Grant privileges for a particular database in PostgreSQL
database, postgresql, privileges, sql
Solution
Basic concept in Postgres
Roles are global objects that can access all databases in a db cluster - given the required privileges.
A cluster holds many databases, which hold many schemas. Schemas (even with the same name) in different DBs are unrelated. Granting privileges for a schema only applies to this particular schema in the current DB (the current DB at the time of granting).
Every database starts with a schema `public` by default. That's a convention, and many settings start with it. Other than that, the schema `public` is just a schema like any other.
Coming from MySQL, you may want to start with a single schema `public`, effectively ignoring the schema layer completely. I am using dozens of schema per database regularly. Schemas are a bit (but not completely) like directories in the file system.
Once you make use of multiple schemas, be sure to understand `search_path` setting:
- How does the search_path influence identifier resolution and the "current schema"
Default privileges
Per documentation on `GRANT`:
PostgreSQL grants default privileges on some types of objects to `PUBLIC`. No privileges are granted to `PUBLIC` by default on tables, columns, schemas or tablespaces. For other types, the default privileges granted to `PUBLIC` are as follows: `CONNECT` and `CREATE TEMP TABLE` for databases; `EXECUTE` privilege for functions; and `USAGE` privilege for languages.
All of these defaults can be changed with `ALTER DEFAULT PRIVILEGES`:
- Grant all on a specific schema in the db to a group role in PostgreSQL
Group role
Like @Craig commented, it's best to `GRANT` privileges to a group role and then make a specific user member of that role (`GRANT` the group role to the user role). This way it is simpler to deal out and revoke bundles of privileges needed for certain tasks.
A group role is just another role without login. Add a login to transform it into a user role. More:
- Why did PostgreSQL merge users and groups into roles?
Predefined roles
Update: Postgres 14 or later adds the new predefined roles (formally "default roles") `pg_read_all_data` and `pg_write_all_data` to simplify some of the below. See:
- Grant access to all tables of a database
Recipe
Say, we have a new database `mydb`, a group `mygrp`, and a user `myusr` ...
While connected to the database in question as superuser (`postgres` for instance):
REVOKE ALL ON DATABASE mydb FROM public; -- shut out the general public
GRANT CONNECT ON DATABASE mydb TO mygrp; -- since we revoked from public
GRANT USAGE ON SCHEMA public TO mygrp;
To assign "a user all privileges to all tables" like you wrote (I might be more restrictive):
GRANT ALL ON ALL TABLES IN SCHEMA public TO mygrp;
GRANT ALL ON ALL SEQUENCES IN SCHEMA public TO mygrp; -- don't forget those
To set default privileges for future objects, run for every role that creates objects in this schema:
ALTER DEFAULT PRIVILEGES FOR ROLE myusr IN SCHEMA public
GRANT ALL ON TABLES TO mygrp;
ALTER DEFAULT PRIVILEGES FOR ROLE myusr IN SCHEMA public
GRANT ALL ON SEQUENCES TO mygrp;
-- more roles?
Now, grant the group to the user:
GRANT mygrp TO myusr;
Related answer:
- PostgreSQL - DB user should only be allowed to call functions
Alternative (non-standard) setting
Coming from MySQL, and since you want to keep privileges on databases separated, you might like this non-standard setting `db_user_namespace`. Per documentation:
This parameter enables per-database user names. It is off by default.
Read the manual carefully. I don't use this setting. It does not void the above.
Problem
I'm moving from MySQL to PostgreSQL and have hit a wall with user privileges. I am used to assigning a user all privileges to all tables of a database with the following command: ``` # MySQL grant all privileges on mydatabase.* to 'myuser'@'localhost' identified by 'mypassword'; ``` It appears to me that the PostgreSQL 9.x solution involves assigning privileges to a "schema", but the effort required of me to figure out exactly what SQL to issue is proving excessive. I know that a few more hours of research will yield an answer, but I think everyone moving from MySQL to PostgreSQL could benefit from having at least one page on the web that provides a simple and complete recipe. This is the only command I have ever needed to issue for users. I'd rather not have to issue a command for every new table. I don't know what scenarios have to be handled differently in PostgreSQL, so I'll list some of the scenarios that I have typically had to handle in the past. Assume that we only mean to modify privileges to a single database that has already been created. (1a) Not all of the tables have been created yet, or (1b) the tables have already been created. (2a) The user has not yet been created, or (2b) the user has already been created. (3a) Privileges have not yet been assigned to the user, or (3b) privileges were previously assigned to the user. (4a) The user only needs to insert, update, select, and delete rows, or (4b) the user also needs to be able to create and delete tables. I have seen answers that grant all privileges to all databases, but that's not what I want here. Please, I am looking for a simple recipe, although I wouldn't mind an explanation as well. I don't want to grant rights to all users and all databases, as seems to be the conventional shortcut, because that approach compromises all databases when any one user is compromised. I host multiple database clients and assign each client a different login. It looks like I also need the `USAGE` privilege to get the increasing values of a `serial` column, but I have to grant it on some sort of sequence. My problem got more complex.