New database for existing user?

Question

Hi,
am I right saying that a new schema in Oracle involves a new user to create?
Say I've got my user already and I just want to create a new schema for this user.
How can I do it?

Answer 1

833519 wrote:
wherever I'm looking I can read this:
schema
A named collection of database objects, including logical structures such as tables and indexes. A schema has the name of the database user who owns it.
---I don't particularly like that definition.
A schema can be a logical database - just like a SQL-Server database. For example, the schema HR can be the Human Resources database with tables like employees, departments, payroll and so on.
A schema can be a user account. Let's say John is the head of a department. A schema can be created for John called JOHN. The HR schema (logical database) can grant select privs to the JOHN schema (user account) on tables and views inside the HR database schema.
It can even be setup in such a way that JOHN can only see his department's staff in the employees, and payroll tables, and a single row for his department in the departments table (this feature is called virtual private databases).
The JOHN schema, besides connection to Oracle rights and selection rights on the HR tables, may have no other rights. So no tables, views and other db objects can be created in the JOHN schema.
The HR schema otoh has the rights to create the db objects. And it may for example not have any create session rights, preventing anyone from directly logging into this schema.
There may be a .Net application for HR. It uses an application schema in Oracle called HR_APP. It may have certain db objects (such as application log tables, application audit tables, etc). It also will have access to the HR schema's db objects.
So an Oracle schema can be used in many different ways - providing flexibility way beyond what other database products provide in this regard.
As for how to use a schema (as a user schema, logical database, app schema, library schema, etc) depends entirely on your requirements - and correctly translating these into secure and flexible Oracle schemas that address these requirements.
In my understanding this means that if I wanna create two databases (collection of tables), which are called 'schemas' in Oracle I also have to create 2 database users.Yes. But these will be logical database schemas. Not end user schemas. For example, you can create a HR schema for a Human Resources database. You can create a MARKETING schema for the Marketing database. (yes, you will use the CREATE USER command to create these 2 logical database schemas - and you would use the same command to create a user schema, developer schema, or any other type of schema)
The HR schema can be specifically setup for the HR database requirements. A space quota of 10Gb. The ability to create tables and stored procedures and views.
Likewise, the MARKETING schema can be setup specifically for marketing. They may need a 50Gb space quota. This database may use object relational features and also need the rights to the SQL advance data types. Etc.
If you want to use the HR database, you can logon as the HR schema. If you want to use the marketing database, you can logon as the MARKETING schema.
Or you can create a user schema - and for this schema user to select tables from the HR database, the HR schema needs to grant specific rights (like select, update, delete and insert) to the user schema on those tables.
Do not let this confuse you. A schema can be many different things, depending on WHAT it can do and HOW it is used. And both these you determine when creating the schema and its rights and its contents (if any).
As already suggested - read the Concepts Guide. See http://tahiti.oracle.com (Oracle documentation portal).