The descriptions of the capabilities and limitations of using different forms of the update, reorganization, and modeling processes on data set descriptions are divided in the following categories:
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Data set alterations
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Aggregate items
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Count items
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Record type items
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Data items
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Filler items
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Group items
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Link items
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Population items
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Variable-format part
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Global items
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Data set logical options
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Data set physical options
The DASDL compiler uses the population value to compute values for the AREAS, AREASIZE, and BLOCKSIZE options for data sets; and for the AREAS, AREASIZE, and TABLESIZE options for sets and subsets. Thus, changing the population value can affect these options. Changing the population of a data set can also change the population of sets and subsets which reference the data set, because sets and subsets inherit the population of the data set by default.
Both the update and reorganization processes can be used to change the population value.
When the reorganization process is used, the population value can be increased or decreased as desired. The new population value is used to compute new values for the AREAS, AREASIZE, BLOCKSIZE, and TABLESIZE options; and the reorganization process then reformats the files using these new values. Alternatively, the AREAS, AREASIZE, BLOCKSIZE, and TABLESIZE options can be specified explicitly in DASDL.
When an update process is used, the AREASIZE and BLOCKSIZE options must not change. DASDL computes a new value for the AREAS option based on the new population value.
