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- MyBatis-Flex is very lightweight, and it only depends on Mybatis and no other third-party dependencies
- Basic CRUD operator and paging query of Entity class
- Row mapping support, you can add, delete, modify and query the database without entity classes
- Support multiple databases, and expand through dialects flexibly
- Support combined primary keys and different primary key content generation strategies
- Extremely friendly SQL query, IDE automatically prompts and no worries about mistakes
- More little surprises
step 1: write entity class
@Table("tb_account")
public class Account {
@Id(keyType = KeyType.Auto)
private Long id;
private String userName;
private Date birthday;
private int sex;
// getter setter
}step 2: write mapper class(it needs extends BaseMapper)
public interface AccountMapper extends BaseMapper<Account> {
// only Mapper interface define
}step 3: start query data
e.g. 1: query by primary key
class HelloWorld {
public static void main(String... args) {
HikariDataSource dataSource = new HikariDataSource();
dataSource.setJdbcUrl("jdbc:mysql://127.0.0.1:3306/mybatis-flex");
dataSource.setUsername("username");
dataSource.setPassword("password");
MybatisFlexBootstrap.getInstance()
.setDataSource(dataSource)
.addMapper(AccountMapper.class)
.start();
AccountMapper mapper = MybatisFlexBootstrap.getInstance()
.getMapper(AccountMapper.class);
// id = 100
Account account = mapper.selectOneById(100);
}
}e.g.2: query list
// use QueryWrapper to build query conditions
QueryWrapper query = QueryWrapper.create()
.select()
.from(ACCOUNT)
.where(ACCOUNT.ID.ge(100))
.and(ACCOUNT.USER_NAME.like("zhang").or(ACCOUNT.USER_NAME.like("li")));
// execute SQL：
// SELECT * FROM tb_account
// WHERE tb_account.id >= 100
// AND (tb_account.user_name LIKE '%zhang%' OR tb_account.user_name LIKE '%li%' )
List<Account> accounts = mapper.selectListByQuery(query);e.g.3: paging query
// use QueryWrapper to build query conditions
QueryWrapper query = QueryWrapper.create()
.select()
.from(ACCOUNT)
.where(ACCOUNT.ID.ge(100))
.and(ACCOUNT.USER_NAME.like("zhang").or(ACCOUNT.USER_NAME.like("li")))
.orderBy(ACCOUNT.ID.desc());
// execute SQL：
// SELECT * FROM tb_account
// WHERE tb_account.id >= 100
// AND (tb_account.user_name LIKE '%zhang%' OR tb_account.user_name LIKE '%li%' )
// ORDER BY tb_account.id DESC
// LIMIT 40,10
Page<Account> accountPage = mapper.paginate(5, 10, query);QueryWrapper query = new QueryWrapper();
query.select().from(ACCOUNT)
// SQL:
// SELECT * FROM tb_accountQueryWrapper query = new QueryWrapper();
query.select(ACCOUNT.ID,ACCOUNT.USER_NAME).from(ACCOUNT)
// SQL:
// SELECT tb_account.id, tb_account.user_name
// FROM tb_accountQueryWrapper query = new QueryWrapper()
.select(ACCOUNT.ID
, ACCOUNT.USER_NAME
, ARTICLE.ID.as("articleId")
, ARTICLE.TITLE)
.from(ACCOUNT.as("a"), ARTICLE.as("b"))
.where(ACCOUNT.ID.eq(ARTICLE.ACCOUNT_ID));
// SQL:
// SELECT a.id, a.user_name, b.id AS articleId, b.title
// FROM tb_account AS a, tb_article AS b
// WHERE a.id = b.account_id QueryWrapper query = new QueryWrapper()
.select(
ACCOUNT.ID,
ACCOUNT.USER_NAME,
max(ACCOUNT.BIRTHDAY),
avg(ACCOUNT.SEX).as("sex_avg")
).from(ACCOUNT);
// SQL:
// SELECT tb_account.id, tb_account.user_name,
// MAX(tb_account.birthday),
// AVG(tb_account.sex) AS sex_avg
// FROM tb_accountQueryWrapper queryWrapper = QueryWrapper.create()
.select()
.from(ACCOUNT)
.where(ACCOUNT.ID.ge(100))
.and(ACCOUNT.USER_NAME.like("michael"));
// SQL:
// SELECT * FROM tb_account
// WHERE tb_account.id >= ?
// AND tb_account.user_name LIKE ?QueryWrapper queryWrapper = QueryWrapper.create()
.select()
.from(ACCOUNT)
.where(ACCOUNT.ID.ge(100))
.and(
exists(
selectOne().from(ARTICLE).where(ARTICLE.ID.ge(100))
)
);
// SQL:
// SELECT * FROM tb_account
// WHERE tb_account.id >= ?
// AND EXIST (
// SELECT 1 FROM tb_article WHERE tb_article.id >= ?
// )QueryWrapper queryWrapper = QueryWrapper.create()
.select()
.from(ACCOUNT)
.where(ACCOUNT.ID.ge(100))
.and(ACCOUNT.SEX.eq(1).or(ACCOUNT.SEX.eq(2)))
.or(ACCOUNT.AGE.in(18,19,20).or(ACCOUNT.USER_NAME.like("michael")));
// SQL:
// SELECT * FROM tb_account
// WHERE tb_account.id >= ?
// AND (tb_account.sex = ? OR tb_account.sex = ? )
// OR (tb_account.age IN (?,?,?) OR tb_account.user_name LIKE ? )QueryWrapper queryWrapper = QueryWrapper.create()
.select()
.from(ACCOUNT)
.groupBy(ACCOUNT.USER_NAME);
// SQL:
// SELECT * FROM tb_account
// GROUP BY tb_account.user_nameQueryWrapper queryWrapper = QueryWrapper.create()
.select()
.from(ACCOUNT)
.groupBy(ACCOUNT.USER_NAME)
.having(ACCOUNT.AGE.between(18,25));
// SQL:
// SELECT * FROM tb_account
// GROUP BY tb_account.user_name
// HAVING tb_account.age BETWEEN ? AND ?QueryWrapper queryWrapper = QueryWrapper.create()
.select()
.from(ACCOUNT)
.orderBy(ACCOUNT.AGE.asc(), ACCOUNT.USER_NAME.desc().nullsLast());
// SQL:
// SELECT * FROM tb_account
// ORDER BY age ASC, user_name DESC NULLS LASTQueryWrapper queryWrapper = QueryWrapper.create()
.select()
.from(ACCOUNT)
.leftJoin(ARTICLE).on(ACCOUNT.ID.eq(ARTICLE.ACCOUNT_ID))
.where(ACCOUNT.AGE.ge(10));
// SQL:
// SELECT * FROM tb_account
// LEFT JOIN tb_article
// ON tb_account.id = tb_article.account_id
// WHERE tb_account.age >= ?QueryWrapper queryWrapper = QueryWrapper.create()
.select()
.from(ACCOUNT)
.orderBy(ACCOUNT.ID.desc())
.limit(10)
.offset(20);
// MySql:
// SELECT * FROM `tb_account` ORDER BY `id` DESC LIMIT 20, 10
// PostgreSQL:
// SELECT * FROM "tb_account" ORDER BY "id" DESC LIMIT 20 OFFSET 10
// Informix:
// SELECT SKIP 20 FIRST 10 * FROM "tb_account" ORDER BY "id" DESC
// Oracle:
// SELECT * FROM (SELECT TEMP_DATAS.*,
// ROWNUM RN FROM (
// SELECT * FROM "tb_account" ORDER BY "id" DESC)
// TEMP_DATAS WHERE ROWNUM <=30)
// WHERE RN >20
// Db2:
// SELECT * FROM "tb_account" ORDER BY "id" DESC
// OFFSET 20 ROWS FETCH NEXT 10 ROWS ONLY
// Sybase:
// SELECT TOP 10 START AT 21 * FROM "tb_account" ORDER BY "id" DESC
// Firebird:
// SELECT * FROM "tb_account" ORDER BY "id" DESC ROWS 20 TO 301. How to generate "ACCOUNT" class for QueryWrapper by Account.java ?
Build the project by IDE, or execute maven build command: mvn clean package
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