Data not persisting into DB

Getting the following error when writing the data using write to data store entity smart service

There is a problem with task “Write RTRR roles AMU” in the process “RTRR Roles By AMU”. An error occurred while trying to write to the entity “RTRR_USER_ROLES” [id=6d16b390-92dc-4240-b4a0-b6f27e3156b3@9823, type=RTRR_USER_ROLES (id=2818)] (data store: RTRR Datastore). Details: java.lang.IllegalArgumentException: The list of records to be saved must not be null or empty: TypedValue[it=2819,v={}] Data: TypedValue[it=2819,v={}]

Followed the below steps

1)Created table with PK

2)created sequence for the PK value generation

CREATE TABLE "BPMSDATA"."RTRR_USER_ROLES"

( "ROLEID" NUMBER(18,0),

"OPERATINGDISTRICTDESC" VARCHAR2(40),

"AMUDESC" VARCHAR2(40),

"ROLE" VARCHAR2(40) ,

"USERNAME" VARCHAR2(40),

CONSTRAINT "RTRR_USER_ROLES_PK" PRIMARY KEY ("ROLEID"));

commit;

CREATE SEQUENCE "BPMSDATA"."RTRR_ROLES_AMU_SEQ " MINVALUE 1 MAXVALUE 9999999999999999999999999999 INCREMENT BY 1 START WITH 660 CACHE 20 NOORDER NOCYCLE ;

3)created CDT in Appian via XSD

<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:tns="urn:com:husky:types:appian:ewr" targetNamespace="urn:com:husky:types:appian:ewr">
  <xsd:complexType name="RTRR_USER_ROLES">
    <xsd:annotation>
      <xsd:appinfo source="appian.jpa">
  @Table(name="RTRR_USER_ROLES", schema="BPMSDATA")
   </xsd:appinfo>
      <xsd:documentation><![CDATA[BPMSDATA.EPM_PARF]]></xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="ROLEID" type="xsd:int">
        <xsd:annotation>
          <xsd:appinfo source="appian.jpa">@Id @SequenceGenerator(name="RTRR_ROLES_AMU_SEQ", sequenceName="RTRR_ROLES_AMU_SEQ") @GeneratedValue(strategy=GenerationType.SEQUENCE, generator="RTRR_ROLES_AMU_SEQ") @Column(name="ROLEID")</xsd:appinfo>
        </xsd:annotation>
      </xsd:element>
   <xsd:element name="OPERATINGDISTRICTDESC" type="xsd:string">
        <xsd:annotation>
          <xsd:appinfo source="appian.jpa">@Column(name="OPERATINGDISTRICTDESC", nullable=false)</xsd:appinfo>
        </xsd:annotation>
      </xsd:element>
      <xsd:element name="AMUDESC" type="xsd:string">
        <xsd:annotation>
          <xsd:appinfo source="appian.jpa">@Column(name="AMUDESC")</xsd:appinfo>
        </xsd:annotation>
      </xsd:element>
      <xsd:element name="ROLE" type="xsd:string">
        <xsd:annotation>
          <xsd:appinfo source="appian.jpa">@Column(name="ROLE")</xsd:appinfo>
        </xsd:annotation>
      </xsd:element>
   <xsd:element name="USERNAME" type="xsd:string">
        <xsd:annotation>
          <xsd:appinfo source="appian.jpa">@Column(name="USERNAME")</xsd:appinfo>
        </xsd:annotation>
      </xsd:element>    
    </xsd:sequence>
  </xsd:complexType>
</xsd:schema>

4)Published the cdt to datastore

5)Populating the values to CDT in process  model. logic to populate CDT

RTRREngineerAllUsers

load(
  local!rtrrAMUListOfUsers:ri!rtrrAMUListOfUsers ,
  append(ri!rtrrAMUListOfUsers,rule!EWR_PARF_USERS_FOR_AMUGROUPS(ri!selectedAMUCode_txt,local!rtrrAMUListOfUsers))
)

EWR_PARF_USERS_FOR_AMUGROUPS

with(local!engingeerGroup:
a!forEach(
                      
items: rule!RTRR_createGroupName(
                          ri!selectedAMUCode_txt,
                          cons!RTRR_SUFFIX_GROUP_NAME_ENGINEER
                        ),
                        expression: getgroupbyname(
                          fv!item
                        )
                      ),
                 local!RTRREngineerUsers: a!forEach(
                        items: local!engingeerGroup,
                        expression: {
                          if(
                            rule!isObjectNull(
                              fv!item
                            ),
                            {},                          
                           {                            
                             {"amuname":group(fv!item, "groupName"),"username":tostring(getdistinctusers(fv!item))}
                           }
                          )
                        }
                      ),
                      a!forEach(items:local!RTRREngineerUsers,
                      expression:{
                      rule!RTRRMAPCDTValues(userlist:fv!item.username,amuname:fv!item.amuname,rtrrAMUListOfUsers:ri!rtrrAMUListOfUsers)                     
                     
                     }
                      )
                 
                      )
                   

RTRRMAPCDTValues

append(ri!rtrrAMUListOfUsers,a!forEach(items:ri!userList,
expression:{cast('type!{urn:com:husky:types:appian:ewr}RTRR_USER_ROLES' ,
                            {"OPERATINGDISTRICTDESC":"","AMUDESC":ri!amuname,
                             "ROLE":cons!RTRR_SUFFIX_GROUP_NAME_ENGINEER,
                      "USERNAME":fv!item
                     /*concat(user(fv!Item,"firstName")," ",user(fv!Item,"lastName"))*/})}
                      )
                      )
      CDT data from PV               

 [ROLEID=, OPERATINGDISTRICTDESC=, AMUDESC=RTRR Abbey Engineer, ROLE=Engineer, USERNAME= ],
 [ROLEID=, OPERATINGDISTRICTDESC=, AMUDESC=RTRR Aberfeldy Engineer, ROLE=Engineer, USERNAME=]