2.1 Car-Racing Example, JSON Documents

The car-racing example has three kinds of documents: a team document, a driver document, and a race document.

A document supported by a duality view always includes, at its top (root) level, a document-identifier field, _id, which corresponds to (all of) the identifying columns of the root table that underlies the view. See Document-Identifier Field for Duality Views. (In the car-racing example the root table of each duality view has a single identifying column, which is a primary-key column.)

The following naming convention is followed in this documentation:

  • The document-identifier field (_id) of each kind of document (team, driver, or race) corresponds to the root-table identifying columns of the duality view that supports those documents. For example, field _id of a team document corresponds to identifying (primary-key) column team_id of table team, which is the root table underlying duality view team_dv.

  • Documents of one kind (e.g. team), supported by one duality view (e.g. team_dv) can include other fields named ...Id (e.g. driverId), which represent foreign-key references to identifying columns in tables underlying other duality views — columns that contain data that's shared. For example, in a team document, field driverId represents a foreign key that refers to the document-identifier field (_id) of a driver document.

Note:

Only the application-logic document content, or payload of each document, is shown here. That is, the documents shown here do not include the automatically generated and maintained, top-level field _metadata (whose value is an object with fields etag and asof). However, this document-handling field is always included in documents supported by a duality view. See Creating Duality Views for information about field _metadata.

Example 2-1 A Team Document

A team document includes information about the drivers on the team, in addition to information that's relevant to the team but not necessarily relevant to its drivers.

  • Top-level field _id uniquely identifies a team document. It is the document-identifier field. Column team_id of table team corresponds to this field; it is the table's primary key.

  • The team information that's not shared with driver documents is in field _id and top-level fields name and points.

  • The team information that's shared with driver documents is in fields driverId, name, and points, under field driver. The value of field driverId is that of the document-identifier field (_id) of a driver document. 

{"_id"    : 302,
 "name"   : "Ferrari",
 "points" : 300,
 "driver" : [ {"driverId" : 103,
               "name"     : "Charles Leclerc",
               "points"   : 192},
              {"driverId" : 104,
               "name"     : "Carlos Sainz Jr",
               "points"   : 118} ]}

Example 2-2 A Driver Document

A driver document includes identification of the driver's team and information about the races the driver has participated in, in addition to information that's relevant to the driver but not necessarily relevant to its team or races.

  • Top-level field _id uniquely identifies a driver document. It is the document-identifier field. Column driver_id of the driver table corresponds to this field; it is that table's primary key.

  • The driver information that's not shared with race or team documents is in fields _id, name, and points.

  • The driver information that's shared with race documents is in field race. The value of field raceId is that of the document-identifier field (_id) of a race document.

  • The driver information that's shared with a team document is in fields such as teamId, whose value is that of the document-identifier field (_id) of a team document.

Two alternative versions of a driver document are shown, with and without nested team and race information.

Driver document, with nested team and race information:

Field teamInfo contains the nested team information (fields teamId and name). Field raceInfo contains the nested race information (fields raceId and name). 

{"_id"      : 101,
 "name"     : "Max Verstappen",
 "points"   : 258,
 "teamInfo" : {"teamId" : 301, "name" : "Red Bull"},
 "race"     : [ {"driverRaceMapId" : 3,
                 "raceInfo"        : {"raceId" : 201,
                                      "name"   : "Bahrain Grand Prix"},
                 "finalPosition"   : 19},
                {"driverRaceMapId" : 11,
                 "raceInfo"        : {"raceId" : 202,
                                      "name"   : "Saudi Arabian Grand Prix"},
                 "finalPosition"   : 1} ]}

Driver document, without nested team and race information:

Fields teamId and team are not nested in a teamInfo object. Fields raceId and name are not nested in a raceInfo object. 

{"_id"      : 101,
 "name"     : "Max Verstappen",
 "points"   : 25,
 "teamId"   : 301,
 "team"     : "Red Bull",
 "race"     : [ {"driverRaceMapId" : 3,
                 "raceId"          : 201,
                 "name"            : "Bahrain Grand Prix",
                 "finalPosition"   : 19},
                {"driverRaceMapId" : 11,
                 "raceId"          : 202,
                 "name"            : "Saudi Arabian Grand Prix",
                 "finalPosition"   : 1} ]}

Example 2-3 A Car-Race Document

A race document includes, in its information about a particular race, information about the podium standings (first, second, and third place), and the results for each driver in the race. The podium standings include the driver and team names. The result for each driver includes the driver's name.

Both of these include driver and team names.

  • Top-level field _id uniquely identifies a race document. It is the document-identifier field. Column race_id of the race table corresponds to this field; it is that table's primary key.

  • The race information that's not shared with driver or team documents is in fields _id, name (top-level), laps, date, time, and position.

  • The race information that's shared with driver documents is in fields such as driverId, whose value is that of the document-identifier field (_id) of a driver document.

  • The race information that's shared with team documents is in field team (under winner, firstRunnerUp, and secondRunnerUp, which are under podium).

Two alternative versions of a race document are shown, with and without nested driver information.

Race document, with nested driver information:

{"_id"    : 201,
 "name"   : "Bahrain Grand Prix",
 "laps"   : 57,
 "date"   : "2022-03-20T00:00:00",
 "podium" : {"winner"         : {"name" : "Charles Leclerc",
                                 "team" : "Ferrari",
                                 "time" : "02:00:05.3476"},
             "firstRunnerUp"  : {"name" : "Carlos Sainz Jr",
                                 "team" : "Ferrari",
                                 "time" : "02:00:15.1356"},
             "secondRunnerUp" : {"name" : "Max Verstappen",
                                 "team" : "Red Bull",
                                 "time" : "02:01:01.9253"}},
 "result" : [ {"driverRaceMapId" : 3,
               "position"        : 1,
               "driverInfo"      : {"driverId" : 103,
                                    "name"     : "Charles Leclerc"},
              {"driverRaceMapId" : 4,
               "position"        : 2,
               "driverInfo"      : {"driverId" : 104,
                                    "name"     : "Carlos Sainz Jr"},
              {"driverRaceMapId" : 9,
               "position"        : 3,
               "driverInfo"      : {"driverId" : 101,
                                    "name"     : "Max Verstappen"},
              {"driverRaceMapId" : 10,
               "position"        : 4,
               "driverInfo"      : {"driverId" : 102,
                                    "name"     : "Sergio Perez"} ]}

Race document, without nested driver information:

{"_id"    : 201,
 "name"   : "Bahrain Grand Prix",
 "laps"   : 57,
 "date"   : "2022-03-20T00:00:00",
 "podium" : {"winner"         : {"name" : "Charles Leclerc",
                                 "team" : "Ferrari",
                                 "time" : "02:00:05.3476"},
             "firstRunnerUp"  : {"name" : "Carlos Sainz Jr",
                                 "team" : "Ferrari",
                                 "time" : "02:00:15.1356"},
             "secondRunnerUp" : {"name" : "Max Verstappen",
                                 "team" : "Red Bull",
                                 "time" : "02:01:01.9253"}},
 "result" : [ {"driverRaceMapId" : 3,
               "position"        : 1,
               "driverId"        : 103,
               "name"            : "Charles Leclerc"},
              {"driverRaceMapId" : 4,
               "position"        : 2,
               "driverId"        : 104,
               "name"            : "Carlos Sainz Jr"},
              {"driverRaceMapId" : 9,
               "position"        : 3,
               "driverId"        : 101,
               "name"            : "Max Verstappen"},
              {"driverRaceMapId" : 10,
               "position"        : 4,
               "driverId"        : 102,
               "name"            : "Sergio Perez"} ]}

Related Topics

Parent topic: Introduction To Car-Racing Duality Views Example