A database management system for managing a database, the database management system comprising a processor (400a, 411) configured to: receive a definition of at least one of a graph vertex and a graph edge of data of the database; generate a schema mapping rule, based on the definition of the at least one of the graph vertex and the graph edge of the data of the database, wherein the schema mapping rule defines a correspondence between the data of the database and a graph representation of the data of the database, the graph representation including the at least one of the graph vertex and the graph edge of the data of the database; and generate, based on the schema mapping rule, a database query for extracting one or more further graph vertices and/or graph edges of the data of the database, wherein the processor (400a, 411) is further configured to store the database query in a database catalog of the database, wherein the processor (400a, 407) is further configured to extract the one or more further graph vertices and/or graph edges of the data of the database based on the database query stored in the database catalog, wherein the processor (400a, 411) is further configured to provide a programming interface, wherein the programming interface is configured to receive one or more programming instructions for at least one of extracting the data from the database and defining the at least one of the graph vertex and the graph edge of the data of the database, wherein the one or more programming instructions of the programming interface comprise a first programming instruction for extracting the data from the database or from the graph representation of the data of the database, wherein the first programming instruction for extracting the data from the database is configured to define the at least one of the graph vertex and the graph edge of the data of the database by recursive reference to the schema mapping rule. receive a definition of at least one of a graph vertex and a graph edge of data of the database; generate a schema mapping rule, based on the definition of the at least one of the graph vertex and the graph edge of the data of the database, wherein the schema mapping rule defines a correspondence between the data of the database and a graph representation of the data of the database, the graph representation including the at least one of the graph vertex and the graph edge of the data of the database; and generate, based on the schema mapping rule, a database query for extracting one or more further graph vertices and/or graph edges of the data of the database, wherein the processor (400a, 411) is further configured to store the database query in a database catalog of the database, wherein the processor (400a, 407) is further configured to extract the one or more further graph vertices and/or graph edges of the data of the database based on the database query stored in the database catalog, wherein the processor (400a, 411) is further configured to provide a programming interface, wherein the programming interface is configured to receive one or more programming instructions for at least one of extracting the data from the database and defining the at least one of the graph vertex and the graph edge of the data of the database, wherein the one or more programming instructions of the programming interface comprise a first programming instruction for extracting the data from the database or from the graph representation of the data of the database, wherein the first programming instruction for extracting the data from the database is configured to define the at least one of the graph vertex and the graph edge of the data of the database by recursive reference to the schema mapping rule.