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IBM DB2 for iSeries - Physical and Logical Files

Physical Files

A physical file is a database file that stores data. It also contains a description how data is actually stored in the database.

From the perspective of the SQL standard, physical files are identical to tables.

  • File Member

Physical files can contain one or more members. Members are different sets of data, each with the same format, within one database file (SQL table).

  • Record

A record is a group of related data within a file. From the perspective of the SQL standard, records are identical to rows.

Logical Files

A logical file is a database file that logically represents one or more physical files. Logical files do not contain data records, but they define record formats. The data records are contained in the physical files associated with the logical files.

Logical files let users access data in a sequence and format that is different from the physical files they represent.

From the perspective of the SQL standard, logical files are identical to views and indexes.

Source Files

A source file contains source statements for high-level language programs and data description specifications (DDS).


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sqlways/db2/iseries-physical-logical-files.txt · Last modified: March 20, 2013, 03:52:20 AM (external edit)
 
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