Sample code for mybatis-flex to implement chain operations

Chain operation​

In MyBatis-Flex, built-in 、 as well asUsed to perform chain query operations and chain operations (modify and delete) on data.

• QueryChain: Chain query
• UpdateChain: Chain update
• DbChain: Chained callDb + Row

QueryChain Example​

For example, the query article list code is as follows:

@SpringBootTest
class ArticleServiceTest {

    @Autowired
    ArticleService articleService;

    @Test
    void testChain() {
        List<Article> articles = ()
            .select(ARTICLE.ALL_COLUMNS)
            .from(ARTICLE)
            .where((100))
            .list();
    }
}

If it is not in the Service, we can also pass(mapper)Method, create one by yourselfQueryChainExample, the code is as follows:

List<Article> articles = (mapper)
    .select(ARTICLE.ALL_COLUMNS)
    .from(ARTICLE)
    .where((100))
    .list();

UpdateChain Example​

Suppose we want to updateAccountofuserNamefor "Zhang San", add 1 on the previous basis, and the update code is as follows:

@Test
public void testUpdateChain1() {
    ()
        .set(Account::getUserName, "Zhang San")
        .setRaw(Account::getAge, "age + 1")
        .where(Account::getId).eq(1)
        .update();
}

When the above method is called, the SQL executed internally by MyBatis-Flex is as follows:

UPDATE `tb_account` SET `user_name` = 'Zhang San' , `age` = age + 1
WHERE `id` = 1

Another example:

@Test
public void testUpdateChain2() {

    //Update data    ()
        .set(Account::getAge, (1))
        .where(Account::getId).ge(100)
        .and(Account::getAge).eq(18)
        .update();

    //Query all data and print    (accountMapper)
        .where(Account::getId).ge(100)
        .and(Account::getAge).eq(18)
        .list()
        .forEach(::println);
}

passUpdateChainconductupdate(), the SQL it executes is as follows:

UPDATE `tb_account` SET `age` = `age` + 1
WHERE  `id` >= 100 AND `age` = 18

QueryChain method​

• one(): Get a data
• list(): Get multiple pieces of data
• page(): Pagination query
• obj(): This method can be used when SQL query only returns 1 column of data and only 1 piece of data
• objList(): This method can be used when SQL query only returns 1 column of data.
• count(): query the number of data strips
• exists(): Whether it exists, determine whether count is greater than 0

QueryChain extension method​

one() series methods​

• one(): Get a data
• oneAs(asType): Query the data and convert it directly into vo, dto, etc.
• oneWithRelations: Query a data and its associated data
• oneWithRelationsAs: Query a data and its associated data, and directly convert it into vo, dto, etc.
• oneOpt: Returns the Optional type and gets a data
• oneAsOpt(asType): Returns the Optional type, querys the data, and directly converts it to vo, dto, etc.
• oneWithRelationsOpt: Returns the Optional type, querying a data and its associated data
• oneWithRelationsAsOpt: Returns the Optional type, querys a data and its associated data, and directly converts it to vo, dto, etc.

list() series methods​

• list(): query the data list
• listWithRelations(): Query the data list and its associated data
• listAs(): Query the data list and convert it directly into vo, dto, etc.
• listWithRelationsAs(): query the data list, and its associated data, and directly convert it into vo, dto, etc.

page() series methods​

• page(page): paging query data list
• pageAs(page): paging query data list and directly convert it into vo, dto, etc.

obj() series methods​

• obj(): Query the first column and the first piece of data
• objAs(asType): Query the first column, and convert the first piece of data to a specified type, such as Long, String, etc.
• objOpt(): Returns the Optional type, querys the first column, and the first piece of data
• objAsOpt(asType): Returns the Optional type, querys the first column, and converts the first piece of data to the specified type, such as Long, String, etc.

objList() series methods​

• objList(): Query the first column
• objListAs(asType): Query the first column and convert it to the specified type, such as Long, String, etc.

Code practical examples​

Example 1: Query the Entity List​

List<Article> articles = ()
    .select(ARTICLE.ALL_COLUMNS)
    .from(ARTICLE)
    .where((100))
    .list();

Example 2: Query 1 Entity data​

Article article = ()
    .select(ARTICLE.ALL_COLUMNS)
    .from(ARTICLE)
    .where((100))
    .limit(1)
    .one();

Example 3: Query VO data (ArticleVo)​

public class ArticleVo {

    private Long id;
    private Long accountId;
    private String title;
    private String content;

    //The content with the most comments    private Long maxComments;

    //getter setter
}

Query code:

ArticleVo articleVo = ()
    .select(
        ARTICLE.ALL_COLUMNS,
        max().as(ArticleVo::maxComments)
    ).from(ARTICLE)
    .where((100))
    .limit(1)
    .oneAs();

Example 4: Many-to-many association query VO data (ArticleVo)​

AndArticle CategoryDefinition:

public class ArticleVo {

    private Long id;
    private Long accountId;
    private String title;
    private String content;

    //Article and classification many-to-many relationship configuration    @RelationManyToMany(
        joinTable = "tb_article_category_mapping", // Intermediate table        selfField = "id", joinSelfColumn = "article_id",
        targetField = "id", joinTargetColumn = "category_id"
    )
    private List<ArticleCategory> categories;

    //getter setter
}

Query code:

ArticleVo articleVo = ()
    .select()
    .from(ARTICLE)
    .where((100))
    .limit(1)
    .oneWithRelationsAs();

Query ArticleVo and its associated data (many-to-many article classification) through the oneWithRelationsAs method. For more information about association queries, please refer to the chapter:"Related Query"。

DbChain Example​

useDbChainNo need to addQueryWrapperandRowThe construction separation can be performed directly.

// Added Row build("tb_account")
    .setId()
    .set("user_name", "zhang san")
    .set("age", 18)
    .set("birthday", new Date())
    .save();

// Query QueryWrapper build("tb_account")
    .select("id", "user_name", "age", "birthday")
    .where("age > ?", 18)
    .list()
    .forEach(::println);

This is the article about the sample code of mybatis-flex implementing chain operations. For more related contents of mybatis-flex chain operations, please search for my previous articles or continue browsing the related articles below. I hope everyone will support me in the future!