Create Table

In this section you could find information about TABLES, their syntax and current convertions.

1. Description

In Oracle, the CREATE TABLE statement is used to create one of the following types of tables: a relational table which is the basic structure to hold user data, or an object table which is a table that uses an object type for a column definition. (Oracle documentation)

Oracle syntax

CREATE [ { GLOBAL | PRIVATE } TEMPORARY | SHARDED | DUPLICATED | [ IMMUTABLE ] BLOCKCHAIN 
  | IMMUTABLE  ] 
   TABLE
  [ schema. ] table
  [ SHARING = { METADATA | DATA | EXTENDED DATA | NONE } ]
  { relational_table | object_table | XMLType_table }
  [ MEMOPTIMIZE FOR READ ]
  [ MEMOPTIMIZE FOR WRITE ]
  [ PARENT [ schema. ] table ] ;

Snowflake Syntax

CREATE [ OR REPLACE ]
    [ { [ { LOCAL | GLOBAL } ] TEMP | TEMPORARY | VOLATILE | TRANSIENT } ]
  TABLE [ IF NOT EXISTS ] <table_name> (
    -- Column definition
    <col_name> <col_type>
      [ inlineConstraint ]
      [ NOT NULL ]
      [ COLLATE '<collation_specification>' ]
      [
        {
          DEFAULT <expr>
          | { AUTOINCREMENT | IDENTITY }
            [
              {
                ( <start_num> , <step_num> )
                | START <num> INCREMENT <num>
              }
            ]
            [ { ORDER | NOORDER } ]
        }
      ]
      [ [ WITH ] MASKING POLICY <policy_name> [ USING ( <col_name> , <cond_col1> , ... ) ] ]
      [ [ WITH ] TAG ( <tag_name> = '<tag_value>' [ , <tag_name> = '<tag_value>' , ... ] ) ]
      [ COMMENT '<string_literal>' ]

    -- Additional column definitions
    [ , <col_name> <col_type> [ ... ] ]

    -- Out-of-line constraints
    [ , outoflineConstraint [ ... ] ]
  )
  [ CLUSTER BY ( <expr> [ , <expr> , ... ] ) ]
  [ ENABLE_SCHEMA_EVOLUTION = { TRUE | FALSE } ]
  [ STAGE_FILE_FORMAT = (
     { FORMAT_NAME = '<file_format_name>'
       | TYPE = { CSV | JSON | AVRO | ORC | PARQUET | XML } [ formatTypeOptions ]
     } ) ]
  [ STAGE_COPY_OPTIONS = ( copyOptions ) ]
  [ DATA_RETENTION_TIME_IN_DAYS = <integer> ]
  [ MAX_DATA_EXTENSION_TIME_IN_DAYS = <integer> ]
  [ CHANGE_TRACKING = { TRUE | FALSE } ]
  [ DEFAULT_DDL_COLLATION = '<collation_specification>' ]
  [ COPY GRANTS ]
  [ COMMENT = '<string_literal>' ]
  [ [ WITH ] ROW ACCESS POLICY <policy_name> ON ( <col_name> [ , <col_name> ... ] ) ]
  [ [ WITH ] TAG ( <tag_name> = '<tag_value>' [ , <tag_name> = '<tag_value>' , ... ] ) ]

For more Snowflake information review the following documentation.

2. Sample Source Patterns

2.1. Physical and Table Properties

Oracle

IN -> Oracle_01.sql
CREATE TABLE "MySchema"."BaseTable"
(
    BaseId NUMBER DEFAULT 10 NOT NULL ENABLE
) SEGMENT CREATION IMMEDIATE
  PCTFREE 0 PCTUSED 40 INITRANS 1 MAXTRANS 255
  COLUMN STORE COMPRESS FOR QUERY HIGH NO ROW LEVEL LOCKING LOGGING
  STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
  PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1
  BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)
  TABLESPACE "MyTableSpace"
  PARTITION BY LIST ("BaseId")
 (
    PARTITION "P20211231"  VALUES (20211231) SEGMENT CREATION DEFERRED
    PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255
    ROW STORE COMPRESS ADVANCED LOGGING
    STORAGE(
    BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)
    TABLESPACE "MyTableSpace" 
  )
  PARALLEL;

Snowflake

OUT -> Oracle_01.sql
CREATE OR REPLACE TABLE "MySchema"."BaseTable"
 (
     BaseId NUMBER(38, 18) /*** SSC-FDM-0006 - NUMBER TYPE COLUMN MAY NOT BEHAVE SIMILARLY IN SNOWFLAKE. ***/ DEFAULT 10 NOT NULL
 )
 COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"oracle"}}'
 ;

Table properties are removed because they are not required after the migration in Snowflake.

2.2. Constraints and Constraint States

The following constraints will be commented out:

  • CHECK Constraint

The USING INDEX constraint will be entirely removed from the output code during the conversion.

Oracle

IN -> Oracle_02.sql
CREATE TABLE "MySchema"."BaseTable"
(
    BaseId NUMBER DEFAULT 10 NOT NULL ENABLE NOVALIDATE,
    "COL1" NUMBER CHECK( "COL1" IS NOT NULL ),
	  CHECK( "COL1" IS NOT NULL ),
    CONSTRAINT "Constraint1BaseTable" PRIMARY KEY (BaseId)
        USING INDEX PCTFREE 10 INITRANS 2 MAXTRANS 255 COMPUTE STATISTICS
        STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
        PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1) ENABLE
);

Snowflake

OUT -> Oracle_02.sql
CREATE OR REPLACE TABLE "MySchema"."BaseTable"
	(
	    BaseId NUMBER(38, 18) /*** SSC-FDM-0006 - NUMBER TYPE COLUMN MAY NOT BEHAVE SIMILARLY IN SNOWFLAKE. ***/ DEFAULT 10 NOT NULL,
	    "COL1" NUMBER(38, 18) /*** SSC-FDM-0006 - NUMBER TYPE COLUMN MAY NOT BEHAVE SIMILARLY IN SNOWFLAKE. ***/ NOT NULL
-- 	                                                                                                                     --** SSC-FDM-0014 - CHECK STATEMENT NOT SUPPORTED **
-- 	                                                                                                                     CHECK( "COL1" IS NOT NULL )
 	                                                                                                                                                
-- 	                                                                                                                                                ,
--	--** SSC-FDM-0014 - CHECK STATEMENT NOT SUPPORTED **
--		  CHECK( "COL1" IS NOT NULL )
		                             ,
	    CONSTRAINT "Constraint1BaseTable" PRIMARY KEY (BaseId)
	)
	COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"oracle"}}'
	;

On the other hand, but in the same way, in case you have any constraint state after a NOT NULL constraint as follows:

  • RELY

  • NO RELY

  • RELY ENABLE

  • RELY DISABLE

  • VALIDATE

  • NOVALIDATE

These will also be commented out.

The ENABLE constraint state will be completely removed from the output code during the conversion process. In the case of the DISABLE state, it will also be removed concurrently with the NOT NULL constraint.

Oracle

IN -> Oracle_03.sql
CREATE TABLE Table1(
  col1 INT NOT NULL ENABLE,
  col2 INT NOT NULL DISABLE,
  col3 INT NOT NULL RELY
);

Snowflake

OUT -> Oracle_03.sql
CREATE OR REPLACE TABLE Table1 (
    col1 INT NOT NULL,
    col2 INT ,
    col3 INT NOT NULL /*** SSC-FDM-OR0006 - CONSTRAINT STATE RELY REMOVED FROM NOT NULL INLINE CONSTRAINT ***/
  )
  COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"oracle"}}'
  ;

2.3. Foreign Key

If there is a table with a NUMBER column with no precision nor scale, and another table with a NUMBER(*,0) column that references to the previously mentioned NUMBER column, we will comment out this foreign key.

Oracle

IN -> Oracle_04.sql
CREATE TABLE "MySchema"."MyTable"
(
    "COL1" NUMBER, 
    CONSTRAINT "PK" PRIMARY KEY ("COL1")
);

Snowflake

OUT -> Oracle_04.sql
CREATE OR REPLACE TABLE "MySchema"."MyTable"
    (
        "COL1" NUMBER(38, 18) /*** SSC-FDM-0006 - NUMBER TYPE COLUMN MAY NOT BEHAVE SIMILARLY IN SNOWFLAKE. ***/,
        CONSTRAINT "PK" PRIMARY KEY ("COL1")
    )
    COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"oracle"}}'
    ;

2.4. Virtual Column

Oracle

IN -> Oracle_05.sql
CREATE TABLE "MySchema"."MyTable"
(
    "COL1" NUMBER GENERATED ALWAYS AS (COL1 * COL2) VIRTUAL
);

Snowflake

OUT -> Oracle_05.sql
CREATE OR REPLACE TABLE "MySchema"."MyTable"
    (
        "COL1" NUMBER(38, 18) /*** SSC-FDM-0006 - NUMBER TYPE COLUMN MAY NOT BEHAVE SIMILARLY IN SNOWFLAKE. ***/ AS (COL1 * COL2)
    )
    COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"oracle"}}'
    ;

2.5. Identity Column

For identity columns, a sequence is created and assigned to the column.

Oracle

IN -> Oracle_06.sql
CREATE TABLE "MySchema"."BaseTable"
(
	"COL0" NUMBER GENERATED BY DEFAULT ON NULL 
		AS IDENTITY MINVALUE 1 MAXVALUE 9999999999999999999999999999 
		INCREMENT BY 1 
		START WITH 621 
		CACHE 20 
		NOORDER  NOCYCLE  NOT NULL ENABLE
);

Snowflake

OUT -> Oracle_06.sql
CREATE OR REPLACE SEQUENCE MySchema.BaseTable_COL0
	INCREMENT BY 1
	START WITH 621
COMMENT = 'FOR TABLE-COLUMN "MySchema.BaseTable".COL0';

CREATE OR REPLACE TABLE "MySchema"."BaseTable" (
	"COL0" NUMBER(38, 18) /*** SSC-FDM-0006 - NUMBER TYPE COLUMN MAY NOT BEHAVE SIMILARLY IN SNOWFLAKE. ***/ DEFAULT MySchema.BaseTable_COL0.NEXTVAL NOT NULL
)
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"oracle"}}'
;

2.6. CLOB and BLOB column declaration

Columns declared as CLOB or BLOB will be changed to VARCHAR.

Oracle

IN -> Oracle_07.sql
CREATE TABLE T
(
 Col1 BLOB DEFAULT EMPTY_BLOB(),
Col5 CLOB DEFAULT EMPTY_CLOB()
);

Snowflake

OUT -> Oracle_07.sql
CREATE OR REPLACE TABLE T
 (
  Col1 BINARY,
 Col5 VARCHAR
 )
 COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"oracle"}}'
 ;

2.7. Constraint Name

The constraint name is removed from the code because it is not applicable in Snowflake.

Oracle

IN -> Oracle_08.sql
CREATE TABLE "CustomSchema"."BaseTable"(
 "PROPERTY" VARCHAR2(64) CONSTRAINT "MICROSOFT_NN_PROPERTY" NOT NULL ENABLE
  );

Snowflake

OUT -> Oracle_08.sql
CREATE OR REPLACE TABLE "CustomSchema"."BaseTable" (
  "PROPERTY" VARCHAR(64) NOT NULL
   )
   COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"oracle"}}'
   ;

2.8. Default columns with times

The columns declared as Date types will be cast to match with the specific date type.

Oracle

IN -> Oracle_09.sql
CREATE TABLE TABLE1
(
"COL1" VARCHAR(50) DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE TABLE1
(
 COL0 TIMESTAMP(6) DEFAULT CURRENT_TIMESTAMP,
 COL1 TIMESTAMP(6) DEFAULT CURRENT_TIME,
 COL2 TIMESTAMP(6) WITH LOCAL TIME ZONE DEFAULT '1900-01-01 12:00:00',
 COL3 TIMESTAMP(6) WITH TIME ZONE DEFAULT '1900-01-01 12:00:00',
 COL4 TIMESTAMP(6) WITHOUT TIME ZONE DEFAULT '1900-01-01 12:00:00',
 COL5 TIMESTAMP(6) DEFAULT TO_TIMESTAMP('01/01/1900 12:00:00.000000 AM', 'MM/DD/YYYY HH:MI:SS.FF6 AM')
 );

Snowflake

OUT -> Oracle_09.sql
CREATE OR REPLACE TABLE TABLE1
 (
 "COL1" VARCHAR(50) DEFAULT TO_VARCHAR(CURRENT_TIMESTAMP(), 'YYYY-MM-DD HH:MI:SS')
 )
 COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"oracle"}}'
 ;

 --** SSC-FDM-0019 - SEMANTIC INFORMATION COULD NOT BE LOADED FOR TABLE1. CHECK IF THE NAME IS INVALID OR DUPLICATED. **
 CREATE OR REPLACE TABLE TABLE1
 (
  COL0 TIMESTAMP(6) DEFAULT CURRENT_TIMESTAMP() :: TIMESTAMP(6),
  COL1 TIMESTAMP(6) DEFAULT CURRENT_TIME() :: TIMESTAMP(6),
  COL2 TIMESTAMP_LTZ(6) DEFAULT '1900-01-01 12:00:00' :: TIMESTAMP_LTZ(6),
  COL3 TIMESTAMP_TZ(6) DEFAULT '1900-01-01 12:00:00' :: TIMESTAMP_TZ(6),
  COL4 TIMESTAMP(6) WITHOUT TIME ZONE DEFAULT '1900-01-01 12:00:00' :: TIMESTAMP(6) WITHOUT TIME ZONE,
  COL5 TIMESTAMP(6) DEFAULT TO_TIMESTAMP('01/01/1900 12:00:00.000000 AM', 'MM/DD/YYYY HH:MI:SS.FF6 AM') :: TIMESTAMP(6)
  )
 COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"oracle"}}'
 ;

2.9 Sharing and Memoptimize options

Some options in Oracle are not required in Snowflake. That is the case for the sharing and memoptimize options, they will be removed in the output code.

Oracle

IN -> Oracle_10.sql
CREATE TABLE table1 
    SHARING = METADATA (
     id NUMBER,
     name VARCHAR2(50),
     date DATE,
     CONSTRAINT pk_table PRIMARY KEY (id)
 ) MEMOPTIMIZE FOR READ;

Snowflake

OUT -> Oracle_10.sql
CREATE OR REPLACE TABLE table1 (
     id NUMBER(38, 18) /*** SSC-FDM-0006 - NUMBER TYPE COLUMN MAY NOT BEHAVE SIMILARLY IN SNOWFLAKE. ***/,
     name VARCHAR(50),
     date TIMESTAMP,
     CONSTRAINT pk_table PRIMARY KEY (id)
 )
 COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"oracle"}}'
 ;

3. Known Issues

  1. Some properties on the tables may be adapted to or commented on because the behavior in Snowflake is different.

4. Related EWIs

  1. SSC-EWI-0039: Sematic information could not be loaded.

  2. SSC-FDM-0006: Number type column may not behave similarly in Snowflake.

  3. SSC-FDM-0014: Check statement not supported.

  4. SC-FDM-OR0006: Constraint state removed from not null inline constraint.

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