How to filter table columns using a bridge-entity to query data in related tables

Data Service
1

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Backendless Version (3.x / 5.x, Online / Managed / Pro )

I’m looking for a way to filter the columns returned by a get rest-api query to a bridge-entity involved in two 1-many relationships with two tables? I’m able to get data but I’m over-querying data.

Client SDK (REST / Android / Objective-C / Swift / JS )

Application ID

Expected Behavior

Please describe the expected behavior of the issue, starting from the first action.

1.I’m looking for a way to filter the columns returned by a get rest-api query to a bridge-entity involved in two 1-many relationships with two tables? I’m able to get data but I’m over-querying data.
2. I want to specify data columns from related tables that should be returned by a query
3.

Actual Behavior

Please provide a description of what actually happens, working from the same starting point.
I’m getting all the data from all table columns
Be descriptive: “it doesn’t work” does not describe what the behavior actually is – instead, say “the request returns a 400 error with message XXX”. Copy and paste your logs, and include any URLs.

Reproducible Test Case

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If the issue is more complex or requires configuration, please provide a link to a project on Github that reproduces the issue.

2

Hi, @Admire_Mhlaba

You need to specify data relation column and the desired column from the related table in the GET request. As example:

property=reCountry.IndepYear&property=reCountry.LocalName

Response I got:

	{
		"___class": "AllColumns",
		"IndepYear": 1975,
		"objectId": "1",
		"LocalName": "Angola"
	}
3

REST Console
REST Console1482×883 59.8 KB

Good day, thank you for being kind enough to respond to my inquiry but where exactly do I specify these columns because after selecting the data relation column from the dropdown, I cannot enter anything else. The request URL is greyed out, meaning you cannot edit that either. Kindly help by indicating the place I need to specify columns I need returned using the attached image.

4

REST Console
REST Console1482×891 70.6 KB

Hi once again, I managed to add columns from data related columns as depicted in the image but the query does not filter data. I only requested BookId.BookName and BookId.BookPrice but I’m getting everything instead, kindly help me resolve this issue.

5

Try to write BookId.BookName as BookNameFromRelation at Columns/Properties
Also, you could change BookNameFromRelation for any other name for the property.

6

REST Console
REST Console1487×888 67.9 KB

Good day, thank you for your help and pointers. I discovered something quite peculiar, if I specify data relation column, and filter by Columns/Properties, it does not work, data is not filtered as needed but if I remove the data relation column then, filtering works and returns only data columns requested by the query or data specified by Columns/Properties.

7

Good day, thank you for your kind help, apparently specifying the data relation column is the reason why filtering was not working. I only specified Columns/Properties and it worked as it should just like you advised me to.

1 Like