Dear User,
the DFB website database does not contain every match played by every team that exists in the database. In this respect, the outcome of any comparisons made between two teams will also only be based on the matches included in the database.
Furthermore, the data from the different leagues and competitions vary in depth. For example, every match played by the German national team since 1908 can be found in the database, along with the result and line-ups of both sides. Every DFB Cup match since the competition's founding in 1935 is also included - initially just with the results, and then from 1979/80 with each team's line-up as well.
The DFB online editorial team will be constantly expanding the database in the next few years, populating it with, for example, all the matches played by Germany's men's and women's youth teams.
In short, you can find an overview of the current status of the DFB data centre here.