SQL extended with transient fields for calculation expressions in enhanced data models

• US 10,095,758 B2
• Filed: 05/03/2016
• Issued: 10/09/2018
• Est. Priority Date: 09/06/2013
• Status: Active Grant

• Current Assignee: SAP SE
• Original Assignee: SAP SE
• Inventors: Hutzel, Daniel, Falter, Timm, Baeuerle, Stefan
• Primary Examiner(s): Somers, Marc S
• Application Number:
  US15/145,559
• Publication Number:
  US 20160246858A1
• Time in Patent Office: 889 Days
• CPC Class Codes: G06F 16/2438 Embedded query languages
• CPC Class Codes: G06F 16/2445 Data retrieval commands; View definitions
• CPC Class Codes: G06F 16/24561 Intermediate data storage techniques for performance improvement
• CPC Class Codes: G06F 16/24564 Applying rules; Deductive queries
• CPC Class Codes: G06F 16/248 Presentation of query results
• CPC Class Codes: G06F 16/288 Entity relationship models
• CPC Class Codes: G06F 16/90335 Query processing

Abstract

A database language (e.g. SQL) is extended to define a transient field whose value is derived from data stored in a database. The value of the transient field is calculated by the database engine for consumption as needed by the application layer, for example as part of a particular data model. The value of the transient field may not be materialized as a persistent field in the underlying database table, or may be selectively materialized based upon a heuristic or hint. Certain embodiments may implement the transient field as a basic elaboration on standard SQL utilizing an identifier. Some embodiments may implement the transient field as an entity where SQL has been extended to accommodate concepts of a higher-level Entity Relationship Model (ERM). The use of constants and/or floating values (e.g. a current time) in connection with transient fields, is also disclosed.

Claims

1. A computer-implemented method comprising:

providing an in-memory database comprising data of a first type;

causing an in-memory database engine to receive from a query engine implemented within the in-memory database, a query in a database language defining a transient field, wherein the database language is extended to include an entity of an entity-relationship model, and the transient field is defined by the entity;

causing the in-memory database engine to communicate with the in-memory database to generate a query result from the query, wherein the in-memory database engine fills in a value for the transient field derived at least in part from data of a second type materialized in a persistent field in the in-memory database and comprising a constant or a floating value, wherein the value for the transient field is only persistently materialized based upon a hint comprising a directive in a declaration of the transient field in the entity-relationship model; and

causing the in-memory database engine to communicate the query result to the query engine for display to a user.

2. A computer-implemented method as in claim 1 wherein the transient field is defined in the database language by an identifier prepended with a modifier.

3. A computer-implemented method as in claim 2 wherein the database language comprises Structured Query Language (SQL).

4. A computer-implemented method as in claim 2 wherein the data of the second type comprises a constant.

5. A computer-implemented method as in claim 4 wherein the modifier turns an element definition into a declaration of an alias name for a literal expression.

6. A computer-implemented method as in claim 4 further comprising omitting an explicit type declaration.

7. A computer-implemented method as in claim 1 wherein the data of the second type comprises the floating value specifying a present time.

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

providing an in-memory database comprising data of a first type;

causing an in-memory database engine to receive from a query engine implemented within the in-memory database, a query in a database language defining a transient field by an identifier prepended with a modifier, wherein the database language is extended to include an entity of an entity-relationship model, and the transient field is defined by the entity;

causing the in-memory database engine to communicate with the in-memory database to generate a query result from the query, wherein the in-memory database engine fills in a value for the transient field derived at least in part from the data of the second type materialized in a persistent field in the in-memory database and comprising a constant or a floating value, wherein the value for the transient field is only persistently materialized based upon a hint comprising a directive in a declaration of the transient field in the entity relationship model; and

causing the in-memory database engine to communicate the query result to the query engine for display to a user.

9. A non-transitory computer readable storage medium as in claim 8 wherein database language comprises Structured Query Language (SQL).

10. A non-transitory computer readable storage medium as in claim 8 wherein the data of the second type comprises a constant, and the modifier turns an element definition into a declaration of an alias name for a literal expression.

11. A non-transitory computer readable storage medium as in claim 8 wherein the data of the second type comprises the floating value specifying a present time.

12. A computer system comprising:

one or more processors;

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

provide an in-memory database comprising data of a first type;

cause an in-memory database engine to receive from a query engine implemented within the in-memory database, a query in a database language defining a transient field, wherein the database language is extended to include an entity of an entity-relationship model, and the transient field is defined by the entity;

cause the in-memory database engine to communicate with the in-memory database to generate a query result from the query, wherein the database engine fills in a value for the transient field derived at least in part from data of a second type materialized in a persistent field in the in-memory database and comprising a constant or a floating value, wherein the value for the transient field is only persistently materialized based upon a hint comprising a directive in a declaration of the transient field in the entity-relationship model; and

cause the in-memory database engine to communicate the query result to the query engine for display to a user.

13. A computer system as in claim 12 wherein the transient field is defined in the database language by an identifier prepended with a modifier.

14. A computer system as in claim 13 wherein the data of the second type comprises a constant, and the modifier turns an element definition into a declaration of an alias name for a literal expression.

15. A computer system as in claim 12 wherein the data of the second type comprises a floating value specifying a present time.