About Schema Objects

Every object in an Oracle Database belongs to only one schema, and has a unique name with that schema.

Some of the objects that schemas can contain are:

• Tables

  Tables are the basic units of data storage in Oracle Database. Tables hold all user-accessible data. Each table contains rows that represent individual data records. Rows are composed of columns that represent the fields of the records. For more information, see "Creating and Managing Tables".

• Indexes

  Indexes are optional objects that can improve the performance of data retrieval from tables. Indexes are created on one or more columns of a table, and are automatically maintained in the database. For more information, see "Managing Indexes".

• Views

  You can create a view that combines information from several different tables into a single presentation. A view can rely on information from both tables and other views. For more information, see "Creating and Managing Views".

• Sequences

  When all records of a table must be distinct, you can use a sequence to generate a serial list of unique integers for numeric columns, each of which represents the ID of one record. For more information, see "Creating and Managing Sequences".

• Synonyms

  Synonyms are aliases for schema objects. You can use synonyms for security and convenience; for example, to hide the ownership of an object or to simplify SQL statements. For more information, see "Creating and Managing Synonyms".

• Stored subprograms

  Stored subprograms (also called schema-level subprograms) are procedures and functions that are stored in the database. They can be invoked from client applications that access the database. For more information, see "Developing Stored Subprograms and Packages".

  Triggers are stored subprograms that are automatically run by the database when specified events occur in a particular table or view. Triggers can restrict access to specific data, perform logging, or audit data. For more information, see "Using Triggers".

• Packages

  A package is a group of related subprograms, along with the explicit cursors and variables they use, stored in the database as a unit, for continued use. Like stored subprograms, packaged subprograms can be invoked from client applications that access the database. For more information, see "Developing Stored Subprograms and Packages".

Typically, the objects that an application uses belong to the same schema.