FireDAC Components for REST

Build 23.0.8804

Relational Model

The CData FireDAC Components for REST can be configured to create a relational model of the data, treating each XPath as an individual table containing a primary key and a foreign key that links to the parent document. This is particularly useful if you need to work with your data in existing BI, reporting, and ETL tools that expect a relational data model.

Joining Nested Arrays as Tables

With DataModel set to "Relational", any JOINs are controlled by the query. Any time you perform a JOIN query, the file or source will be queried once for each table included in the query.


Below is a sample query against the sample document in Raw Data, using a relational model based on the XPaths "/root/people", "/root/people/vehicles", and "/root/people/vehicles/maintenance".

Connecting String

Set the DataModel connection property to "Relational" and set the XPath connection property to "/root/people;/root/people/vehicles;/root/people/vehicles/maintenance;" to perform the following query and see the example result set.



The following query explicitly JOINs the people, vehicles, and maintenance tables.

  [people].[personal.age] AS age, 
  [people].[personal.gender] AS gender, 
  [people].[] AS first_name, 
  [people].[] AS last_name, 
  [vehicles].[] AS ins_company, 
  [vehicles].[insurance.policy_num] AS ins_policy_num, 
  [maintenance].[date] AS maint_date, 
  [maintenance].[desc] AS maint_desc
  [people].[_id] = [vehicles].[people_id]
  [vehicles].[_id] = [maintenance].[vehicles_id]


In the example query, each maintenance element is JOINed to its parent vehicle element, which is JOINed to its parent people element to produce a table with 8 rows (2 maintenance entries for each of 2 vehicles each for 2 people).

20MJohnDoeinternetcarHonda CivicABC Insurance123452017-07-17oil change
20MJohnDoeinternetcarHonda CivicABC Insurance123452018-01-03new tires
20MJohnDoeinternettruckDodge RamABC Insurance123452017-08-27new tires
20MJohnDoeinternettruckDodge RamABC Insurance123452018-01-08oil change
24FJaneRobertsphonecarToyota CamryCar Insurance987652017-05-11tires rotated
24FJaneRobertsphonecarToyota CamryCar Insurance987652017-11-03oil change
24FJaneRobertsphonecarHonda AccordCar Insurance987652017-10-07new air filter
24FJaneRobertsphonecarHonda AccordCar Insurance987652018-01-13new brakes

See Also

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Build 23.0.8804