What are roles and privileges to give a user in order to perform CRUD(on Oracle 12) - oracle

Question

I'm creating a USER on Oracle 12 c database, using TOAD.
After creating the TABLESPACE, I'm creating the USER. I'm a little confusing about the many ROLES and PRIVILEGES that can be given to a USER.
What are the minimum/standard roles and privileges a user must be given in order to perform CRUD operation and being able to 'edit' the database (create or delete table, DROP the schema ecc) from TOAD?
Thank you

Answer 1

It depends on what operations are you going to perform. If you want to work only with tables in your own db schema, then the following privileges are usually enough to start:
grant create session to <your_user>;
grant create table to <your_user>;
You have the default rights to insert/update/delete/select tables which you own.
Tablespace quota:
alter user <your_user> quota unlimited on <your_tablespace_name>;
It's better to set the default tablespace for the user. In this case you can omit the tablespace name in a create table statement.
alter user <your_user> default tablespace <your_tablespace_name>;

Answer 2

A link to the documentation - Privileges
Grant the user the following privileges:
CREATE SESSION (in order to allow the user to connect to the database)
INSERT
UPDATE
DELETE
SELECT
Use the below command to grant privileges to the user (you need to login as SYS or SYSTEM or another user that has GRANT privilege):
GRANT CREATE SESSION, SELECT, UPDATE, DETETE, INSERT TO user_name

Answer 3

Here's a suggestion you might (or might not) want to follow.
As a privileged user (such as SYS), check tablespaces available in your database. I'm using 11g XE (Express Edition) which shows the following:
SQL> show user
USER is "SYS"
SQL> select tablespace_name from dba_tablespaces;
TABLESPACE_NAME
------------------------------
SYSTEM
SYSAUX
UNDOTBS1
TEMP --> temporary
USERS --> my data
Now, create a user:
SQL> create user mdp identified by pdm
2 default tablespace users
3 temporary tablespace temp
4 quota unlimited on users;
User created.
Quite a long time ago, there were two popular predefined roles named CONNECT and RESOURCE which were granted some of the most frequent privileges so people just loved to grant those roles to newly created users.
Nowadays, you shouldn't be doing that: grant only minimal set of privileges your user might need. The first one is CREATE SESSION; without it, your user won't even be able to establish a connection.
SQL> grant create session to mdp;
Grant succeeded.
Then, you'll want to create some tables so - grant it:
SQL> grant create table to mdp;
Grant succeeded.
OK, let's connect as newly created user and do something:
SQL> connect mdp/pdm#xe
Connected.
SQL> create table test (id number);
Table created.
SQL> insert into test id values (1);
1 row created.
SQL> drop table test;
Table dropped.
SQL>
Nice; I can create tables, insert/update/delete/select from them. For beginning, that's quite enough. However, when it turns out that you'd want to, for example, create a view, it won't work until you grant it that privilege:
SQL> create view v_dual as select * From dual;
create view v_dual as select * From dual
*
ERROR at line 1:
ORA-01031: insufficient privileges
SQL> connect sys#xe as sysdba
Enter password:
Connected.
SQL> grant create view to mdp;
Grant succeeded.
SQL> connect mdp/pdm#xe
Connected.
SQL> create view v_dual as select * From dual;
View created.
SQL>
And so forth; don't grant anything just because you might need it - grant it if & when you need it. Especially pay attention to system privileges which can potentially be dangerous if you don't know what you're doing.