This scenario allows you to run a similarity search for specific documentation content based on a user query. Once documentation chunks are retrieved, they are concatenated and a prompt is generated to ask an LLM to answer the user question using retrieved chunks.

1. Start SQL*Plus and connect to Oracle Database as a local test user.
   1. Log in to SQL*Plus as the sys user, connecting as sysdba:

      conn sys/password AS sysdba

      SET SERVEROUTPUT ON;
      SET ECHO ON;
      SET LONG 100000;

   2. Create a local test user (vector) and grant necessary privileges:

      DROP USER vector cascade;

      CREATE USER vector identified by <my vector password>

      GRANT DB_DEVELOPER_ROLE, CREATE CREDENTIAL TO vector;

   3. Set the proxy if one exists:

      EXEC UTL_HTTP.SET_PROXY('<my proxy full name>:<my proxy port>');

   4. Grant connect privilege for a host using the DBMS_NETWORK_ACL_ADMIN procedure. This example uses * to allow any host. However, you can explicitly specify each host that you want to connect to.

      BEGIN
        DBMS_NETWORK_ACL_ADMIN.APPEND_HOST_ACE(
          host => '*',
          ace => xs$ace_type(privilege_list => xs$name_list('connect'),
                             principal_name => 'VECTOR',
                             principal_type => xs_acl.ptype_db));
      END;
      /

   5. Connect to Oracle Database as the test user.

      conn docuser/password;

2. Create a credential for Oracle Cloud Infrastructure Generative AI:

   1. Run DBMS_VECTOR_CHAIN.CREATE_CREDENTIAL to create and store an OCI credential (OCI_CRED).

      OCIGenAI requires the following parameters:

      { 
      "user_ocid"       : "<user ocid>",
      "tenancy_ocid"    : "<tenancy ocid>",
      "compartment_ocid": "<compartment ocid>",
      "private_key"     : "<private key>",
      "fingerprint"     : "<fingerprint>" 
      }

      Note:

      The generated private key may appear as:

      -----BEGIN RSA PRIVATE KEY-----
      <private key string>
      -----END RSA PRIVATE KEY-----

      You pass the <private key string> value (excluding the BEGIN and END lines), either as a single line or as multiple lines.

      BEGIN
        DBMS_VECTOR_CHAIN.DROP_CREDENTIAL(credential_name => 'OCI_CRED');
      EXCEPTION
        WHEN OTHERS THEN NULL;
      END;
      /

      DECLARE
        jo json_object_t;
      BEGIN
        jo := json_object_t();
        jo.put('user_ocid', '<user ocid>');
        jo.put('tenancy_ocid', '<tenancy ocid>');
        jo.put('compartment_ocid', '<compartment ocid>');
        jo.put('private_key', '<private key>');
        jo.put('fingerprint', '<fingerprint>');
        DBMS_VECTOR_CHAIN.CREATE_CREDENTIAL(
          credential_name => 'OCID_CRED',
          params          => json(jo.to_string));
      END;
      /

   2. Check credential creation:

      col owner format a15
      col credential_name format a20
      col username format a20

      SELECT owner, credential_name, username
      FROM all_credentials
      ORDER BY owner, credential_name, username;

3. Generate a prompt using similarity search results:

   Note:

   For information about loading the ONNX format model into the database as doc_model, see Import ONNX Models into Oracle Database End-to-End Example.

   SET SERVEROUTPUT ON;
   
   VAR prompt CLOB;
   VAR user_question CLOB;
   VAR context CLOB;
   
   BEGIN
     -- initialize the concatenated string
     :context := '';
   
     -- read this question from the user
     :user_question := 'what are vector indexes?';
   
     -- cursor to fetch chunks relevant to the user's query
     FOR rec IN (SELECT EMBED_DATA
                 FROM doc_chunks
                 WHERE DOC_ID = 'Vector User Guide'
                 ORDER BY vector_distance(embed_vector, vector_embedding(
                     doc_model using :user_question as data), COSINE)
                 FETCH EXACT FIRST 10 ROWS ONLY)
     LOOP
       -- concatenate each value to the string
       :context := :context || rec.embed_data;
     END LOOP;
   
     -- concatenate strings and format it as an enhanced prompt to the LLM
     :prompt := 'Answer the following question using the supplied context 
                   assuming you are a subject matter expert. Question: '
                   || :user_question || ' Context: ' || :context;
   
     DBMS_OUTPUT.PUT_LINE('Generated prompt: ' || :prompt);
   END;
   /

4. Issue the GenAI call:

   Note:

   For a list of all supported REST endpoints, see Supported Third-Party Provider Operations and Endpoints.

   DECLARE
     input CLOB;
     params CLOB;
     output CLOB;
   BEGIN
     input := :prompt;
     params := '{
       "provider" : "ocigenai",
       "credential_name" : "OCI_CRED",
       "url" : "https://inference.generativeai.us-chicago-1.oci.
               oraclecloud.com/20231130/actions/generateText",
       "model" : "cohere.command"
     }';
   
     output := DBMS_VECTOR_CHAIN.UTL_TO_GENERATE_TEXT(input, json(params));
     DBMS_OUTPUT.PUT_LINE(output);
     IF output IS NOT NULL THEN
       DBMS_LOB.FREETEMPORARY(output);
     END IF;
   EXCEPTION
     WHEN OTHERS THEN
       DBMS_OUTPUT.PUT_LINE(SQLERRM);
       DBMS_OUTPUT.PUT_LINE(SQLCODE);
   END;
   /