Multivalue compression and the indication of nullability are different matters, but with one common task: Collecting information about column values in every row. To keep space requirements low, Teradata stores information about nullability and multivalue compress in the so-called presence bytes. The alert reader might recognize that the name “presence byte” suggests that it indicates

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Continuing the Data Type considerations, here are more issues that demand attention from time to time. Happenstance Nullability Aim for nullability settings that are compliant with the data model and unified across all tables. The cost of a mandatory column left open for null entries is both on the storage side and on the optimizer

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