doc-exports/docs/dws/tool/dws_16_0163.html

Renaming a Column

Using a Reserved Keyword As a Column Name

In GaussDB(DWS), reserved keywords must be enclosed in double quotation marks when they are used as column names. The following reserved keywords are supported: desc, checksum, operator, and size.

Input

create table `desc` (
    user char,
    checksum int,
    operator smallint,
    desc char,
    size bigint
);
drop table if exists `desc`;

Output

CREATE TABLE "public"."desc" (
  "user" CHAR(4),
  "checksum" INTEGER,
  "operator" SMALLINT,
  "desc" CHAR(4),
  "size" BIGINT
) WITH (ORIENTATION = ROW, COMPRESSION = NO) NOCOMPRESS DISTRIBUTE BY HASH ("user");

Using the Name of a Hidden Column of a System Catalog As a Column Name

If the defined column name is the same as that of a hidden column in a GaussDB(DWS) system catalog ( including xc_node_id and tableoid, cmax, xmax, cmin, xmin, ctid, tid.), you need to rename the column. To rename the column, add _new at the end. For example, change xc_node_id to xc_node_id_new.

Input

drop table if exists `renameFieldName`;
create table if not exists `renameFieldName`(
    xc_node_id int,
    tableoid char(3),
    cmax smallint,
    xmax bigint auto_increment,
    cmin varchar(10),
    xmin int,
    ctid int auto_increment,
    tid int
);
drop table if exists `renameFieldName`;

Output

DROP TABLE IF EXISTS "public"."renamefieldname";
CREATE TABLE IF NOT EXISTS "public"."renamefieldname" (
  "xc_node_id_new" INTEGER,
  "tableoid_new" CHAR(12),
  "cmax_new" SMALLINT,
  "xmax_new" BIGSERIAL,
  "cmin_new" VARCHAR(40),
  "xmin_new" INTEGER,
  "ctid_new" SERIAL,
  "tid_new" INTEGER
) WITH (ORIENTATION = ROW, COMPRESSION = NO) NOCOMPRESS DISTRIBUTE BY HASH ("xc_node_id_new");
DROP TABLE IF EXISTS "public"."renamefieldname";

Parent topic: Table (Optional Parameters and Operations)