Steps to Invoke Azure Functions as SQL Functions
Shows the steps to invoke Azure remote functions as SQL functions in your database using HTTP trigger.
To invoke Azure Function as SQL functions, create a catalog of SQL wrapper functions that reference and call their respective cloud function through their API endpoints. Before you create this catalog, it is assumed here that you have created the necessary Azure functions to be referenced by this catalog.
- To access Azure functions you need to use Azure Service Principal with Autonomous Database. You must grant the Website Contributor role to the Azure Service Principal for the Azure function app under its Access control (IAM).See the following for more information:
- Create a catalog.
A catalog is a collection of wrapper functions that reference and call their respective cloud functions via their API endpoints.
Example to create a catalog for Azure functions.
BEGIN
DBMS_CLOUD_FUNCTION.CREATE_CATALOG
( credential_name => 'AZURE$PA', catalog_name => 'AZURE_DEMO_CATALOG', service_provider => 'AZURE', cloud_params => '{"subscription_id":"XXXXXXXXXXXXXXXXXXXXXXXX_example"}' ); END; /The
SUBSCRIPTION_ID
value in theCLOUD_PARAMS
is the subscription_id of the Azure function app.This creates the
AZURE_DEMO_CATALOG
catalog and catalogs all the functions of the providedSUBSCRIPTION_ID
.See CREATE_CATALOG Procedure for more information. You can query DBA_CLOUD_FUNCTION_CATALOG View and USER_CLOUD_FUNCTION_CATALOG View views to retrieve the list of all the catalogs in your database.
- You can list the functions in a catalog.
Following is the example to list Azure functions:
VAR function_list CLOB; BEGIN
DBMS_CLOUD_FUNCTION.LIST_FUNCTIONS
( credential_name => 'AZURE$PA', catalog_name => 'AZURE_DEMO_CATALOG', function_list => :function_list ); END; / SELECT JSON_QUERY (:function_list, '$' RETURNING VARCHAR2(32676) pretty) AS search_results FROM dual;See LIST_FUNCTIONS Procedure for more information.
- Run the
DBMS_CLOUD_FUNCTION.SYNC_FUNCTIONS
to create wrapper SQL functions. You can use one of the following methods to create the wrapper SQL functions in the catalog, that call their respective cloud functions:-
SYNC_FUNCTIONS:
SYNC_FUNCTIONS
is the quickest and simplest method, which automatically syncs (creates or deletes) wrapper functions in the catalog with the complete list of Azure functions. For example:
BEGIN
DBMS_CLOUD_FUNCTION.SYNC_FUNCTIONS
( catalog_name => 'AZURE_DEMO_CATALOG' ); END; /This creates a PL/SQL wrapper for adding new functions to the catalog and removing wrappers for functions that have been deleted from the catalog.
Note
When an Azure function is added, deleted, or disabled on the Azure function app, you must run theSYNC_FUNCTIONS
to update the corresponding PL/SQL wrappers in the catalog.Run the following query to verify the sync.
SELECT object_name FROM sys.all_objects WHERE owner='TEST_USER' AND object_type='FUNCTION';
Note
Keep a note of the current user in order to run this command.See SYNC_FUNCTIONS Procedure for more information.
- You can manually create a
SQL
Function in your catalog that calls its respective Azure function usingAZURE_DEMO_CATALOG
.
Example to create a function in the
AZURE_DEMO_CATALOG
catalog.BEGIN
DBMS_CLOUD_FUNCTION.CREATE_FUNCTION
( credential_name => 'AZURE$PA', catalog_name => 'AZURE_DEMO_CATALOG', function_name => 'azure_testfunc', function_id => 'function_id_path', input_args => :function_args ); END; /Note
The maximum length of the function name is limited to 100 characters.This creates the
AZURE_TESTFUNC
function in theAZURE_DEMO_CATALOG
catalog.The
AZURE_TESTFUNC
function in the catalog is a reference to the respective Azure function whose subscription is referenced by theFUNCTION_ID
parameter. Invoking the function in the catalog along with its arguments runs the corresponding Azure function and provides the output returned by the function.You can query DBA_CLOUD_FUNCTION View and USER_CLOUD_FUNCTION View views to retrieve the list of all the functions in your database.
See CREATE_FUNCTION Procedure for more information.
See Azure Functions HTTP trigger for more information.
-
- After the function is created you can
DESCRIBE
and invoke it.DESC AZURE_TESTFUNC
SELECT AZURE_TESTFUNC(NULL) FROM dual;
This invokes the
AZURE_TESTFUNC
function by calling the function reference/subscriptions/44496e556-8ssp-4262-b389-0f15f685c879/resources/ADBStest/providers/Microsoft.Web/sites/AZUREADBS/functions/HttpTrigger_example
in theAZURE_DEMO_CATALOG
catalog. - You can drop an existing function using
DROP_FUNCTION
procedure. For example:EXEC DBMS_CLOUD_FUNCTION.DROP_FUNCTION (CATALOG_NAME => 'AZURE_DEMO_CATALOG', FUNCTION_NAME => 'AZURE_TESTFUNC');
This drops the
AZURE_TESTFUNC
function from theAZURE_DEMO_CATALOG
catalog.See DROP_FUNCTION Procedure for more information.
- You can drop an existing catalog using
DROP_CATALOG
procedure. For example:BEGIN
DBMS_CLOUD_FUNCTION.DROP_CATALOG
( catalog_name => 'AZURE_DEMO_CATALOG' ); END; /This drops the
AZURE_DEMO_CATALOG
from your database.See DROP_CATALOG Procedure for more information.
Parent topic: Invoke User Defined Functions