Help Center/ GaussDB(DWS)/ SQL Syntax Reference/ SQL Syntax Reference (9.1.0.x)/ DDL Syntax/ ALTER FOREIGN TABLE (GDS Import and Export)
Updated on 2025-07-22 GMT+08:00
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ALTER FOREIGN TABLE (GDS Import and Export)

Function

Modifies a 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 Parameter Description 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