JOOQ Object Oriented Querying
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|
Developer(s) | Data Geekery GmbH |
---|---|
Stable release | 3.19.10
/ June 14, 2024[1] |
Repository | github |
Written in | Java |
Operating system | Cross-platform |
Platform | Java |
Type | Object–relational mapping |
License | Dual-licensed: Apache-2.0 and commercial |
Website | www |
jOOQ Object Oriented Querying, commonly known as jOOQ, is a light database-mapping software library in Java that implements the active record pattern. Its purpose is to be both relational and object oriented by providing a domain-specific language to construct queries from classes generated from a database schema.[citation needed]
Paradigm
[edit]jOOQ claims that SQL should come first in any database integration. Thus, it does not introduce a new textual query language, but rather allows for constructing plain SQL from jOOQ objects and code generated from a database schema. jOOQ uses JDBC to call the underlying SQL queries. [citation needed]
While it provides abstraction on top of JDBC, jOOQ does not have as much functionality and complexity as standard object–relational mapping libraries such as EclipseLink or Hibernate.[citation needed]
jOOQ's closeness to SQL has advantages over typical object–relational mapping libraries. [citation needed] SQL has many features that cannot be used in an object oriented programming paradigm; this set of differences is referred to as the object–relational impedance mismatch. By being close to SQL, jOOQ helps to prevent syntax errors and type mapping problems. [citation needed] Also, variable binding is taken care of. It is also possible in jOOQ to create very complex queries, that involve aliasing, unions, nested selects and complex joins. jOOQ also supports database-specific features, such as UDTs, enum types, stored procedures and native functions. [citation needed]
Example
[edit]A nested query selecting from an aliased table
-- Select authors with books that are sold out
SELECT * FROM AUTHOR a
WHERE EXISTS (SELECT 1
FROM BOOK
WHERE BOOK.STATUS = 'SOLD OUT'
AND BOOK.AUTHOR_ID = a.ID);
And its equivalent in jOOQ DSL:
// Use the aliased table in the select statement
create.selectFrom(table("AUTHOR").as("a"))
.where(exists(selectOne()
.from(table("BOOK"))
.where(field("BOOK.STATUS").equal(field("BOOK_STATUS.SOLD_OUT")))
.and(field("BOOK.AUTHOR_ID").equal(field("a.ID")))));
Or more simply, using code generation from the database metadata to generate constants:
// Use the aliased table in the select statement
final Author a = AUTHOR.as("a");
create.selectFrom(a)
.where(exists(selectOne()
.from(BOOK)
.where(BOOK.STATUS.equal(BOOK_STATUS.SOLD_OUT))
.and(BOOK.AUTHOR_ID.equal(a.ID))));
See also
[edit]References
[edit]- ^ "Tags · jOOQ/jOOQ". github.com. Retrieved 2024-06-19.
External links
[edit]- jOOQ Home
- Using Spring Boot with jOOQ
- JSR-341
- JaQu Archived 2021-05-05 at the Wayback Machine
- Linq4j
- Quaere
- QueryDSL