Convert Text String to Embedding Using the Local REST Provider Ollama

Perform a text-to-embedding transformation by accessing open embedding models, using the local host REST endpoint provider Ollama.

Ollama is a free and open-source command-line interface tool that allows you to run open embedding models and LLMs locally and privately on your Linux, Windows, or macOS systems. You can access Ollama as a service using SQL and PL/SQL commands.

You can call embedding models, such as all-minilm, mxbai-embed-large, or nomic-embed-text to vectorize your data. Note that you must use the same embedding model on both the data to be indexed and the user’s input query. In this example, you can see how to vectorize a user’s input query on the fly.

Here, you can call the chainable utility function UTL_TO_EMBEDDING (note the singular “embedding”) from either the DBMS_VECTOR or the DBMS_VECTOR_CHAIN package, depending on your use case. This example uses the DBMS_VECTOR.UTL_TO_EMBEDDING API. UTL_TO_EMBEDDING directly returns a VECTOR type (not an array).

WARNING:

Certain features of the database may allow you to access services offered separately by third-parties, for example, through the use of JSON specifications that facilitate your access to REST APIs.

Your use of these features is solely at your own risk, and you are solely responsible for complying with any terms and conditions related to use of any such third-party services. Notwithstanding any other terms and conditions related to the third-party services, your use of such database features constitutes your acceptance of that risk and express exclusion of Oracle’s responsibility or liability for any damages resulting from such access.

To convert a user’s input text string “hello” to a query vector, by calling a local embedding model using Ollama:

  1. Connect to Oracle AI Database as a local user.

    1. Log in to SQL*Plus as the SYS user, connecting as SYSDBA:

      conn sys/password as sysdba
      CREATE TABLESPACE tbs1
DATAFILE 'tbs5.dbf' SIZE 20G AUTOEXTEND ON
EXTENT MANAGEMENT LOCAL
SEGMENT SPACE MANAGEMENT AUTO;
      SET ECHO ON
SET FEEDBACK 1
SET NUMWIDTH 10
SET LINESIZE 80
SET TRIMSPOOL ON
SET TAB OFF
SET PAGESIZE 10000
SET LONG 10000

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

      DROP USER docuser cascade;
      CREATE USER docuser identified by docuser DEFAULT TABLESPACE tbs1 quota unlimited on tbs1;
      GRANT DB_DEVELOPER_ROLE, create credential to docuser;

    3. Connect as the local user (docuser):

      CONN docuser/password

  2. Install Ollama and run an embedding model locally.

    1. Download and run the Ollama application from https://ollama.com/download.

      You can either install Ollama as a service that runs in the background or as a standalone binary with a manual install. For detailed installation-specific steps, see Quick Start in the Ollama Documentation.

      Note the following:

      • The Ollama server needs to be able to connect to the internet so that it can download the models. If you require a proxy server to access the internet, remember to set the appropriate environment variables before running the Ollama server. For example, to set for Linux:

        -- set a proxy if you require one

export https_proxy=<proxy-hostname>:<proxy-port>
export http_proxy=<proxy-hostname>:<proxy-port>
export no_proxy=localhost,127.0.0.1,.example.com
export ftp_proxy=<proxy-hostname>:<proxy-port>

      • If you are running Ollama and the database on different machines, then on the database machine, you must change the URL to refer to the host name or IP address that is running Ollama instead of the local host.

      • You may need to change your firewall settings on the machine that is running Ollama to allow the port through.

    2. If running Ollama as a standalone binary from a manual install, then start the server:

      ollama serve

    3. Run a model using the ollama pull <embedding_model_name> command.

      For example, to call the all-minilm model:

      ollama pull all-minilm

      For detailed information on this step, see Ollama Readme.

    4. Verify that Ollama is running locally by using a cURL command.

      For example:

      -- get embeddings

curl http://localhost:11434/api/embeddings -d '{
  "model" : "all-minilm",
  "prompt": "What is Oracle AI Vector Search?"}'

  3. Set the HTTP proxy server, if configured.

    EXEC UTL_HTTP.SET_PROXY('<proxy-hostname>:<proxy-port>');

  4. Grant connect privilege to docuser for allowing connection to the host, using the DBMS_NETWORK_ACL_ADMIN procedure.

    This example uses * to allow any host. However, you can explicitly specify the 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 => 'docuser',
                       principal_type => xs_acl.ptype_db));
END;
/

  5. Call UTL_TO_EMBEDDING.

    The Ollama service has a REST API endpoint for generating embedding. Specify the URL and other configuration parameters in a JSON object.

    var embed_ollama_params clob;
exec :embed_ollama_params := '{
     "provider": "ollama",
     "host"    : "local",
     "url"     : "http://localhost:11434/api/embeddings",
     "model"   : "all-minilm"
}';

select dbms_vector.utl_to_embedding('hello', json(:embed_ollama_params)) ollama_output from dual;

    You can replace the url and model with your own values, as required.

    Note: For a complete list of all supported REST endpoint URLs, see Supported Third-Party Provider Operations and Endpoints.

    An excerpt from the generated embedding output is as follows:

    OLLAMA_OUTPUT
--------------------------------------------------------------------------------
[-2.31221581E+000,-3.26045007E-001,2.48111725E-001,-1.65610778E+000,1.10871601E+
000,-1.78519666E-001,-2.44365096E+000,-3.32534742E+000,-1.3771069E+000,1.8842382
4E+000,1.26494539E+000,-2.05359578E+000,-1.78593469E+000,-3.16150457E-001,-5.362
42545E-001,6.42113638E+000,-2.36518741E+000,2.21405053E+000,6.52316332E-001,-7.8
1692028E-001,2.32031775E+000,5.31627655E-001,-5.02781868E-001,7.03743398E-001,5.
48391223E-001,-3.16579014E-001,5.28999329E+000,1.63369191E+000,1.34206653E-001,9
.54429448E-001,-1.94197679E+000,2.39797616E+000,3.5270077E-001,-1.6536833E+000,-
5.74707508E-001,1.60994816E+000,3.80332375E+000,-6.30351126E-001,-1.5865227E+000
,-2.48650503E+000,-1.42142653E+000,-2.79453158E+000,1.76355612E+000,-2.48690337E
-001,1.5521245E+000,-1.95240334E-001,1.42441893E+000,-3.57098508E+000,4.02083158
E+000,-2.38530707E+000,2.34579134E+000,-2.79158998E+000,-5.92314243E-001,-9.7153

OLLAMA_OUTPUT

--------------------------------------------------------------------------------
9557E-001,1.6514441E-002,1.03710043E+000,1.96799666E-001,-2.18394065E+000,-2.786
71598E+000,-1.1549623E+000,1.92903787E-001,7.72498465E+000,-1.63462329E+000,3.33
839393E+000,-7.17389703E-001,-3.99817854E-001,7.7395606E-001,6.43829286E-001,1.8
5182285E+000,2.95272923E+000,-8.72635692E-002,1.77895337E-001,-1.19716954E+000,9
.43063736E-001,1.51703429E+000,-7.93301344E-001,1.92319798E+000,3.33290434E+000,
-1.29852867E+000,2.02961493E+000,-4.35824203E+000,1.30186975E+000,-1.0979414E+00
0,-7.07521975E-001,-4.50183332E-001,3.77224755E+000,-2.49138021E+000,-1.12575901
E+000,1.15370192E-001,1.66767395E+000,3.52229095E+000,-3.78049397E+000,-6.171851
75E-001,1.71992481E+000,2.33226371E+000,-3.35983014E+000,-3.78417182E+000,3.8380
127E+000,2.59293962E+000,-1.33574629E+000,-1.76218402E+000,3.53816301E-001,-1.80
47899E+000,9.85167921E-001,1.93026745E+000,2.15959966E-001,9.94020045E-001,6.189

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