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Chapter 18

Chapter 18. Data movement & distribution. LOAD. Utility used to perform bulk inserts of data into database tables Adds rows to a table Replaces all existing rows with new data Better to create all indexes before loading data into table Plan for concurrent processing. UNLOAD.

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Chapter 18

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  1. Chapter 18 Data movement & distribution

  2. LOAD • Utility used to perform bulk inserts of data into database tables • Adds rows to a table • Replaces all existing rows with new data • Better to create all indexes before loading data into table • Plan for concurrent processing

  3. UNLOAD • Utility that moves data or copies data • Reads data from a database and writes it to an output data vile • Can use image copy backups • Abilities • Use with LOAD

  4. Unload continued • Data encoding scheme (EBCDIC, ASCII, UNICODE) • Floating –point data • Limiting UNLOAD data • Unloading from VIEWS

  5. Test data • Both LOAD and UNLOAD can be used to create test data sets

  6. EXPORT and IMPORT • EXPORT utility reads data from a table and places it into an external file • IMPORT reads an external file created by EXPORT and inserts the data into a table

  7. ETL Software • Extract, transform, load • Used to populate data warehouses and data marts from other databases and other sources

  8. Replication • Can use replication and propagation • Repeating stored data at other locations (replication) • Migration of changed data (propogation)

  9. Messaging Software • Messaging software or message queueing software or application integration • Provides APIs to read and write formatted message to and from a queue

  10. Distributed Databases • Distributed vs centralized • Autonomy • Isolation • transparency

  11. Working with Networks • Minimize network traffic by retrieving only data needed • Use methods that encourage sending data over network in blocks (not rows) • Access local data instead of remote data

  12. Distribution Standards • Two standards • DRDA – distributed relational database architecture (IBMs protocol) • RDA – remote database access (competing protocol developed by ISO and ANSI) • Gateways can also be used

  13. Accessing Distributed Data • Need to help application developers match the DBMS capabilities • Remote request (single request to a single location) • Remote unit of work (single application access data from multiple location) – programmer must build units of work for each location

  14. Access continued • Distributed unit of work (more than one DBMS can be accessed per unit of work, multiple SQL statements can read/write data at multiple servers within a single unit of work) • Distributed request (single SQL statement can access multiple data from more than one location – robust)

  15. Two-phase Commit • When distributing units of work need to have protocol for committing transactions

  16. Distributed Chain • Computer hardware, local OS, networking software and local databases for the requester • Network hardware, wiring, gateways, routers and hubs • Any middleware or transaction processing system used by the requester or the server

  17. Chain continued • The computer hardware, local OS, networking software and databases on the server • Disk storage and storage management software

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