oracle對象定義(英文版)(存儲版)
【正文】 rt read consistencyn Support data concurrencyn Support database recoveryn A SYSTEM rollback segment is requiredBootstrapSegmentRollbackSegmentIndexSegmentRollback SegmentCopyright 169。 2023 Global Business Solutions, Inc.Define Database Objects Summaryn Tablespaces are logical collections of database objects with one or more datafilesn Upon creation, space is preallocated for tablespacesTablespaceTables, indexes, etc. DatafilesSegmentExtentBlocksCopyright 169。 2023 Global Business Solutions, Inc.Database Extentsn Consist of a set of contiguous blocksn Serve as space allocation for segmentn Deallocated when segment is removedn First extent created as Initial Extentn Grow by Next ExtentSegmentExtentExtentExtentCopyright 169。 2023 Global Business Solutions, Inc.Data Segmentsn Stores rows for Tablesn Table featuresl Contains user datal Contains Data Dictionary datan Row Featuresl Contain unlimited number of rowsl Span blocks (chaining)l Columns stored side by sideBootstrapSegmentRollbackSegmentIndexSegmentData SegmentCopyright 169。 2023 Global Business Solutions, Inc.Advantages of Partitionsn Reduce time for data loads and index creationn Increase availability of missioncritical databasesn Create partition independencel Enable concurrent operations on separate partitionsl Execute queries on partitions instead of full table scanCopyright 169。 2023 Global Business Solutions, Inc.Index Typesn Uniquel Duplicates not allowedn Nonuniquel Duplicates allowedXCopyright 169。 2023 Global Business Solutions, Inc.Uses of Transportable Tablespacesn Archive OLTP and data warehouse systemsn Transfer data from OLTP to data warehouse staging systemsn Loading data marts from central data warehousesn Publish datan Move index data and avoid rebuildsCopyright 169。 2023 Global Business Solutions, Inc.Define Database Objects OverviewDatabaseTablespaceTables, indexes, etc. DatafilesSegmentExtentBlocksCopyright 169。 2023 Global Business Solutions, Inc.System and Nonsystem Tablespacesn Systeml At least onel Data Dictionaryl Rollbackn Nonsysteml Facilitates Administrationl User/Application Data, Indexesl Rollback and Temporary SegmentsCopyright 169。 2023 Global Business Solutions, Inc.Large Object Datatypen Store Unstructured Informationl Text documentsl Static imagesl Videol AudioCustomersName Address... Photo Greeting Gee.. 123 Cherry Copyright 169。 2023 Global Business Solutions, Inc.Bal
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