oracle對象定義(英文版)-免費閱讀
【正文】 2023 Global Business Solutions, Inc.Database Blocksn Are:l smallest unit of storagel sized by DB_BLOCK_SIZEl same as buffer in database buffer cachen Correspond to O/S blockn Typically sized as 2k, 4k, 8k, or 16kSegmentExtentBlocksCopyright 169。 2023 Global Business Solutions, Inc.Index Segmentsn Created for every indexn Exist as separate physical segments from data segmentn Usually much smaller than associated data segmentBootstrapSegmentRollbackSegmentIndexSegmentIndex SegmentCopyright 169。 2023 Global Business Solutions, Inc.Advantages of Partitionsn Control data storage across physical devicesn Maintain partition transparencyl Programs do not need to reference partitionsl Programs can take advantage of partitionsCopyright 169。 2023 Global Business Solutions, Inc.Index Typesn Single ColumnIndex RowidOrderNo Block.Seq.File007000 0000A .0004 .0003007000 0000A .0005 .0003OrderNo ItemNo Cust.006989 001 ABC 006989 002 XYZ006989 003 USA007000 001 USA007000 002 GBSI007000 003 TEST007000 004 XYZ007234 005 WESTORDER TABLECopyright 169。 2023 Global Business Solutions, Inc.Tablesn Stored in Tablespacesn Organized in rows and columnsn Contain dataTablespaceTables, indexes, etc.DatafilesSegmentExtentBlocksCopyright 169。 2023 Global Business Solutions, Inc.Tablespacesn Largest logical unit of spacen Consist of one or more datafilesn SYSTEM tablespace must existTablespaceCopyright 169。 2023 Global Business Solutions, Inc.Types of Tablespacesn System/Nonsystemn Online/Offlinen ReadWrite/ReadOnlyn TransportableCopyright 169。 2023 Global Business Solutions, Inc.Table Datatypesn CHARn VARCHAR2n NUMBERn DATAn LOBCustomersName Address Phone…..Gee..123 Cherry 555 5555 Copyright 169。 2023 Global Business Solutions, Inc.Index Typesn MultiColumnl Concatenated, positeIndex RowidOrderNo ItemNo Block.Seq.File006989 001 006989 002 OrderNo ItemNo Cust.007000 001 USA007000 002 GBSI007000 003 TEST007234 005 WEST 006989 001 ABC 006989 002 XYZORDER TABLECopyright 169。 2023 Global Business Solutions, Inc.Equipartitionsn Database objects have same logical partitionsn Examplesl Master and detail table l Table and indexOrder TableItem TableCustomer TableCustomer by State Copyright 169。 2023 Global Business Solutions, Inc.Rollback Segmentsn Record before image of modified datan Allow changes to be undone before mitn Suppo
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