Once you have created the schema and populated it with tables, it is time to build the database itself.
This involves a use of SQL that is beyond the scope of this course. The following diagram gives you a flavor of the commands involved in creating a table for the course-project database.
(The code assumes a schema named StoriesOnCDOrders already exists.)
To create a schema, you use the CREATE SCHEMA statement. In its simplest form it has the syntax:
CREATE SCHEMA schema_name
CREATE SCHEMA distributedNetworks
By default, a schema belongs to the user who created it (the user ID under which the schema was created). The owner of the schema is the only user ID that can modify the schema unless the owner grants that ability to other users.
To assign a different owner to a schema, you add an AUTHORIZATION clause:
For example, to assign the schema of the Antique Opticals to the user ID DBA, someone could use:
CREATE SCHEMA antiqueOpticals AUTHORIZATION dba
When creating a schema, you can also create additional elements at the same time. To do so, you use braces to group the CREATE statements for the other elements, as in:
CREATE SCHEMA schema_name AUTHORIZATION
// other CREATE statements go here
This automatically assigns the elements with the braces to the schema
An identifier is a name that lets you refer to an object unambiguously within the hierarchy of database objects (whether a
schema, database, column, key, index, view, constraint, or anything created with a CREATE statement). An identifier must be unique within its scope, which defines where
and when it can be referenced. In general:
Database names must be unique on a specified instance of a database server.
Table and view names must be unique within a given schema (or database).
Column, key, index, and constraint names must be unique within a given table or view.
This scheme lets you duplicate names for objects whose scopes do not overlap. You can give the same name to columns in different tables, for example, or to tables in different databases.