動態創建JOOQ查詢

Question

我需要基於這組參數動態地創建一個JOOQ SELECT查詢。我不知道如何動態追加它。 請幫忙

在此先感謝。

Answer 1

jOOQ有兩種類型的API來構造查詢。

• 允許在Java代碼中創建內聯SQL語句的DSL API，例如，

  create.select(T.A, T.B).from(T).where(T.X.eq(3).and(T.Y.eq(5))); 
  

• 「模型」 的API，允許增量SQL建設。

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

  ：在任何時候，你可以在DSL查詢對象

你想在這裏做手冊中給出的代碼示例上通過getQuery()方法訪問「模型」 API

例如，任選地加入加入：

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，optinally添加條件/謂詞：

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

UPDATE：考慮您的意見，這就是你要找的內容：

// 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)); 

請注意，您還可以使用Field.compare(Comparator, Object)方法：

// 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)); 

欲瞭解更多信息，考慮org.jooq.SelectQuery Javadoc