-- Create a new table or a temporary table
CREATE [TEMP] TABLE [IF NOT EXISTS] table_name(
   pk SERIAL PRIMARY KEY,
   c1 type(size) NOT NULL,
   c2 type(size) NULL,
   ...
);

-- Add a new column into a table
ALTER TABLE table_name ADD COLUMN new_column_name TYPE;

-- Drop a column in a table
ALTER TABLE table_name DROP COLUMN column_name;

-- Rename a column
ALTER TABLE table_name RENAME column_name TO new_column_name;

-- Set or remove a default value for a column
ALTER TABLE table_name ALTER COLUMN [SET DEFAULT value | DROP DEFAULT]

-- Add a primary key to a table
ALTER TABLE table_name ADD PRIMARY KEY (column,...);

-- Remove the primary key from a table
ALTER TABLE table_name 
DROP CONSTRAINT primary_key_constraint_name;

-- Rename a table
ALTER TABLE table_name RENAME TO new_table_name;

-- Drop a table and its dependent objects:
DROP TABLE [IF EXISTS] table_name CASCADE;