CLOB Data Type

Description

A character large object containing single-byte or multibyte characters. Both fixed-width and variable-width character sets are supported, both using the database character set. (Oracle SQL Language Reference CLOB Data Type).

CLOB Data Type is not supported in Snowflake. VARCHAR is used instead.

Sample Source Patterns

CLOB in Create Table

Oracle

Query

IN -> Oracle_01.sql

CREATE TABLE clobtable ( clob_column CLOB, empty_column CLOB );

INSERT INTO clobtable VALUES ( 'THIS IS A TEST', EMPTY_CLOB() );

Snowflake

Query

OUT -> Oracle_01.sql

CREATE OR REPLACE TABLE clobtable ( clob_column VARCHAR,
empty_column VARCHAR
)
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"oracle"}}'
;

INSERT INTO clobtable
VALUES ( 'THIS IS A TEST', TO_VARCHAR(' - '));

Retrieving Data

Oracle

Query

IN -> Oracle_02.sql

SELECT * FROM clobtable;

Result

CLOB_COLUMN   |EMPTY_COLUMN|
--------------+------------+
THIS IS A TEST|            |

Snowflake

Query

OUT -> Oracle_02.sql

SELECT * FROM
clobtable;

Result

CLOB_COLUMN   |EMPTY_COLUMN|
--------------+------------+
THIS IS A TEST| -          |

Known Issues

1. The difference in max length CLOB (Oracle) and VARCHAR (Snowflake)

An Oracle CLOB column maximum size is (4 gigabytes - 1) * (database block size), but Snowflake VARCHAR is limited to 16MB.

2. Empty value with EMPTY_CLOB

Initializing a column using EMPTY_CLOB() will return an empty LOB locator. While in Snowflake after translation the column will return a string with ' - '.

3. No access to the DBMS_LOB built-in package

Since LOB data types are not supported in Snowflake there is not an equivalent for the DBMS_LOB functions and there are no implemented workarounds yet.