Table extension framework

Assume that we have table TableExtensionParent and we want to make extension table TableExtensionChild

1. At TableExtensionChild table Add new relation named TableExtensionParent, table TableExtensionParent. Add new field ForeigKey -> PrimaryKey based at newly created TableExtensionChild table

Reference field to the primary table will be added automatically and it should look like:


2. Create a unique index for the reference field that points back to TableExtensionParent .

3. Create methods at child table
insert

public void insert()
{
    if (0 != this.TableExtensionParent)
    {
        // only insert if the FK is valid
        super();
    }
}

update

public void update()
{
    if (0 != this.TableExtensionParent)
    {
        // only update if the FK is valid
        super();
    }
}

find

public static TableExtensionChild find(
    recId               _recId,
    boolean             _forUpdate          = false,
    ConcurrencyModel    _concurrencyModel   = ConcurrencyModel::Auto)
{
    TableExtensionChild tableExtensionChild;

    tableExtensionChild.selectForUpdate(_forUpdate);
    if (_forUpdate && _concurrencyModel != ConcurrencyModel::Auto)
    {
        tableExtensionChild.concurrencyModel(_concurrencyModel);
    }

    select firstonly tableExtensionChild where tableExtensionChild.RecId == _recId;

    return tableExtensionChild;
}

findByParent

public static TableExtensionChild findByTableExtensionParent(RecId _tableExtensionParentRecId, boolean _forUpdate = false)
{
    TableExtensionChild tableExtensionChild;

    tableExtensionChild.selectForUpdate(_forUpdate);

    if (_tableExtensionParentRecId != 0)
    {
        select firstonly * from tableExtensionChild
            where tableExtensionChild.TableExtensionParent == _tableExtensionParentRecId;
    }

    return tableExtensionChild;
}

4. Update parent table and create PackedExtensions field

5. Add a delete action from the parent table to the child table.

6. Create/Update methods at parent table

Method to get child table:

public TableExtensionChild tableExtensionChild()
{
    return this.SysExtensionSerializerMap::getExTensiontable(tableNum(TableExtensionChild));
}

Method to pack the child table on the parent table packed extensions:

public void packTableExtensionChild(TableExtensionChild _tableExtensionChild)
{
    _tableExtensionChild.TableExtensionParent = this.RecId;
    this.SysExtensionSerializerMap::packExtensionTable(_tableExtensionChild);
}

Method to add a child table data source, that you might use in future to modify Query

public static QueryBuildDataSource addDataSource(QueryBuildDataSource _parentDataSource, TableId _tableId, JoinMode _joinMode = JoinMode::InnerJoin)
{
    QueryBuildDataSource qbds;

    if (null == _parentDataSource || tableNum(TableExtensionParent) != _parentDataSource.table() || tableNum(TableExtensionChild) != _tableId)
    {
        throw error(error::wrongUseOfFunction(funcName()));
    }

    switch (_tableId)
    {
        case tableNum(TableExtensionChild):
            qbds = _parentDataSource.addDataSource(_tableId);
            qbds.addLink(fieldNum(TableExtensionParent, RecId), fieldNum(TableExtensionChild, TableExtensionParent));

            qbds.fetchMode(QueryFetchMode::One2One);
            qbds.joinMode(_joinMode);
            break;
    }

    return qbds;
}

Create/Update insert method:

public void insert()
{
    super();

    this.SysExtensionSerializerMap::postInsert();
}

Create/Update update method:

public void update()
{
    super();

    this.SysExtensionSerializerMap::postUpdate();
}

7. Integrate with the table extensions framework
Add parent table to SysExtensionSerializerMap map and child table to SysExtensionSerializerExtensionMap

8. Create simple form to test result
Please be aware that write method of parent datasource should be modified:

public void write()
{
    super();
    TableExtensionChild.SysExtensionSerializerExtensionMap::insertAfterBaseTable(TableExtensionParent);
}

write method of child table triggers first and as a result child record will not be saved as it's insert and update methods does not allow it without correct foreign key.

Download test table extension shared project

If you know russian language you can also watch more detailed video about extension framework:
https://www.youtube.com/watch?v=YrfHtAKRMbk

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