Oracle Database Concepts: Introducing schema Objects (Introduction to schema Objects)

A database schema (schema) is a logical container of data structures, called schema Objects (schema objects)

Each database user has a pattern that is the same as the user name, such as an HR user with HR mode.

In a product database, the owner of a pattern is typically a database application rather than a person.

In a pattern, each schema object has a unique name. such as Hr.employees represents the Employees table in HR mode.

As shown in the following:

type of pattern object

The most important schema object is a table in a relational database, and Oracle SQL enables you to create and manipulate other types of schema objects. As follows:

1. Index (Indexes)

2. Partitioning (partitions)

3. View (views)

4. Sequence (sequences)

5. Dimensions (Dimensions)

6. Synonyms (synonyms)

7.pl/sql subroutines and packages (PL/SQL subprograms and packages)

Schema Object Storage

In a logical storage structure, some schema objects store data called fragments (segments).

The Oracle database storage mode object is logically in a tablespace (tablespace), where tablespaces and schemas are not related: a table space can contain different schemas, and objects in a schema can be contained in different table spaces. The data for each object is physically contained in one or more data files.

As a possible configuration, one of the table's data Fragments (segment) spans two data files. Both of these data files are in the same table space. A fragment (segment) cannot span more than one table space.

Schema Object Dependency (Dependencies)

Some schema objects refer to other objects, for example, a object refers to a B object, then A is dependent object,b is a referenced object.

The Oracle database provides an automated mechanism to ensure that dependent objects always represent the most recent reference objects.

Oracle Database Concepts: Introducing schema Objects (Introduction to schema Objects)