Question - What Is The Technical Structure Of Indexes?
Answer -
Indexes, like tables, are implemented as B* trees in SAP MaxDB. These consist of a root node that forms a tree with the subsequent nodes.
The complete index key and the references to the table data are in the lowest level of the index tree, otherwise known as the leaf level. The database system does not use physical items to identify these references, but instead these are saved in the primary key of the data records. The data record is identified by the primary key (the physical item of this data record is determined via the converter).
Since access to the data does not follow the sequence Primary key -> Data, but rather Data -> Primary key, it is also known as an inversion.
The idea behind this is that the relational table design provides for the fact that all data is dependent on a unique primary key.
While the access Primary key -> Data always collects one or no rows, the access Data -> Primary key collects no, one or multiple rows.