Beginning Database Design Solutions, 2nd Edition

22MongoDB Atlas in Python

This chapter's example uses Python to build a NoSQL document database in the cloud. It uses the MongoDB Atlas database to save and query the following data about assignments for East Los Angeles Space Academy graduates, as shown in Table 22.1.

TABLE 22.1: Graduate assignments

FIRSTNAME	LASTNAME	POSITION	RANK	SHIP
Joshua	Ash	Fuse Tender	6th Class	Frieda's Glory
Sally	Barker	Pilot		Scrat
Sally	Barker	Arms Master		Scrat
Bil	Cilantro	Cook's Mate		Scrat
Al	Farnsworth	Diplomat	Hall Monitor	Frieda's Glory
Al	Farnsworth	Interpreter		Frieda's Glory
Major	Major	Cook's Mate	Major	Athena Ascendant
Bud	Pickover	Captain	Captain	Athena Ascendant

The next few sections talk a bit about this data, the way document databases store information, and the MongoDB Atlas database that we'll use for this example. The rest of the chapter describes the example program.

NOT NORMAL BUT NOT ABNORMAL

If you remember the relational database normalization rules, then you know that the data in the preceding table is not normalized because some non-key fields do not depend on all the key fields. Here, the key fields are FirstName, LastName, and Position, because we need all three to identify a record. However, the fields Rank and Ship depend on FirstName and LastName but not on Position.

You can also see the problem by looking for anomalies. For example, if you change one of Sally Barker's Ship values, then her ship assignments will be inconsistent (an ...