Oracle - User-Defined Types¶

Description¶

User-defined data types use Oracle built-in data types and other user-defined data types as the building blocks of object types that model the structure and behavior of data in applications. The sections that follow describe the various categories of user-defined types. (Oracle SQL Language Reference User-defined Data Types)

Object Types¶

REF Data Types¶

An object identifier (represented by the keyword OID) uniquely identifies an object and enables you to reference the object from other objects or from relational tables. A data type category called REF represents such references. A REF data type is a container for an object identifier. REF values are pointers to objects. (Oracle SQL Language Reference REF Data Types)

Varrays¶

Nested Tables¶

Known Issues¶

1. DML usages for Object Types are not being transformed¶

As of now, only DDL definitions that use User-Defined Types are being transformed into Variant. This means that any Inserts, Updates or Deletes using User-defined Types are not being transformed and need to be manually transformed. There is no EWI for this but there is a work item to add this corresponding EWI.

2. Nested Table types are not being transformed¶

There is no known workaround for implementing Nested Tables, for this reason only recognition is offered for these elements.

3. Array types are not being transformed¶

For now these elements are only recognized. A known workaround exists and there is a work item to implement them.

4. REF Data Types are not supported, but there is no EWI related to them¶

They are not supported, and instead are reported as an unknown User-Defined Function, but there is a work item to add this corresponding EWI.

Related EWIs¶

No related EWIs.

REF Data Types¶

Description¶

An object identifier (represented by the keyword OID) uniquely identifies an object and enables you to reference the object from other objects or relational tables. A data type category called REF represents such references. A REF data type is a container for an object identifier. REF values are pointers to objects. (Oracle SQL Language Reference REF Data Types)

REF Data types are not supported in Snowflake, and there is no current workaround to implement a similar component.

As of now, they are currently being recognized as user-defined functions and “DANGLING” clauses are not being recognized. Finally, the OID clause in view is being removed, as there is no workaround for them.

CREATE VIEW generic_view AS
SELECT REF(type) AS ref_col, MAKE_REF(type, identifier_column) AS make_ref_col
FROM generic_table;

SELECT v.ref_col, v.make_ref_col
FROM generic_view v
WHERE v.ref_col IS NOT DANGLING AND v.make_ref_col IS NOT DANGLING

Sample Source Patterns¶

Types and Tables for References¶

Please consider the following types, tables, inserts and view. They will be used for the next pattern section.

Oracle¶

CREATE TYPE email_typ_demo AS OBJECT
	( email_id INTEGER
	, email VARCHAR2(30)
	);

CREATE TYPE customer_typ_demo AS OBJECT
    ( customer_id        INTEGER
    , cust_first_name    VARCHAR2(20)
    , cust_last_name     VARCHAR2(20)
    , email_id			 INTEGER
    ) ;

CREATE TABLE email_table_demo OF email_typ_demo;
CREATE TABLE customer_table_demo OF customer_typ_demo;

INSERT INTO customer_table_demo VALUES
(customer_typ_demo(1, 'First Name 1', 'Last Name 1', 1));

INSERT INTO customer_table_demo VALUES
(customer_typ_demo(2, 'First Name 2', 'Last Name 2', 2));

INSERT INTO email_table_demo VALUES
(email_typ_demo(1, 'abc@def.com'));

CREATE VIEW email_object_view OF email_typ_demo WITH OBJECT IDENTIFIER (email_id) AS
SELECT * FROM email_table_demo;

Selects and Views using REFs¶

Oracle¶

CREATE VIEW email_object_view OF email_typ_demo WITH OBJECT IDENTIFIER (email_id) AS
SELECT * FROM email_table_demo;

CREATE VIEW customer_view AS
SELECT REF(ctb) AS customer_reference
     , MAKE_REF(email_object_view, ctb.email_id) AS email_ref
FROM customer_table_demo ctb;

SELECT c.customer_reference.cust_first_name, c.email_ref.email
FROM customer_view c;

SELECT c.customer_reference.cust_first_name, c.email_ref.email
FROM customer_view c
WHERE c.email_ref IS NOT DANGLING;

Result with danglings¶

Result with no danglings¶

Snowflake¶

CREATE OR REPLACE VIEW email_object_view
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"oracle"}}'
AS
--** SSC-FDM-0001 - VIEWS SELECTING ALL COLUMNS FROM A SINGLE TABLE ARE NOT REQUIRED IN SNOWFLAKE AND MAY IMPACT PERFORMANCE. **
SELECT * FROM
     email_table_demo;

CREATE OR REPLACE VIEW customer_view
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"oracle"}}'
AS
SELECT REF(ctb) !!!RESOLVE EWI!!! /*** SSC-EWI-0073 - PENDING FUNCTIONAL EQUIVALENCE REVIEW FOR 'REF' NODE ***/!!! AS customer_reference
     , MAKE_REF(email_object_view, ctb.email_id) !!!RESOLVE EWI!!! /*** SSC-EWI-0073 - PENDING FUNCTIONAL EQUIVALENCE REVIEW FOR 'MAKE_REF' NODE ***/!!! AS email_ref
FROM
     customer_table_demo ctb;

     SELECT c.customer_reference.cust_first_name, c.email_ref.email
     FROM
     customer_view c;

     SELECT c.customer_reference.cust_first_name, c.email_ref.email
FROM
     customer_view c
WHERE c.email_ref;
-- ** SSC-EWI-0001 - UNRECOGNIZED TOKEN ON LINE '14' COLUMN '19' OF THE SOURCE CODE STARTING AT 'IS'. EXPECTED 'STATEMENT' GRAMMAR. LAST MATCHING TOKEN WAS ';' ON LINE '10' COLUMN '21'. FAILED TOKEN WAS 'IS' ON LINE '14' COLUMN '19'. CODE '94'. **
--                   IS NOT DANGLING

Known Issues¶

1. REF and MAKE_REF are not being recognized

Instead they are currently being marked as user-defined functions.

2. DANGLING clause is not being recognized

DANGLING clauses are causing parsing errors.

3. OID Clauses in view are not supported, but there is no EWI related to them¶

The OID clause is not supported by either the tool, nor Snowflake but there should be an EWI related to them.

Related EWIs¶

1. SSC-EWI-0001: Unrecognized token on the line of the source code.
2. SSC-EWI-0073: Pending Functional Equivalence Review.
3. SSC-FDM-0001: Views selecting all columns from a single table are not required in Snowflake.