SnowConvert AI - IBM DB2 Issues¶

Severity¶

Low

Description¶

This message is shown whenever SnowConvert AI detects multiple security label column options inside the same CREATE TABLE clause, the security label is translated to a row access policy clause and Snowflake does not support multiple row access policy declarations. Therefore, if more than one security labels are found they will be commented out with this EWI.

 CREATE TABLE T1
(
COL1 VARCHAR(10) COLUMN SECURED WITH securityLabel1,
COL2 VARCHAR(10) COLUMN SECURED WITH securityLabel2
);

CREATE TABLE T1
(
COL1 VARCHAR(10),
COL2 VARCHAR(10)
)
WITH ROW ACCESS POLICY securityLabel1 ON (
COL1
)
!!!RESOLVE EWI!!! /*** SSC-EWI-DB0001 - WITH ROW ACCESS POLICY CLAUSE DOES NOT SUPPORT MULTIPLE DECLARATION IN SNOWFLAKE ***/!!!
WITH ROW ACCESS POLICY securityLabel2 ON (
COL2
)
;

Recommendations¶

• Review your code and ensure that only one security label is inside the CREATE TABLE clause

• If you need more support, you can email us at snowconvert-support@snowflake.com

Severity¶

Medium

Description¶

DB2 temporal tables do not have a functional equivalent in Snowflake. When an application-period or system-period temporal table declaration is found in the CREATE TABLE columns, that column is commented out from the resulting script. The behavior of the SELECT statement will differ from Snowflake because temporal tables are not part of the Snowflake solution and this causes the result to be different if the Select statement is migrated partially, see the example below for more information about this.

 SELECT 
  ID,
  Start,
  END
FROM 
  timetable 
FOR system_time as of '2022-05-09-16.20.17.0';

 SELECT 
  ID,
  Start,
  END
FROM 
  timetable 
-- FOR system_time as of '2022-05-09-16.20.17.0';

CREATE TABLE TestTable (
COL1 DATE,
COL2 DATE,
PERIOD SYSTEM_TIME (COL1, COL2),
PERIOD BUSINESS_TIME (COL1, COL2)

SELECT
   *
FROM
   Table1
FOR SYSTEM_TIME AS of Value

CREATE TABLE TestTable (
COL1 DATE,
COL2 DATE,
!!!RESOLVE EWI!!! /*** SSC-EWI-DB0003 - PERIOD SPECIFICATION IS NOT SUPPORTED IN SNOWFLAKE. ***/!!!
PERIOD SYSTEM_TIME (COL1, COL2),
!!!RESOLVE EWI!!! /*** SSC-EWI-DB0003 - PERIOD SPECIFICATION IS NOT SUPPORTED IN SNOWFLAKE. ***/!!!
PERIOD BUSINESS_TIME (COL1, COL2)
)

SELECT
   *
FROM
Table1
!!!RESOLVE EWI!!! /*** SSC-EWI-DB0003 - PERIOD SPECIFICATION IS NOT SUPPORTED IN SNOWFLAKE. ***/!!!
FOR SYSTEM_TIME AS of Value

Recommendations¶

• Snowflake allows the storage of historical table data for up to 90 days, to know more about this see Understanding & Using Time Travel.

• If you need more support, you can email us at snowconvert-support@snowflake.com

Severity¶

Low

Description¶

This message is shown when an OUTER table reference is found in a FROM clause inside of a SELECT statement. This clause is used to include from subtables in the intermediate result table of the SELECT statement. Subtables are related to typed tables in the DB2 database, that are created with the OF clause of the CREATE TABLE statement, which is also not supported in Snowflake.

Select * from OUTER(ATable);
Select * from ONLY(ATable);

Select * from
!!!RESOLVE EWI!!! /*** SSC-EWI-DB0004 - OUTER TABLE REFERENCE IS NOT SUPPORTED IN SNOWFLAKE. ***/!!!
OUTER(ATable) AS AliasName;

Select * from
ATable;

Recommendations¶

• If you need more support, you can email us at snowconvert-support@snowflake.com

Severity¶

Medium

Description¶

This message is shown when it is found in a CREATE VIEW a node or clause that is related to the data manipulation of rows in a CREATE VIEW. Note that in DB2 you can insert or update rows directly from a VIEW meanwhile in Snowflake this is not supported, because of this, nodes or clauses related to this functionality are commented and an EWI is added.

CREATE VIEW TestTableId2 AS Select * from TestTableId1 WITH ROW MOVEMENT;

 CREATE VIEW TestTableId2
 COMMENT = '{ "origin": "sf_sc", "name": "snowconvert", "version": {  "major": 0,  "minor": 0,  "patch": "0" }, "attributes": {  "component": "db2",  "convertedOn": "09/02/2025",  "domain": "no-domain-provided" }}'
 AS Select * from
  TestTableId1
 !!!RESOLVE EWI!!! /*** SSC-EWI-DB0005 - MANIPULATION OF DATA IN VIEWS IS NOT SUPPORTED. ***/!!!
 WITH ROW MOVEMENT;

Recommendations¶

• If you need more support, you can email us at snowconvert-support@snowflake.com

Severity¶

Medium

Description¶

This message is shown when a DATA CHANGE TABLE REFERENCE is found in a FROM Clause. A DATA CHANGE TABLE REFERENCE specifies an intermediate table, which consists of the rows that are changed by an UPDATE, DELETE or INSERT statement included in the DATA CHANGE TABLE REFERENCE.

In Snowflake, this is not supported, since it can’t modify the rows and return a result set of table at the same time, hence the Select is commented.

 SELECT
   *
FROM
   OLD Table(UPDATE T1 SET NAME = 'Tony' where ID = 4)

 UPDATE (SELECT EMPNO, SALARY, COMM,
     AVG(SALARY) OVER (PARTITION BY WORKDEPT),
     AVG(COMM) OVER (PARTITION BY WORKDEPT)
     FROM EMPLOYEE E) AS E(EMPNO, SALARY, COMM, AVGSAL, AVGCOMM)
   SET (SALARY, COMM) = (AVGSAL, AVGCOMM)
   WHERE EMPNO = '000120';
   
 UPDATE TABLE5
INCLUDE (col1 INT, col2 Varchar(10))
SET Column1 = 1;

SELECT
   *
FROM
   !!!RESOLVE EWI!!! /*** SSC-EWI-DB0006 - INTERMEDIATE RESULT TABLE IS NOT SUPPORTED. ***/!!!
   OLD Table(UPDATE T1 SET NAME = 'Tony' where ID = 4)

UPDATE
       !!!RESOLVE EWI!!! /*** SSC-EWI-DB0006 - INTERMEDIATE RESULT TABLE IS NOT SUPPORTED. ***/!!!
 (SELECT EMPNO, SALARY, COMM,
       AVG(SALARY) OVER (PARTITION BY WORKDEPT),
       AVG(COMM) OVER (PARTITION BY WORKDEPT)
       FROM EMPLOYEE E) AS E(EMPNO, SALARY, COMM, AVGSAL, AVGCOMM)
       SET
       SALARY = AVGSAL,
       COMM = AVGCOMM
WHERE EMPNO = '000120';

UPDATE TABLE5
!!!RESOLVE EWI!!! /*** SSC-EWI-DB0006 - INTERMEDIATE RESULT TABLE IS NOT SUPPORTED. ***/!!!
INCLUDE (col1 INT, col2 Varchar(10))
SET Column1 = 1;

Severity¶

Medium

Description¶

Unlike DB2, Snowflake does not allow using SELECT query results as the target of an INSERT statement, requiring instead that data be inserted directly into tables or materialized views.

 INSERT INTO
   (SELECT * FROM SOMEOTHERTABLE)
VALUES
   (DEFAULT);

 INSERT INTO
!!!RESOLVE EWI!!! /*** SSC-EWI-DB0007 - QUERY AS INSERT TARGET NAME IS NOT SUPPORTED ***/!!!
   (SELECT * FROM SOMEOTHERTABLE)
VALUES
   (DEFAULT);

Recommendations¶

• If you need more support, you can email us at snowconvert-support@snowflake.com

Severity¶

Medium

Description¶

Snowflake does not support the use of select queries in the From clause of a Delete statement. If the Delete statement is migrated partially we get an incomplete statement as the From clause will be empty.

 DELETE FROM (
SELECT * FROM table1
)

DELETE FROM
!!!RESOLVE EWI!!! /*** SSC-EWI-DB0008 - DELETE FROM SELECT STATEMENT IS NOT SUPPORTED. ***/!!!
 (
SELECT * FROM table1
)

Recommendations¶

• If you need more support, you can email us at snowconvert-support@snowflake.com

Severity¶

Medium

Description¶

Snowflake does not support the use of cursors as part of the Delete statement and Update statement. If the statement is migrated partially, we will get rid of the where clause in which the cursor is forming part, making it dangerous to delete or update the whole table.

 DELETE FROM table1 
WHERE CURRENT OF cursor1

 UPDATE table1
     SET col1 = 1
     WHERE CURRENT OF cursor1

DELETE FROM
table1
WHERE
!!!RESOLVE EWI!!! /*** SSC-EWI-DB0009 - POSITIONED CURRENT OF IS NOT SUPPORTED. ***/!!! CURRENT OF cursor1

UPDATE TABLE1
SET Column1 = 1
WHERE
!!!RESOLVE EWI!!! /*** SSC-EWI-DB0009 - POSITIONED CURRENT OF IS NOT SUPPORTED. ***/!!!
 CURRENT OF cursor1;

Recommendations¶

• For additional support, contact SnowConvert support at snowconvert-support@snowflake.com.

Severity¶

Medium

Description¶

This message is displayed when specifying the attribute of a structured type that is being set (called an attribute assignment). A structured type can be a subtype that allows attributes to be inherited from a supertype.

Snowflake does not support these types of structures.

For more information, see the DB2 CREATE TYPE (structured) documentation.

 UPDATE CIRCLES
     SET C..CENTER..X = C..CENTER..Y,
       C..CENTER..Y = C..CENTER..X
     WHERE ID = 999;

UPDATE CIRCLES
     SET
          !!!RESOLVE EWI!!! /*** SSC-EWI-DB0010 - ATTRIBUTE NAME IS NOT SUPPORTED IN SNOWFLAKE ***/!!! C..CENTER..X =
          !!!RESOLVE EWI!!! /*** SSC-EWI-DB0010 - ATTRIBUTE NAME IS NOT SUPPORTED IN SNOWFLAKE ***/!!! C..CENTER..Y,
          !!!RESOLVE EWI!!! /*** SSC-EWI-DB0010 - ATTRIBUTE NAME IS NOT SUPPORTED IN SNOWFLAKE ***/!!!
       C..CENTER..Y =
                      !!!RESOLVE EWI!!! /*** SSC-EWI-DB0010 - ATTRIBUTE NAME IS NOT SUPPORTED IN SNOWFLAKE ***/!!! C..CENTER..X
     WHERE ID = 999

Recommendations¶

• If you need more support, you can email us at snowconvert-support@snowflake.com

Severity¶

Medium

Description¶

This message is displayed when the assignment clause contains an expression not supported by Snowflake

Cases¶

 UPDATE EMPLOYEE EU
    SET (EU.COM, EU.SALARY) = (SELECT ES.SALARY FROM EMPLOYEE ES WHERE ES.WORKDEPT = EU.WORKDEPT)
    WHERE EU.EMPNO = '000120';

UPDATE EMPLOYEE EU
    SET
        !!!RESOLVE EWI!!! /*** SSC-EWI-DB0011 - ASSIGNMENT CLAUSE TYPE IS NOT SUPPORTED IN SNOWFLAKE ***/!!!
 (EU.COM, EU.SALARY) = (SELECT ES.SALARY FROM
         EMPLOYEE ES WHERE ES.WORKDEPT = EU.WORKDEPT)
    WHERE EU.EMPNO = '000120';

Recommendations¶

• If you need more support, you can email us at snowconvert-support@snowflake.com

Severity¶

Medium

Description¶

Snowflake does not support the use of view name in the insert target name statement.

 CREATE VIEW VIEW1 AS SELECT * FROM T;
INSERT INTO VIEW1 (COL1, COL2) VALUES (NULL, DEFAULT);

 CREATE VIEW PUBLIC.VIEW1
AS SELECT * FROM
PUBLIC.T;

!!!RESOLVE EWI!!! /*** SSC-EWI-DB0012 - INVALID NAME AS INSERTION TARGET, USE OF VIEW NAME IS NOT SUPPORTED IN SNOWFLAKE ***/!!!
INSERT INTO VIEW1 (COL1, COL2) VALUES (NULL,DEFAULT);

Recommendations¶

• If you need more support, you can email us at snowconvert-support@snowflake.com

Severity¶

Medium

Description¶

Snowflake does not support the use of view name in the delete target name statement. For this reason, the result query could not be valid

 CREATE VIEW VIEW1 AS SELECT * FROM T;
DELETE FROM VIEW1

 CREATE VIEW PUBLIC.VIEW1
AS SELECT * FROM
PUBLIC.T;


DELETE FROM
!!!RESOLVE EWI!!! /*** SSC-EWI-DB0013 - INVALID NAME AS DELETE TARGET, USE OF VIEW NAME IS NOT SUPPORTED IN SNOWFLAKE ***/!!!
 VIEW1

Recommendations¶

• If you need more support, you can email us at snowconvert-support@snowflake.com

Severity¶

Medium

Description¶

Snowflake does not support the use of external tables in the Select statement. For this reason, the result query could not be valid

 SELECT
   *
FROM
   EXTERNAL SOMENAME AS T1 LIKE TABLE2 USING(COMPRESS NO)

SELECT
   *
FROM
   !!!RESOLVE EWI!!! /*** SSC-EWI-DB0014 - THE USE OF EXTERNAL TABLE REFERENCES IS NOT SUPPORTED IN SNOWFLAKE ***/!!!
   EXTERNAL SOMENAME AS T1 LIKE TABLE2 USING(COMPRESS NO)

Recommendations¶

• If you need more support, you can email us at snowconvert-support@snowflake.com

Severity¶

High

Description¶

This message is shown when SnowConvert AI detects a CREATE VIEW statement that uses the OF type clause. In DB2, typed views are created with the OF type MODE DB2SQL syntax and are based on structured types for object-relational modeling. Snowflake does not support typed views or structured types, so the view definition is marked with this EWI and marked as invalid.

CREATE VIEW testView
OF Rootview MODE DB2SQL(REF IS oidColumn USER GENERATED)
AS SELECT * FROM testTable;

!!!RESOLVE EWI!!! /*** SSC-EWI-DB0015 - CREATE VIEW OF TYPE IS NOT SUPPORTED ***/!!!
CREATE VIEW testView
OF Rootview MODE DB2SQL(REF IS oidColumn USER GENERATED)
AS SELECT * FROM testTable;

Recommendations¶

• Refactor the typed view into a standard view or materialized view that selects from the underlying table(s)

• If you need more support, you can email us at snowconvert-support@snowflake.com

Severity¶

High

Description¶

This message is shown when SnowConvert AI detects the UNNEST or TABLE function in a FROM clause. In DB2, these table functions expand arrays or collections into rows (optionally with WITH ORDINALITY for row numbering). Snowflake has different syntax and semantics for array unnesting—FLATTEN is the equivalent—so the DB2 UNNEST/TABLE usage is marked as not supported.

SELECT
   *
FROM
   UNNEST(arrray) WITH ORDINALITY

SELECT
   *
FROM
   !!!RESOLVE EWI!!! /*** SSC-EWI-DB0016 - UNNEST FUNCTION IS NOT SUPPORTED ***/!!!
   UNNEST(arrray) WITH ORDINALITY;

Recommendations¶

• Replace DB2 UNNEST or TABLE with Snowflake FLATTEN to expand arrays into rows. Use FLATTEN(input => array_column) with appropriate column references

• If you need more support, you can email us at snowconvert-support@snowflake.com

Severity¶

High

Description¶

This message is shown when SnowConvert AI detects a CREATE TABLE statement that uses the OF type or UNDER clause. In DB2, typed tables are defined with a structured type hierarchy (e.g., OF Student_t UNDER Person) and support inheritance. Snowflake does not support typed tables or structured types, so the table definition is marked with this EWI.

CREATE TABLE Student OF Student_t UNDER Person
INHERIT SELECT PRIVILEGES;

!!!RESOLVE EWI!!! /*** SSC-EWI-DB0017 - TYPED TABLES ARE NOT SUPPORTED ***/!!!
CREATE TABLE Student OF Student_t UNDER Person
INHERIT SELECT PRIVILEGES;

Recommendations¶

• Refactor typed tables into standard tables. Model the type hierarchy with separate tables and foreign keys if inheritance relationships need to be preserved

• If you need more support, you can email us at snowconvert-support@snowflake.com

Severity¶

High

Description¶

This message is shown when SnowConvert AI detects a CREATE TABLE statement that defines a staging table using the FOR clause (e.g., CREATE TABLE emp_summary_s FOR emp_summary PROPAGATE IMMEDIATE). In DB2, staging tables are used for materialized query table propagation. Snowflake does not support this construct, so the table definition is marked with this EWI.

CREATE TABLE emp_summary_s FOR emp_summary PROPAGATE IMMEDIATE;

!!!RESOLVE EWI!!! /*** SSC-EWI-DB0018 - STAGING TABLES ARE NOT SUPPORTED ***/!!!
CREATE TABLE emp_summary_s FOR emp_summary PROPAGATE IMMEDIATE;

Recommendations¶

• Use Snowflake streams and tasks, or materialized views with refresh logic, to achieve similar incremental propagation behavior

• If you need more support, you can email us at snowconvert-support@snowflake.com

Severity¶

Low

Description¶

This message is shown when SnowConvert AI detects an ANALYZE_TABLE table factor in a FROM clause. In DB2, ANALYZE_TABLE invokes external analytics (e.g., SAS routines) inline in a query. Snowflake does not support this DB2-specific analytics integration, so the table reference is marked with this EWI.

SELECT
   *
FROM v1 ANALYZE_TABLE(
   IMPLEMENTATION 'PROVIDER=SAS; ROUTINE_SOURCE_TABLE=ETLIN.SOURCE_TABLE; ROUTINE_SOURCE_NAME=SCORING_FUN3;')
ORDER BY 1;

SELECT
   *
FROM
   !!!RESOLVE EWI!!! /*** SSC-EWI-DB0019 - ANALYZE TABLE FACTOR IS NOT SUPPORTED ***/!!!
   v1 ANALYZE_TABLE(
   IMPLEMENTATION 'PROVIDER=SAS; ROUTINE_SOURCE_TABLE=ETLIN.SOURCE_TABLE; ROUTINE_SOURCE_NAME=SCORING_FUN3;')
ORDER BY 1;

Recommendations¶

• Implement the analytics logic in Snowflake using Snowpark (Python/Java), stored procedures, or external functions, and restructure the query accordingly

• If you need more support, you can email us at snowconvert-support@snowflake.com

Severity¶

High

Description¶

This message is shown when SnowConvert AI detects the DATA CAPTURE CHANGES (or DATA CAPTURE NONE) clause in a CREATE TABLE statement. In DB2, this clause controls whether changed data is captured for replication (e.g., Q Replication). Snowflake does not support this DB2-specific clause, so it is marked with this EWI.

CREATE TABLE TestTable
(
   COL1 INT
) DATA CAPTURE CHANGES;

CREATE TABLE TestTable
(
   COL1 INT
)
!!!RESOLVE EWI!!! /*** SSC-EWI-DB0020 - DATA CAPTURE IS NOT SUPPORTED ***/!!!
 DATA CAPTURE CHANGES
;

Recommendations¶

• For change data capture in Snowflake, use Streams to track changes on tables

• If you need more support, you can email us at snowconvert-support@snowflake.com

Severity¶

Low

Description¶

This message is shown when SnowConvert AI detects a CREATE TABLE ... AS statement with materialized query options such as DATA INITIALLY DEFERRED, REFRESH DEFERRED, MAINTAINED BY SYSTEM, or ENABLE QUERY OPTIMIZATION. In DB2, these options define a refreshable materialized query table. Snowflake materialized views use different syntax and semantics, so these options are marked with this EWI.

CREATE TABLE TRANSCNT (ACCTID, LOCID, YEAR, CNT) AS
  (SELECT ACCOUNTID, LOCATIONID, YEAR, COUNT(*)
     FROM TRANS
     GROUP BY ACCOUNTID, LOCATIONID, YEAR )
     DATA INITIALLY DEFERRED
     REFRESH DEFERRED
     MAINTAINED BY SYSTEM
     ENABLE QUERY OPTIMIZATION;

CREATE TABLE TRANSCNT (ACCTID, LOCID, YEAR, CNT) AS
  (SELECT ACCOUNTID, LOCATIONID, YEAR, COUNT(*)
     FROM TRANS
     GROUP BY ACCOUNTID, LOCATIONID, YEAR )
!!!RESOLVE EWI!!! /*** SSC-EWI-DB0021 - MATERIALIZED QUERY IS NOT SUPPORTED ***/!!!
     DATA INITIALLY DEFERRED
     REFRESH DEFERRED
     MAINTAINED BY SYSTEM
     ENABLE QUERY OPTIMIZATION
;

Recommendations¶

• Convert to a Snowflake materialized view if you need automatic refresh. Use CREATE MATERIALIZED VIEW with appropriate refresh settings

• If you need more support, you can email us at snowconvert-support@snowflake.com

Severity¶

High

Description¶

This message is shown when SnowConvert AI detects a WITH (CTE) query in which the main SELECT references a table using the ANALYZE_TABLE table factor. DB2 allows inline analytics (e.g., SAS routines) via ANALYZE_TABLE in such contexts. Snowflake does not support this, so the entire WITH query is marked with this EWI.

WITH sas_score_in (c1,c2) AS
  (SELECT c1,c2 FROM t1)
  SELECT *
    FROM sas_score_in ANALYZE_TABLE(
    IMPLEMENTATION 'PROVIDER=SAS; ROUTINE_SOURCE_TABLE=ETLIN.SOURCE_TABLE; ROUTINE_SOURCE_NAME=SCORING_FUN3;');

!!!RESOLVE EWI!!! /*** SSC-EWI-DB0022 - WITH SELECT ANALYZED TABLE IS NOT SUPPORTED ***/!!!
WITH sas_score_in (c1,c2) AS
  (SELECT c1,c2 FROM t1)
  SELECT *
    FROM sas_score_in ANALYZE_TABLE(
    IMPLEMENTATION 'PROVIDER=SAS; ROUTINE_SOURCE_TABLE=ETLIN.SOURCE_TABLE; ROUTINE_SOURCE_NAME=SCORING_FUN3;');

Recommendations¶

• Refactor the query to remove ANALYZE_TABLE. Implement the analytics logic in Snowflake using Snowpark, stored procedures, or external functions, then integrate results via a separate step or view

• If you need more support, you can email us at snowconvert-support@snowflake.com