动态创建JOOQ查询 [英] Creating JOOQ query dynamically

问题描述

我需要根据参数集动态创建JOOQ SELECT查询。我不知道如何动态追加它。
请帮助

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

提前致谢。

推荐答案

jOOQ有两种类型的API来构造查询。

jOOQ has two types of APIs to construct queries.

• 允许在Java代码中创建内联SQL语句的DSL API，例如

• 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)));

允许增量SQL构建的模型API。您可以随时通过 getQuery（） 方法

您想要做的一个示例在手册中给出：

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 /

例如，可选择添加连接：

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();

或者，可选择添加条件/谓词：

Or, optinally adding conditions / predicates:

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

更新：鉴于您的意见，这就是您所寻找的：

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));

注意，您也可以使用 Field.compare（Comparator，Object） 方法：

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));

有关详细信息，请考虑 org.jooq.SelectQuery Javadoc

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

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