Orchestrating Data Sources

Updated on 2023-11-24 GMT+08:00

View PDF

A data API can contain multiple data sources. Therefore, an API request can call multiple data sources. For example, the query result of the first data source can be used as the parameter of the second data source.

MySQL is used as an example. Assume that the data API contains data source 1 and data source 2, user01 is the data table of data source 1, and user02 is the data table of data source 2. The structures of the two tables are as follows:

**Table 1** Table structures
Data Source	Table Name	Parameter
Data source 1	user01	id (int) name (varchar)
Data source 2	user02	user_id (int) user_age (int) user_sex (varchar)

The data source SQL statement is designed as follows:

For data source 1, query the ID of the data record whose name is zhang in table user01. Assume that the return object from data source 1 is default1.

select id from user01 where name='zhang';

For data source 2, go to table user02 and find the data record of user_age corresponding to the ID found in table user01. Assume that the return object from data source 2 is default2.

select user_age from user02 where user_id=${default1[0].id};

${default1[0].id} indicates the query result from data source 1. (default1 indicates the return object from data source 1, and id indicates the query field of data source 1.)

Assume that the data tables user01 and user02 contain the following data records:

user01		user02
id	name	user_id	user_age	user_sex
1	zhang	2	17	Female
2	li	3	18	Male
3	wang	1	18	Male

The following response is returned when the data API is called:

{
     "default1":[{
         "id":1
     }],
     "default2":[{
         "user_age":18
     }]
}

Parent topic: Developing Custom Data Backends

Previous topic: Calling a Stored Procedure

Next topic: Using Optional Parameters

Feedback

Was this page helpful?

Helpful Not helpful

Provide feedback

Thank you very much for your feedback. We will continue working to improve the documentation.See the reply and handling status in My Cloud VOC.

The system is busy. Please try again later.

Which of the following issues have you encountered?

Content is inconsistent with the product UI

Unclear descriptions

Lack of examples or code

Incorrect steps

Can't find what I need

Lack of best practices

Feedback (optional)

0/500

Select at least one type of issue, and enter your comments or suggestions.

Enter a maximum of 500 characters.

Submit Cancel

For any further questions, feel free to contact us through the chatbot.

Chatbot