Introducing Schema Objects
Overview of Oracle Database Schemas
1-2 Oracle Database 2 Day Developer's Guide
relax this rule by allowing the client to issue raw SQL
SELECT
statements, but
requiring it to call PL/SQL subprograms for all business functions that make changes
to the database.
This general discussion sets the charter for your job as an Oracle Database developer:
You need to know about the various types of objects that you can create in the
database, as described in
You need to know the SQL that is used to manage these objects:
CREATE
,
ALTER
,
TRUNCATE
, and
DROP
. This is known as data definition language (DDL), and is
described in
You need to know the SQL language that is used to maintain application data:
INSERT
,
UPDATE
,
DELETE
, and
MERGE
. This is known as data manipulation
language
(DML), and is described in
You need to know the SQL language for querying data:
SELECT
statement and its
various clauses, as described in
You need to know about transactions, and the SQL language for controlling them:
COMMIT
,
SAVEPOINT
, and
ROLLBACK
, as described in
You need to know how to write PL/SQL subprograms and procedural code that
use DDL, DML, transaction control, and queries, as described in
You need to know how to manage your deliverables and how to instantiate your
application in several different databases for the purposes of development itself,
unit testing, integration testing, end-user acceptance testing, education, and
ultimately for deploying your application in a production environment. This
information is in
Overview of Oracle Database Schemas
This section introduces Oracle Database schemas.
Introducing Schema Objects
Oracle Database groups related types of information into logical structures that are
called schemas. When you connect to the database by providing your user name and
password
, you name the schema and indicate that you are its owner. Schemas contain
tables
, which are the basic units of data storage in the database. Using a table, you can
query for information, update it, insert additional data, and delete. Each table contains
rows
that represent the individual data records. The table rows are composed of
columns
that represent the various fields of the record.
In addition to tables, schemas contain many other objects. Indexes are optional
structures that can improve the performance of data retrieval from tables. Indexes are
See Also:
Oracle Database Concepts for information about application
architecture
See Also:
Oracle Database Concepts
