Creating JOOQ query dynamically

问题

I need to create a JOOQ SELECT query dynamically based on the set of parameters. I dont know how to append it dynamically. Please help

Thanks in advance.

回答1:

jOOQ has two types of APIs to construct queries.

The DSL API that allows for creating inline SQL statements in your Java code, e.g.
```
create.select(T.A, T.B).from(T).where(T.X.eq(3).and(T.Y.eq(5)));
```
The "model" API that allows for incremental SQL building. At any time, you can access the "model" API through the getQuery() method on a DSL query object

An example of what you want to do is given in the manual here:

https://www.jooq.org/doc/latest/manual/sql-building/sql-statements/dsl-and-non-dsl/

For instance, optionally adding a join:

DSLContext create = DSL.using(configuration);
SelectQuery query = create.selectQuery();
query.addFrom(AUTHOR);

// Join books only under certain circumstances
if (join)
    query.addJoin(BOOK, BOOK.AUTHOR_ID.equal(AUTHOR.ID));

Result<?> result = query.fetch();

Or, optinally adding conditions / predicates:

query.addConditions(BOOK.TITLE.like("%Java%"));
query.addConditions(BOOK.LANGUAGE_CD.eq("en"));

UPDATE: Given your comments, that's what you're looking for:

// Retrieve search strings from your user input (just an example)
String titleSearchString = userInput.get("TITLE");
String languageSearchString = userInput.get("LANGUAGE");
boolean lookingForTitles = titleSearchString != null;
boolean lookingForLanguages = languageSearchString != null;

// Add only those conditions that the user actually provided:
if (lookingForTitles)
    query.addConditions(BOOK.TITLE.like("%" + titleSearchString + "%"));
else if (lookingForLanguages)
    query.addConditions(BOOK.LANGUAGE_CD.eq(languageSearchString));

Note, you can also use the Field.compare(Comparator, Object) methods:

// Initialise your dynamic arguments
Field<String> field = BOOK.TITLE;
Comparator comparator = Comparator.LIKE;
String value = "%" + titleSearchString + "%";

// Pass them to the field.compare() method
query.addConditions(field.compare(comparator, value));

For more info, consider the org.jooq.SelectQuery Javadoc

来源：https://stackoverflow.com/questions/14051080/creating-jooq-query-dynamically

标签

java

sql

jooq