Help Center/ Data Warehouse Service / SQL Syntax Reference/ SQL Syntax Reference (9.1.1.x)/ DDL Syntax/ ALTER FOREIGN TABLE (GDS Import and Export)
Updated on 2025-10-10 GMT+08:00
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ALTER FOREIGN TABLE (GDS Import and Export)

Function

Modifies a GDS foreign table.

Precautions

None

Syntax

  • Set the attributes of a foreign table. 
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    ALTER FOREIGN TABLE [ IF EXISTS ]  table_name
    OPTIONS ( {[ ADD | SET | DROP ] option ['value']}[, ... ]);
  • Set a new owner. 
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    ALTER FOREIGN TABLE [ IF EXISTS ] tablename
    OWNER TO new_owner;
  • Set the row-level access control switch for foreign tables (supported by cluster versions 9.1.0 and later). 
    ALTER FOREIGN TABLE [ IF EXISTS ] tablename
        ENABLE | DISABLE | FORCE | NO FORCE ROW LEVEL SECURITY

Parameter Description

Table 1 ALTER FOREIGN TABLE (for GDS import and export) parameters

Parameter

Description

Value Range

IF EXISTS

Sends a message instead of an error if the specified index does not exist.

-

table_name

Specifies the name of an existing foreign table to be modified.

Name of an existing foreign table.

option

Specifies the name of the option to be modified.

See Table 2 in CREATE FOREIGN TABLE for details.

value

Specifies the new value of option.

-

new_owner

Specifies the new owner of the foreign table.

A string that indicates a valid username.

Examples

Create a foreign table customer_ft to import data from GDS server 10.10.123.234 in TEXT format.

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DROP FOREIGN TABLE IF EXISTS customer_ft;
CREATE FOREIGN TABLE customer_ft
(
    c_customer_sk             integer               ,
    c_customer_id             char(16)              ,
    c_current_cdemo_sk        integer               ,
    c_current_hdemo_sk        integer               ,
    c_current_addr_sk         integer               ,
    c_first_shipto_date_sk    integer               ,
    c_first_sales_date_sk     integer               ,
    c_salutation              char(10)              ,
    c_first_name              char(20)              ,
    c_last_name               char(30)              ,
    c_preferred_cust_flag     char(1)               ,
    c_birth_day               integer               ,
    c_birth_month             integer               ,
    c_birth_year              integer                       ,
    c_birth_country           varchar(20)                   ,
    c_login                   char(13)                      ,
    c_email_address           char(50)                      ,
    c_last_review_date        char(10)
)
    SERVER gsmpp_server
    OPTIONS
(
    location 'gsfs://10.10.123.234:5000/customer1*.dat',
    FORMAT 'TEXT' ,
    DELIMITER '|',
    encoding 'utf8',
    mode 'Normal')READ ONLY;

Modify the customer_ft attribute of the foreign table. Delete the mode option.

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ALTER FOREIGN TABLE customer_ft options(drop mode);

Helpful Links

CREATE FOREIGN TABLE (for GDS Import and Export) and DROP FOREIGN TABLE

Parent Topic: DDL Syntax