8.1 Table Definition ¶ 8.1.1 Review of Table as Column Dictionary ¶ Tables are built from dictionaries, so it behooves the cursory reader to review Chapter 5 before proceeding. Just q tables, expressions and functions. There is no separate data-definition language, no separate stored-procedure language and no need to map internal representations to a separate form for persistence. Kdb+ handles relational and time series data in the unified environment of q tables. One important example is time-series data. The fact that q tables comprise ordered column lists makes kdb+ very efficient at storing, retrieving and manipulating sequential data. Moreover, since lists are ordered, so are columns, in contrast to SQL where the order of rows is undefined. Consequently, q tables are column-oriented, in contrast to the row-oriented tables in relational databases. A q table is essentially a collection of named columns implemented as a dictionary. Tables are first-class entities in q, meaning they are data structures that live in memory just like lists or dictionaries. List of RecordsĨ.4.10 Retrieving Records with a Compound Primary Key 8.1.1 Review of Table as Column DictionaryĨ.1.6 Flipped Column Dictionary vs.
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