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Data Definition Language

  • CREATE
  • ALTER
  • DROP

CREATE

CREATE TABLE [table name] ( [column definitions] ) [table parameters]

CREATE TABLE employees (
    id            INTEGER       PRIMARY KEY,
    first_name    VARCHAR(50)   not null,
    last_name     VARCHAR(75)   not null,
    mid_name      VARCHAR(50)   not null,
    dateofbirth   DATE          not null
);

ALTER

ALTER objecttype objectname parameters.

ALTER TABLE sink ADD bubbles INTEGER;
ALTER TABLE sink DROP COLUMN bubbles;

DROP

DROP objecttype objectname.

DROP TABLE employees;

TRUNCATE

  • The TRUNCATE statement is used to delete all data from a table. It's much faster than DELETE.
TRUNCATE TABLE table_name;