Assemble Document and Link to Database
The following assumes that you have a complete source document, or a series of source documents that you can assemble into a complete document. It also assumes that you have placed the appropriate 'merge fields' into the source documents/clauses you intend to use for this purpose.
A word about 'flow':
Note, in the above process, that Pathagoras assembles the document (Step 1) totally independent from the external data source(s). The fields from the source document are present, but they are linked at this stage to nothing. The link to the data source is made only after the document is fully assembled.
This arguably 'backwards' order of assembly allows for much faster document assembly. When Word loads a form that is perpetually linked to a database, it confirms the link and makes a connection. The process is fairly fast, but it requires your intervention, and is definitely noticeable. Now imagine that you want to assemble 5 documents into one, and each of those 5 documents contains a merge field that is perpetually connected to an external database. As the document is being assembled, you will be asked to confirm the link 5 times. The calls to the external database would dramatically slow down the assembly process.)
Further, when the document is completed and all merge fields properly populated with the appropriate data, you are encouraged to disconnect the document from the data source. That way, if you need to recall the document for editing, you will not have to wait for the data source to be reconnected. (And it make it easier to edit the document on a computer that is not connected to the data source.)
Exception: If you use DropDown Lists as your primary document assembly tool, and the documents you call are complete forms and there is no other to disconnect the form from its data source, you should consider leaving the form and data source perpetually connected.