Orcl1(data).pptx

DataData DictionaryData files Control filesRedo log filesDatabaseData DictionaryDuring database creation, the Oracle server createsadditional object structures within the data files. Data dictionary tablesDynamic performance tablesData Dictionary TablesDynamic Performance TablesData DictionaryThe data dictionary is a set of read-only tables andviews that record, verify, and provide informationabout its associated database.Describes the database and its objectsIncludes two types of objects:Base tablesStore description of databaseCreated with CREATE DATABASEData Dictionary viewsSummarize base table information Created using catalog.sql scriptData Dictionary ContentsThe data dictionary provides information about:Logical and physical database structureDefinitions and space allocations of objectsIntegrity constraintsUsersRolesPrivilegesAuditingHow the Data Dictionary Is UsedThe data dictionary has three primary uses: The Oracle server uses it to find information about:UsersSchema objectsStorage structuresThe Oracle server modifies it when a DDL statement is executed.Users and DBAs can use it as a read-only reference for information about the database.DBA_xxxAll of the objects in the databaseALL_xxxObjects accessible by the current userUSER_xxxObjects owned by the current userData Dictionary View CategoriesThe data dictionary consists of three main sets of static views distinguished from each other by their scope:DBA: What is in all the schemasALL: What the user can accessUSER: What is in the users schemaDynamic Performance TablesDynamic performance views record current databaseactivity.Views are continually updated while the database is operationalInformation is accessed from:MemoryControl fileDBA uses dynamic views to monitor and tune the databaseDynamic views are owned by SYS userDML is not allowedQuerying the Data Dictionary and Dynamic Performance ViewsData dictionary and dynamic performance views canbe queried for information.A listing of views available can be ret