PostgreSQL users, databases and table management, operation and authorization methods

/* Switch to database user */
su - postgres
/* Log in */
psql

bash-4.2$ psql
psql (9.3.17)
Type "help" for help.
postgres=> 

/* Log in to the specified database */
psql -U user -d dbname
/* List database */
\l
/* Switch database */
\c dbname

/* Create user */
CREATE ROLE rolename;
CREATE USER username WITH PASSWORD '*****';
/* Show all users */
\du
/* Modify user permissions */
ALTER ROLE username WITH privileges;
/* All permissions assigned to the user table */
GRANT ALL ON tablename TO user; 
/* All permissions assigned to the user database */
GRANT ALL PRIVILEGES ON DATABASE dbname TO dbuser;
/* Revoke user permissions */
REVOKE privileges ON tablename FROM user;
/* Revoke user permissions */

/* Create a database */
create database dbname; 
/* Delete the database */
drop database dbname; 

/* Add permission to increase the primary key itself */
grant all on sequence tablename_keyname_seq to webuser;
 /* Rename a table */
alter table [Table nameA] rename to [Table nameB]; 
/* Delete a table */
drop table [Table name]; 
/* Add fields in existing tables */
alter table [Table name] add column [Field name] [type]; 
/* Delete fields in the table */
alter table [Table name] drop column [Field name]; 
/* Rename a field */
alter table [Table name] rename column [Field nameA] to [Field nameB]; 
/* Set default value for a field */
alter table [Table name] alter column [Field name] set default [New default value];
/* Remove default value */
alter table [Table name] alter column [Field name] drop default; 
/* Insert data */
insert into Table name ([Field namem],[Field namen],......) values ([ListmValue of],[ListnValue of],......); 
/* Modify data */
update [Table name] set [目标Field name]=[Target value] where ...; 
/* Delete data */
delete from [Table name] where ...; 
/* Delete table */
delete from [Table name];
/* Query */
SELECT * FROM dbname WHERE ...;
/* Create table */
create table (
  [Field name1] [type1] primary key,
  [Field name2] [type2],
  ......,
  [Field namen] [Field namen] )

\q
quit

alter user test set default_transaction_read_only=on;
grant all on database crm_db to test;
grant select on all tables in schema public to test;   // What works is this sentence: To enter the crm_db operation, the db permission will be granted in which db environment

revoke all on database crm_prod_myl from test;
revoke select on all tables in schema public from test;