if (row == null) {


            // 2. Look in datastore


            // Get the DataFetchGroup to use.

            selector.require(dfg);
            Set extraRows = new HashSet();
            rows = ((TransactionImpl) currentTransaction()).getDriver()
                .select(selector, extraRows);
            if (!rows.isEmpty()) {
                Row newFields = (Row) rows.iterator().next();
                // Determine which fields to copy
                Iterator i = dfg.getColumns().iterator();
                while (i.hasNext()) {
                    Column c = (Column) i.next();
                    row.setValue(c, newFields.getValue(c));
                }
            } else {
                throw new JDODataStoreException(I18N.msg("E_row_deleted"));
            }
        } catch (DriverException e) {

  
        ClassMapping mapping = handler.getClassMapping();
        Table table = mapping.getTable();


        // Look in datastore
        Row row = null;


        DataFetchGroup dfg = new DataFetchGroup(table.getColumns());
        Selector selector = new Selector
            (table,
             new SimpleCondition(table.getPrimaryKey(),

Examples of org.xorm.datastore.Row

Related Classes of org.xorm.datastore.Row