Multiindeks

Multiindeks, or multi-index, is a data organization concept that refers to indexing data by multiple keys or levels to represent multi-dimensional information within a single data structure. It enables hierarchical or composite indexing.

In practice, a multiindeks uses a set of levels (for example, region, year, product) and associates each data item with a tuple of level values. This creates a navigable structure allowing slicing by one or more levels and aggregated summaries across levels.

Common contexts include data analysis libraries such as pandas, databases with composite keys, or data warehouses. In pandas, a MultiIndex allows a DataFrame to have more than one index level; in SQL, composite keys serve a similar purpose for constraints and efficient lookups.

Advantages of a multiindeks include expressive power and a natural representation of hierarchies, as well as efficient grouping and aggregations across levels. Drawbacks include added complexity, potential performance costs, maintenance overhead, and the need for careful design to avoid inefficiencies.

Related concepts include hierarchical indexing, composite keys, multi-dimensional arrays, and pivot tables. The term is used across data processing domains to describe structures that support multi-level or multi-key access, enabling flexible data retrieval and analysis.