动态创建JOOQ查询 | 动态创建JOOQ查询

本文介绍了动态创建JOOQ查询的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

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:

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 Javadoc

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

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