Hybrid Storage (HOLAP)

Roll-up and drill-down, slice and dice, drill-across, pivoting, and rotation.

To jump to a higher level of aggregation.

To view data across a single plane.

<p>ROLAP stores data in two-dimensional tables, while MOLAP stores data in a multidimensional database management system.</p> Signup and view all the answers

<p>SCD type 1, SCD type 2, and SCD type 3.</p> Signup and view all the answers

<p>The corresponding data record is overwritten, resulting in the loss of previous information.</p> Signup and view all the answers

<p>A validity interval is added to each data record, allowing for full historicization of dimensional changes.</p> Signup and view all the answers

<p>The existing data record is extended with a new attribute containing the new designation.</p> Signup and view all the answers

<p>The study goals for this unit include learning basic modeling techniques, understanding the analysis possibilities offered by OLAP cubes, knowing how multidimensional models are physically stored, and being aware of the options available for historicizing dimensions.</p> Signup and view all the answers

<p>A multidimensional data model is more flexible than a relational data model because it allows data to be located across multiple dimensions, providing flexible views of the data. In contrast, a relational data model locates data in two dimensions.</p> Signup and view all the answers

<p>Star and snowflake schemas are used for performance-oriented modeling of multidimensional spaces in business intelligence.</p> Signup and view all the answers

<p>The purpose of slowly changing dimensions (SCD) in a data warehouse is to handle changes in dimension tables over time.</p> Signup and view all the answers

<p>The three different ways of recording changes in dimension tables for slowly changing dimensions (SCD) are SCD type 2, SCD type 3, and SCD type 4.</p> Signup and view all the answers

<p>The two different database structures for the physical implementation of a multidimensional data model are the star schema and the snowflake schema.</p> Signup and view all the answers

<p>The purpose of the entity relationship model (ERM) is to structure the communication between users and developers in the conceptual phase of application development, as well as to serve as a basis for database design in the implementation phase.</p> Signup and view all the answers

<p>The major disadvantage of not using a model like ERM when creating relational databases is the potential storage of redundant information, which compromises the consistency of the database and can lead to anomalies.</p> Signup and view all the answers

<p>Normalization is a procedure used to avoid redundancies and inconsistencies in relational databases. It transforms databases into data structures that are free of redundancy or minimize redundancy. It helps manage data more efficiently.</p> Signup and view all the answers

<p>An OLAP cube is a multidimensional data space in the online analytical processing (OLAP) cube model. It consists of dimensions (edges of the cube) and key figures or facts (values at the coordinates inside the cube). Dimensions describe key business figures, while facts are operation-related, quantitative variables.</p> Signup and view all the answers

<p>HOLAP stands for Hybrid Online Analytical Processing. It combines the strengths of relational and multidimensional concepts by using both a relational and a multidimensional database for storage. Detailed data are stored in the relational database, while aggregated data are stored in the multidimensional database. Data access is achieved through a multidimensional query tool.</p> Signup and view all the answers

<p>The two different database structures used in the physical implementation of a multidimensional data model are star schema and snowflake schema.</p> Signup and view all the answers

<p>The star schema consists of a fact table in which the keys for a data cube are managed. The dimension tables are arranged in a star shape around the fact table. There is a separate table for each dimension. Relationships only exist between the fact table and the dimension table, not between the dimension tables. The link between the fact table and the dimension table is achieved by including the primary key of the fact table as a foreign key in the primary keys of the dimension tables.</p> Signup and view all the answers

<p>The star schema has dimension tables arranged in a star shape around the fact table, with relationships only between the fact table and the dimension tables. The snowflake schema has dimension tables surrounded by dimension tables, resulting in hierarchies being split into additional dimension tables. The snowflake schema is normalized with regard to functional dependencies, which can result in reduced performance for queries compared to the star schema.</p> Signup and view all the answers