Querying the Data from Views

RE: Querying the Data from Views

Peter Lewis — Wed, 04 Aug 2021 20:09:23 GMT

Some additional context: Appian requires you to define a field as a PK in order to map it to a data store entity. It's also required for several other parts of Appian (e.g. as the source of a recordv type). However, a DB View doesn't have a concept of a PK field, so you often will need to construct a field in your DB view that is unique to act as the PK in Appian.

The error that you're seeing about "a_id" is Appian's attempt to automatically add a PK field for you. If you have a table, Appian on publish of the data store Appian can actually alter the table to add this as a PK. However, a database view wouldn't allow this (since it isn't a table), so that's why you're seeing this error.

RE: Querying the Data from Views

santhoshk0003 — Wed, 04 Aug 2021 04:57:45 GMT

Thank you salim, I got it

RE: Querying the Data from Views

salim.galfane — Tue, 03 Aug 2021 13:04:17 GMT

this means in the cdt, you did not mention which column is primary key. update the corresponding cdt and mark column id as primary key. You should then be able to publish the datastore

RE: Querying the Data from Views

santhoshk0003 — Tue, 03 Aug 2021 11:33:43 GMT

Thanks for replying salim in more info its showing

<<<

The data source schema does not match the type mappings: Missing column: a_id in Appian.losviewpractice (APNX-2-4056-000)

>>>

my column is named " id " actually not "a_id" like it shows in error message, thought you should know

RE: Querying the Data from Views

salim.galfane — Tue, 03 Aug 2021 11:31:28 GMT

You need to open the draft datastore and try to validate it. It will probably see an error, click on the more option to see details of the error, and write it back here.

RE: Querying the Data from Views

santhoshk0003 — Tue, 03 Aug 2021 11:16:55 GMT

yes stefan, I have created a view from two of my tables and then i tried to create a CDT from view, but even after selecting the check box that lets you to crate an Entity for the Data Type, Its not able to create an Entity. and is showing an Error that states

"""

Data Store Not Published

Data type created successfully. The entity was added to the selected data store, but one or more of the data entities does not map to the table structure in the selected data source. The data store has been saved as a draft. View Data Store

"""

i am unable to get it right please help me

RE: Querying the Data from Views

Stefan Helzle — Mon, 02 Aug 2021 09:01:54 GMT

More details please. What went wrong? Any error messages? Did you try to add the entity manually to the DS?

RE: Querying the Data from Views

santhoshk0003 — Mon, 02 Aug 2021 08:42:13 GMT

while i am creating CDT from a view the CDT is being created all good but the mapping to data store is not happening and i can't seem to find why? can you please help me??

RE: Querying the Data from Views

Ponnuchamy Arumugasamy — Mon, 18 May 2020 20:13:33 GMT

Thanks for your information. I will do it.

RE: Querying the Data from Views

Ponnuchamy Arumugasamy — Mon, 18 May 2020 20:10:39 GMT

Sure. I will do. Thank you.

RE: Querying the Data from Views

Mike Schmitt — Mon, 18 May 2020 19:06:08 GMT

Similar to how you query from a regular table, Views are also queried by creating a CDT and Data Store Entity mapping to the view. The one word of caution I would give you is to make sure you construct your View such that your primary key column is actually unique. If it's not a unique value, funny things will happen when you query on the view, relating to the count of items it contains.

RE: Querying the Data from Views

sujithap951 — Mon, 18 May 2020 17:32:20 GMT

Hi,

You can Create CDT for the view similar to how you create for a table and map it to the data store. Then you can query using a!queryEntity(). Querying is pretty much same how you can do with tables except write operations.

RE: Querying the Data from Views

Ponnuchamy Arumugasamy — Mon, 18 May 2020 16:22:59 GMT

Yeah. Thanks for your response.

Please refer to the structure of the tables that I gonna use to create a View using Join operation.

Student Table:

Pass_Request_Details Table:

Pass_Data View:

My question is how to query this data (from above mentioned View) and use it in our appian application like in Interface, Reports etc. Thanks for your help.

RE: Querying the Data from Views

Mike Schmitt — Mon, 18 May 2020 12:36:57 GMT

That sounds fine - do you have any particular question?