Database Language Extended to Accommodate Entity-Relationship Models

• US 20150074139A1
• Filed: 09/06/2013
• Published: 03/12/2015
• Est. Priority Date: 09/06/2013
• Status: Active Grant

• Current Assignee: SAP SE
• Original Assignee: SAP AG (SAP SE)
• Inventors: Falter, Timm, Hutzel, Daniel, Baeuerle, Stefan, Gruenhagen, Andreas
• Granted Patent: US 9,442,977 B2
• Time in Patent Office: Days
• US Class Current: 707/769
• CPC Class Codes: G06F 16/245 Query processing
• CPC Class Codes: G06F 16/2456 Join operations
• CPC Class Codes: G06F 16/288 Entity relationship models

Abstract

Embodiments extend the relational model and language of standard SQL, to recognize features of higher level entity-relationship models (ERMs). SQL extensions implemented in the data design language (DDL) incorporate Entities (and Views) having custom-defined/semantic structure, rather than being limited to primitive types (e.g. flat tables as in standard SQL). Entities are defined similar to structured types with an underlying persistency, but with a uniquely identifying leading key. In DDL, these entities are combined with associations in the data model. The associations of the extended SQL reflect relationships between entities in the ERM. Associations are specified by adding an element to a source entity, with an association type pointing to a target entity. This may be complemented by providing optional information (e.g., cardinality, keys, filter conditions), up to a complete JOIN condition. In the query language (QL), JOINs may be replaced by the use of simple path expressions.

Claims

1. A computer-implemented method comprising:

providing a database organized according to a relational model;

providing a database engine in communication with the database utilizing a language describing the relational model;

providing an application comprising an entity-relationship model (ERM) including a first entity, a second entity, and a relationship between the first entity and the second entity; and

causing a query engine of the application to communicate a query to the database engine utilizing a language extension comprising,

a first structured entity type including a first key and indicating the first entity,

a second structured entity type including a second key and indicating the second entity, and

a third structured association type reflecting the relationship; and

causing the database engine to return a query result to the query engine based upon the language extension.

2. The computer-implemented method of claim 1 wherein the language comprises SQL.

3. The computer-implemented method of claim 1 wherein the query engine communicates to the database engine, the third structured association type complemented by further information.

4. The computer-implemented method of claim 3 wherein the further information is selected from at least one of, cardinality information, key information, and an additional filter condition.

5. The computer-implemented method of claim 4 wherein the third structured association type in combination with the further information, amount to a join condition.

6. The computer-implemented method of claim 1 wherein the database comprises an in-memory database.

7. A non-transitory computer readable storage medium embodying a computer program for performing a method, said method comprising:

providing a database organized according to a relational model;

providing a database engine in communication with the database utilizing a language describing the relational model;

providing an application comprising an entity-relationship model (ERM) including a first entity, a second entity, and a relationship between the first entity and the second entity; and

causing a query engine of the application to communicate a query to the database engine utilizing a language extension comprising,

a first structured entity type including a first key and indicating the first entity,

a second structured entity type including a second key and indicating the second entity, and

a third structured association type reflecting the relationship; and

causing the database engine to return a query result to the query engine based upon the language extension.

8. A non-transitory computer readable storage medium as in claim 7 wherein the language comprises SQL.

9. A non-transitory computer readable storage medium as in claim 7 wherein the query engine communicates to the database engine, the third structured association type complemented by further information.

10. A non-transitory computer readable storage medium as in claim 9 wherein the further information is selected from at least one of, cardinality information, key information, and an additional filter condition.

11. A non-transitory computer readable storage medium as in claim 10 wherein the third structured association type in combination with the further information, amount to a join condition.

12. A non-transitory computer readable storage medium as in claim 7 wherein the database comprises an in-memory database.

13. A computer system comprising:

one or more processors;

a software program, executable on said computer system, the software program configured to;

provide a database organized according to a relational model;

provide a database engine in communication with the database utilizing a language describing the relational model;

provide an application comprising an entity-relationship model (ERM) including a first entity, a second entity, and a relationship between the first entity and the second entity; and

cause a query engine of the application to communicate a query to the database engine utilizing a language extension comprising,

a first structured entity type including a first key and indicating the first entity,

a second structured entity type including a second key and indicating the second entity, and

a third structured association type reflecting the relationship; and

causing the database engine to return a query result to the query engine based upon the language extension.

14. A computer system as in claim 13 wherein the language comprises SQL.

15. A computer system as in claim 13 wherein the query engine communicates to the database engine, the third structured association type complemented by further information.

16. A computer system as in claim 15 wherein the further information is selected from at least one of, cardinality information, key information, and an additional filter condition.

17. A computer system as in claim 16 wherein the third structured association type in combination with the further information, amount to a join condition.

18. A computer system as in claim 13 wherein the database comprises an in-memory database.