In database

Database

A database is an organized collection of data for one or more purposes, usually in digital form. The data are typically organized to model relevant aspects of reality , in a way that supports processes requiring this information...

 lore, a schema object is a logical data storage structure

Database storage structures

Database tables/indexes are typically stored on hard disk in one of many forms, ordered/unordered Flat files, ISAM, Heaps, Hash buckets or B+ Trees. These have various advantages and disadvantages discussed in this topic. The most commonly used are B+trees and ISAM....

. This possibly originates from the use of the term in the context of Oracle database

Oracle database

The Oracle Database is an object-relational database management system produced and marketed by Oracle Corporation....

s. The term "schema" can have other meanings when talking about non-Oracle databases. This article discusses the Oracle use of the term. For other uses of "schema" in a database context, such as a graphical representation of tables and other objects in a database, see database schema

Database schema

A database schema of a database system is its structure described in a formal language supported by the database management system and refers to the organization of data to create a blueprint of how a database will be constructed...

.

In an Oracle database, associated with each database user is a schema. A schema comprises a collection of schema objects. Examples of schema objects include:

• tables
  Table (database)
  In relational databases and flat file databases, a table is a set of data elements that is organized using a model of vertical columns and horizontal rows. A table has a specified number of columns, but can have any number of rows...
  
  
• views
  View (database)
  In database theory, a view consists of a stored query accessible as a virtual table in a relational database or a set of documents in a document-oriented database composed of the result set of a query or map and reduce functions...
  
  
• sequence
  Sequence
  In mathematics, a sequence is an ordered list of objects . Like a set, it contains members , and the number of terms is called the length of the sequence. Unlike a set, order matters, and exactly the same elements can appear multiple times at different positions in the sequence...
  
  s
• synonyms
  Synonym (database)
  A Synonym is an alias or alternate name for a table, view, Sequence, or other Schema object. They are used mainly to make it easy for users to access database objects owned by other users. They hide the underlying object's identity and make it harder for a malicious program or user to target the...
  
  
• indexes
  Index (database)
  A database index is a data structure that improves the speed of data retrieval operations on a database table at the cost of slower writes and increased storage space...
  
  
• clusters
• database links
• snapshot
  Snapshot (computer storage)
  In computer systems, a snapshot is the state of a system at a particular point in time. The term was coined as an analogy to that in photography. It can refer to an actual copy of the state of a system or to a capability provided by certain systems....
  
  s
• procedure
  Stored procedure
  A stored procedure is a subroutine available to applications that access a relational database system. A stored procedure is actually stored in the database data dictionary.Typical uses for stored procedures include data validation or access control mechanisms...
  
  s
• functions
• packages

On the other hand, non-schema objects may include:

• users
• roles
• contexts
• directory objects

Schema objects do not have a one-to-one correspondence to physical files on disk that store their information. However, Oracle database

Oracle database

The Oracle Database is an object-relational database management system produced and marketed by Oracle Corporation....

s store schema objects logically within a tablespace

Tablespace

A tablespace is a storage location where the actual data underlying database objects can be kept. It provides a layer of abstraction between physical and logical data, and serves to allocate storage for all DBMS managed segments...

 of the database. The data of each object is physically contained in one or more of the tablespace's datafiles. For some objects such as (tables, indexes, and clusters) a database administrator

Database administrator

A database administrator is a person responsible for the design, implementation, maintenance and repair of an organization's database. They are also known by the titles Database Coordinator or Database Programmer, and is closely related to the Database Analyst, Database Modeller, Programmer...

 can specify how much disk space the Oracle RDBMS allocates for the object within the tablespace's datafiles.

There is no necessary relationship between schemas and tablespaces: a tablespace can contain objects from different schemas, and the objects for a single schema can be contained in different tablespaces.

External links

• Schema Objects in Oracle 8i
• Regarding Microsoft
  Microsoft
  Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
  
   Active Directory
  Active Directory
  Active Directory is a directory service created by Microsoft for Windows domain networks. It is included in most Windows Server operating systems. Server computers on which Active Directory is running are called domain controllers....
  
  schema objects:
  • Microsoft MSDN: Active Directory Schema
  • Microsoft TechNet: Understanding Schema
  • Microsoft TechNet Magazine: Extending the Active Directory Schema