Data Dictionary

Data Dictionary is a part of Oracle database.
Data Dictionary is a read-only set of tables that provides information about the database.
The data dictionary is structured in tables and views.

A data dictionary contains:

The definitions of all schema objects in the database (tables, views, indexes, clusters, synonyms, sequences, procedures, functions, packages, triggers).
Informations about the schema objects.
Default values for columns.
Integrity constraint information.
The names of Oracle database users.
Privileges and roles each user has been granted.

The data dictionary tables and views are stored SYSTEM tablespace.

Data Dictionary examples

Most data dictionary views come in three versions:

  • USER view – shows information about the schema to which a user is connected.
  • ALL view – shows information about database objects to which the currently connected schema has access.
  • DBA view – shows information about database objects that are allowed only for Database administrator.
  • USER_ARGUMENTS
  • USER_ALL_TABLES
  • USER_CATALOG
  • USER_CONSTRAINTS
  • USER_DATAPUMP_JOBS
  • USER_DB_LINKS
  • USER_DEPENDENCIES
  • USER_ERRORS
  • USER_EXTENTS
  • USER_EXTERNAL_TABLES
  • USER_HOST_ACES
  • USER_INDEXES
  • USER_IDENTIFIERS
  • USER_IND_PARTITIONS
  • USER_JAVA_CLASSES
  • USER_JAVA_POLICY
  • USER_LIBRARIES
  • USER_NESTED_TABLES
  • USER_OBJECTS
  • USER_OBJECT_SIZE
  • USER_OBJECT_TABLES
  • USER_PLSQL_OBJECT_SETTINGS
  • USER_PROCEDURES
  • USER_ROLE_PRIVS
  • USER_RULES
  • USER_SCHEDULER_JOBS
  • USER_SCHEDULER_RUNNING_JOBS
  • USER_SEQUENCES
  • USER_SOURCE
  • USER_STORED_SETTINGS
  • USER_SYNONYMS
  • USER_SYS_PRIVS
  • USER_TABLES
  • USER_TABLESPACES
  • USER_TRIGGERS
  • USER_TRIGGER_COLS
  • USER_VIEWS
  • USER_XML_SCHEMAS