This chapter applies for Metadata, Connections, Lookup Tables, Sequences, and Parameters.
There are some properties which are common for all of the mentioned graph elements.
They all can be internal or external (shared).
If they are internal, they are part of the graph. They are contained in the graph and you can see them when you look at the Source tab in the Graph Editor.
If they are external (shared), they are located outside the graph
in some external file (in the meta,
conn, lookup,
seq subfolders, or in the
project itself, by default).
If you look at the Source tab, you can only see a link to such external file. It is in that file these elements are described.
Let us suppose that you have multiple graphs that use the same data files or the same database tables or any other data resource. For each such graph you can have the same metadata, connection, lookup tables, sequences, or parameters. These can be defined either in each of these graphs separately, or all of the graphs can share them.
In addition to metadata, the same is valid for connections (database connections, JMS connections, and QuickBase connections), lookup tables, sequences, and parameters. Also connections, sequences and parameters can be internal and external (shared).
It is more convenient and simple to have one external (shared) definition for multiple graphs in one location, i.e. to have one external file (shared by all of these graphs) that is linked to these various graphs that use the same resources.
It would be very difficult if you worked with these shared elements across multiple graphs separately in case you wanted to make some changes to all of them. In such a case you should have to change the same characteristics in each of the graphs. As you can see, it is much better to be able to change the desired property in only one location - in an external (shared) definition file.
You can create external (shared) graph elements directly, or you can also export or externalize those internal.
On the other hand, if you want to give someone any of your graphs, you must give them not only the graph, but also all linked information. In this case, it is much simpler to have these elements contained in your graph.
You can create internal graph elements directly, or you can internalize those external (shared) elements after they have been linked to the graph.
CloverETL Designer helps you to solve this problem of when to have internal or external (shared) elements:
Linking External Graph Elements to the Graph
If you have some elements defined in some file or multiple files outside a graph, you can link them to it. You can see these links in the Source tab of the Graph Editor pane.
Internalizing External Graph Elements into the Graph
If you have some elements defined in some file or multiple files outside the graph but linked to the graph, you can internalize them. The files still exist, but new internal graph elements appear in the graph.
Externalizing Internal Graph Elements in the Graph
If you have some elements defined in the graph, you can externalize them. They will be converted to the files in corresponding subdirectories and only links to these files will appear in the graph instead of the original internal graph elements.
Exporting Internal Graph Elements outside the Graph
If you have some elements defined in the graph, you can export them. New files outside the graph will be created (non-linked to the graph) and the original internal graph elements will remain in the graph.