Having trouble writing data to data store entity

Question

Hi all,

I am a beginner in Appian and I have come across a problem that I've debugged for an hour but can't find the solution to. I'm attempting to write data to a data store entity and I continue to get the following error:

Problem: An error occurred in executing an Activity Class.

Details: An error occurred while trying to write to the entity "vehicle_parts" [id=7241da9e-15f3-402f-ae6d-b0f08195974e@87648, type=VFM_Part (id=3724)] (data store: VFM DS CK). Details: java.lang.IllegalArgumentException: The record to be saved must not be null: TypedValue[it=3724,v=<null>] Data: TypedValue[it=3724,v=<null>]

Recommended Action: Examine the activity class to correct the error and then resume.

Priority of this problem: High Priority

Does anyone have any idea how to solve this? If it helps, I'm also having trouble finding the created table after I save and publish my data store with no issues.

mukeshm · Answer

@Table(name="VFM_Vehicle") @Id @GeneratedValue @Column(name="Id") @Column(name="REQUEST_ID") @Column(name="VIN", columnDefinition="VARCHAR(255) NOT NULL UNIQUE")

aloks0189 · Answer

ck0220 As i can find lot of useful information's related to your query, so here i would like to add few more points into the consideration: 
 
1. As you did not define @Table annotation, hence the table will be created by the name, same as CDT, for example: VFM_Part => vfmpart 
2. You can open Data Store and Download the DDL script, and check for Create Script is targeting to which table 
3. you can cross check the schema name under ..../suite/admin/ url > Integration > Data Sources 
4. As per my understanding, (if these all configurations are correct then) You are using Write to Data Store Entity Smart Service for storing the data into the corresponding table, so basically the above exception can also be thrown when the row which we are trying to store contains null as it's value (doesn't matter whether the Primary is Auto Generate or not, but value to be inserted must not be null) 
5. If you want to avoid the above case, where there are some changes of empty row to be coming from Process/Interface then try using Write to Multiple Data Store Entity Node, this will avoid empty rows to be inserted into the DB

I hope above points will you to debug the issue.

aloks0189 · Answer

Generally when we create a CDT, and if we don't define @Table Annotation in its XSD, then usually Appian will convert CDT name into small and removing special characters such as _ hence the table will be created by the name vfmpart while publishing the Data Store, that's why it's a best practice to define the Table name using Annotation in its XSD before publishing the Data Store. 
The reason behind by default name generation strategy is, Designer may or may not define the Annotation i.e. @Table in XSD file manually, then Appian must handle that scenario so that the Data Store should get published without any error, hence they define by default an alternate way.

Shivam Gupta · Answer

Two simple steps I suggest: 1- Check the process by monitoring it whether the data have some value as the statement clearly says "The record to be saved must not be null: ". If in some scenarios the values can be null check using XOR gateway and override write to DB if null values encounter. 2- if data is their than, you might have change something in cdt defination after publishing, Download the XSD of that cdt by clicking on setting button and selecting download XSD, and check the definition in you cdt are same as in CDT. If these are not same definitions change them accordingly and use the update version by XSD in setting menu. 
 
 IF not working at all, And u don't mind the previous data to loose, Their is a smart service as QueryDatabase use that and drop ur current table and publish the datastore again to create a new one. 
 remember when you didn't provide table name annotations appian automatically removes '_' from cdt name to create table name ex cdt name: EX_employee than table name would be EXemployee Hope these point will help you

Elly Meng · Answer

Super late reply but for anyone still running into this issue: you need to File > Save and Publish the process model before debugging it.