Column Names and Quotes in Oracle. I have an existing table with all column nam

You can use JPA annotations in your XSD files to define tables and column names, as well as other attributes that require specific parameters or as in your Oracle database to create schemas, tables that are case sensitive.
Check out: forum.appian.com/.../Defining_a_Complex_Data_Type

I am very much familiar with the documentation you are referring to. The issue is that in my JPA annotations I have used all Capital Letters. Yet, the DDL generated has all Lower case letter AND quotes around each column name. The quotes is triggering case sensitivity and making Appian think the table does not exist. This is specific to Oracle

Which version of Appian is this?

I have tried in all versions 6.2, 7.2 and 7.3, with same results

Are you using the @Column(name="") and @Table(name="") annotations and place the exact name (case sensitive) inside this annotation? Appian will correctly read and maintain that name when searching for existing tables.

<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema
targetNamespace="appian.expressnet.redstone.gov/.../"
xmlns:types="appian.mms.vsak.com/.../" xmlns:xsd="www.w3.org/.../XMLSchema">
<xsd:complexType name="EXPRESS_NET_Users">
<xsd:annotation>
<xsd:appinfo source="appian.jpa">
           @Table(name="USERS")
</xsd:appinfo>
<xsd:documentation><![CDATA[Express Net Users]]></xsd:documentation>
</xsd:annotation>
<xsd:sequence>
<xsd:element name="UserName" type="xsd:string">
<xsd:annotation>
<xsd:appinfo source="appian.jpa">
@Id
@Column(name="ID", columnDefinition="varchar(40)")
</xsd:appinfo>
</xsd:annotation>
</xsd:element>
          
           <xsd:element name="FirstName" nillable="true" type="xsd:string">
<xsd:annotation>
<xsd:appinfo source="appian.jpa">

@Column(name="FIRST_NAME", columnDefinition="varchar(40)")
</xsd:appinfo>
                     <xsd:documentation>First Name of the User</xsd:documentation>
</xsd:annotation>
</xsd:element>
          
           <xsd:element name="LastName" nillable="true" type="xsd:string">
<xsd:annotation>
<xsd:appinfo source="appian.jpa">

@Column(name="LAST_NAME", columnDefinition="varchar(40)")
</xsd:appinfo>
                     <xsd:documentation>Last Name of the User</xsd:documentation>
</xsd:annotation>
</xsd:element>
          
</xsd:sequence>
</xsd:complexType>
</xsd:schema>

and the DDL generated is
/*
Data Store: EXPRESS_NET_USERS
Created: 2013-12-13T19:34:29.846Z
By: venkat.sakruti
Appian Version: 6.2.0.0
Target Database: Oracle Oracle Database 11g Release 11.1.0.0.0 - Production
Database Driver: Oracle JDBC driver 10.2.0.2.0
*/

/* UPDATE DDL */
create table "users" (
"id" varchar(40) not null,
"first_name" varchar(40),
"last_name" varchar(40),
primary key ("id")
);

/* DROP AND CREATE DDL */
/* WARNING: The DDL commented out below will drop and re-create all tables.
drop table "users" cascade constraints;

create table "users" (
"id" varchar(40) not null,
"first_name" varchar(40),
"last_name" varchar(40),
primary key ("id")
);
*/

You could try creating a synonym at the database level for this table (this means you won't have to use the schema annotation).
docs.oracle.com/.../statements_7001.htm

I don't have a DBA access to the Database. Datasource is configured and provided with existing tables. That it, we have to use existing schema and no changes are allowed in schema.

Also synonym will not solve the column name problem. That will solve only the table name problem