### Example Query Result Output

Source: https://mybatis-flex.com/zh/base/relations-query.html

Example of the final mapped `UserVO` objects after the join query execution.

```txt
UserVO{userId='1', userName='admin', roleList=[Role{roleId=1, roleKey='admin', roleName='超级管理员'}]}
UserVO{userId='2', userName='ry', roleList=[Role{roleId=2, roleKey='common', roleName='普通角色'}]}
UserVO{userId='3', userName='test', roleList=[Role{roleId=1, roleKey='admin', roleName='超级管理员'}, Role{roleId=2, roleKey='common', roleName='普通角色'}]}
```

--------------------------------

### EnjoyTemplate Implementation Example

Source: https://mybatis-flex.com/zh/others/codegen.html

Code example for the built-in EnjoyTemplate, demonstrating how to configure a custom template engine for code generation.

```java
public class EnjoyTemplate implements ITemplate {

    private Engine engine;

    public EnjoyTemplate() {
        Engine engine = Engine.use(engineName);
        if (engine == null) {
            engine = Engine.create(engineName, e -> {
                e.addSharedStaticMethod(StringUtil.class);
                e.setSourceFactory(new FileAndClassPathSourceFactory());
            });
        }
        this.engine = engine;

        // 以下配置将支持 user.girl 表达式去调用 user 对象的 boolean isGirl() 方法
        Engine.addFieldGetterToFirst(new FieldGetters.IsMethodFieldGetter());
    }

    @Override
    public void generate(Map<String, Object> params, String templateFilePath, File generateFile) {
        if (!generateFile.getParentFile().exists() && !generateFile.getParentFile().mkdirs()) {
            throw new IllegalStateException("Can not mkdirs by dir: " + generateFile.getParentFile());
        }
        // 开始生成文件
        try (FileOutputStream fileOutputStream = new FileOutputStream(generateFile)) {
            engine.getTemplate(templateFilePath).render(params, fileOutputStream);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
```

--------------------------------

### SELECT * Example

Source: https://mybatis-flex.com/zh/base/querywrapper.html

Examples demonstrating how to use QueryWrapper to select all columns or specific columns from a table.

```java
QueryWrapper query1 = new QueryWrapper();
query1.select(ACCOUNT.ID, ACCOUNT.USER_NAME)
    .from(ACCOUNT);

QueryWrapper query2 = new QueryWrapper();
query2.select().from(ACCOUNT);
```

--------------------------------

### SELECT ... AS Example

Source: https://mybatis-flex.com/zh/base/querywrapper.html

An example showing how to use QueryWrapper to select columns with aliases.

```java
QueryWrapper query = new QueryWrapper()
    .select(
          ACCOUNT.ID.as("accountId")
        , ACCOUNT.USER_NAME)
    .from(ACCOUNT.as("a"));
```

--------------------------------

### MyBatis-Flex Banner Example

Source: https://mybatis-flex.com/zh/faq.html

This is the expected Banner information printed by MyBatis-Flex during startup.

```text
  __  __       _           _   _       _____ _
 |  \/  |_   _| |__   __ _| |_(_)___  |  ___| | _____  __
 | |\/| | | | | '_ \ / _` | __| / __| | |_  | |/ _ \ \/ /
 | |  | | |_| | |_) | (_| | |_| \__ \ |  _| | |  __/>  <
 |_|  |_|\__, |_.__/ \__,_|\__|_|___/ |_|   |_|\___/_/\_\
         |___/ v1.5.4 https://mybatis-flex.com
```

--------------------------------

### Query Top-Level Menus

Source: https://mybatis-flex.com/zh/base/relations-query.html

Example of querying top-level menus using QueryWrapper and relation mapping.

```java
QueryWrapper qw = QueryWrapper.create();
qw.where(MENU.PARENT_ID.eq(0));

List<Menu> menus = menuMapper.selectListWithRelationsByQuery(qw);
System.out.println(JSON.toJSONString(menus));
```

--------------------------------

### SELECT Multiple Tables Example

Source: https://mybatis-flex.com/zh/base/querywrapper.html

An example demonstrating how to use QueryWrapper to select data from multiple tables with join conditions.

```java
QueryWrapper 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));
```

--------------------------------

### With Select Example 2

Source: https://mybatis-flex.com/zh/base/querywrapper.html

Shows creating a CTE with specified columns and values using `with().asValues()`.

```java
QueryWrapper query = new QueryWrapper()
    .with("xxx", "id", "name").asValues(
        Arrays.asList("a", "b"),
        union(
            select().from(ARTICLE).where(ARTICLE.ID.ge(200))
        )
    )
    .from(ACCOUNT)
    .where(ACCOUNT.SEX.eq(1));

System.out.println(query.toSQL());
```

```sql
WITH xxx(id, name)
    AS (VALUES (a, b) UNION (SELECT * FROM `tb_article` WHERE `id` >= 200))
SELECT * FROM `tb_account` WHERE `sex` = 1
```

--------------------------------

### Where Clause Example

Source: https://mybatis-flex.com/zh/base/querywrapper.html

Demonstrates basic usage of the `where()` and `and()` clauses for filtering.

```java
QueryWrapper queryWrapper=QueryWrapper.create()
    .select()
    .from(ACCOUNT)
    .where(ACCOUNT.ID.ge(100))
    .and(ACCOUNT.USER_NAME.like("michael"));
```

```sql
SELECT * FROM tb_account
WHERE id >=  ?
AND user_name LIKE  ?
```

--------------------------------

### union, union all

Source: https://mybatis-flex.com/zh/base/querywrapper.html

Example of using union and unionAll with QueryWrapper.

```java
QueryWrapper query = new QueryWrapper()
    .select(ACCOUNT.ID)
    .from(ACCOUNT)
    .orderBy(ACCOUNT.ID.desc())
    .union(select(ARTICLE.ID).from(ARTICLE))
    .unionAll(select(ARTICLE.ID).from(ARTICLE));
```

--------------------------------

### With Select Example 1

Source: https://mybatis-flex.com/zh/base/querywrapper.html

Illustrates creating a Common Table Expression (CTE) using `with().asSelect()`.

```java
QueryWrapper query = new QueryWrapper()
        .with("CTE").asSelect(
                select().from(ARTICLE).where(ARTICLE.ID.ge(100))
        )
        .select()
        .from(ACCOUNT)
        .where(ACCOUNT.SEX.eq(1));

System.out.println(query.toSQL());
```

```sql
WITH CTE AS (SELECT * FROM `tb_article` WHERE `id` >= 100)
SELECT * FROM `tb_account` WHERE `sex` = 1
```

--------------------------------

### Column Calculation Example 1: Addition

Source: https://mybatis-flex.com/zh/base/querywrapper.html

Illustrates how to perform addition on a column and alias the result.

```java
QueryWrapper query = new QueryWrapper()
    .select(ACCOUNT.ID.add(100).as("x100"))
    .from(ACCOUNT);

String sql = query.toSQL();
```

--------------------------------

### Select Case When Example 2

Source: https://mybatis-flex.com/zh/base/querywrapper.html

Demonstrates another `case_()` usage with a direct value comparison.

```java
QueryWrapper queryWrapper = QueryWrapper.create()
        .select(
                ACCOUNT.ALL_COLUMNS,
                case_(ACCOUNT.ID)
                    .when(100).then(100)
                    .when(200).then(200)
                    .else_(300).end().as("result")
        )
        .from(ACCOUNT)
        .where(ACCOUNT.USER_NAME.like("michael"));
```

```sql
SELECT *,
       (CASE `id`
           WHEN 100 THEN 100
           WHEN 200 THEN 200
           ELSE 300 END) AS `result`
FROM `tb_account`
WHERE `user_name` LIKE  ?
```

--------------------------------

### Column Calculation Example 2: Sum and Multiply

Source: https://mybatis-flex.com/zh/base/querywrapper.html

Demonstrates using aggregate functions like SUM with column multiplication.

```java
QueryWrapper query = new QueryWrapper()
    .select(sum(ACCOUNT.ID.multiply(ACCOUNT.AGE)).as("total_x"))
    .from(ACCOUNT);
```

--------------------------------

### Code Generation Example

Source: https://mybatis-flex.com/zh/others/codegen.html

Write a class with a main method to configure the data source and generate code.

```java
public class Codegen {

    public static void main(String[] args) {
        //配置数据源
        HikariDataSource dataSource = new HikariDataSource();
        dataSource.setJdbcUrl("jdbc:mysql://127.0.0.1:3306/your-database?characterEncoding=utf-8");
        dataSource.setUsername("root");
        dataSource.setPassword("******");

        //创建配置内容，两种风格都可以。
        GlobalConfig globalConfig = createGlobalConfigUseStyle1();
        //GlobalConfig globalConfig = createGlobalConfigUseStyle2();

        //通过 datasource 和 globalConfig 创建代码生成器
        Generator generator = new Generator(dataSource, globalConfig);

        //生成代码
        generator.generate();
    }

    public static GlobalConfig createGlobalConfigUseStyle1() {
        //创建配置内容
        GlobalConfig globalConfig = new GlobalConfig();

        //设置根包
        globalConfig.setBasePackage("com.test");

        //设置表前缀和只生成哪些表
        globalConfig.setTablePrefix("tb_");
        globalConfig.setGenerateTable("tb_account", "tb_account_session");

        //设置生成 entity 并启用 Lombok
        globalConfig.setEntityGenerateEnable(true);
        globalConfig.setEntityWithLombok(true);
        //设置项目的JDK版本，项目的JDK为14及以上时建议设置该项，小于14则可以不设置
        globalConfig.setEntityJdkVersion(17);

        //设置生成 mapper
        globalConfig.setMapperGenerateEnable(true);

        //可以单独配置某个列
        ColumnConfig columnConfig = new ColumnConfig();
        columnConfig.setColumnName("tenant_id");
        columnConfig.setLarge(true);
        columnConfig.setVersion(true);
        globalConfig.setColumnConfig("tb_account", columnConfig);

        return globalConfig;
    }

    public static GlobalConfig createGlobalConfigUseStyle2() {
        //创建配置内容
        GlobalConfig globalConfig = new GlobalConfig();

        //设置根包
        globalConfig.getPackageConfig()
                .setBasePackage("com.test");

        //设置表前缀和只生成哪些表，setGenerateTable 未配置时，生成所有表
        globalConfig.getStrategyConfig()
                .setTablePrefix("tb_")
                .setGenerateTable("tb_account", "tb_account_session");

        //设置生成 entity 并启用 Lombok
        globalConfig.enableEntity()
                .setWithLombok(true)
                .setJdkVersion(17);

        //设置生成 mapper
        globalConfig.enableMapper();

        //可以单独配置某个列
        ColumnConfig columnConfig = new ColumnConfig();
        columnConfig.setColumnName("tenant_id");
        columnConfig.setLarge(true);
        columnConfig.setVersion(true);
        globalConfig.getStrategyConfig()
                .setColumnConfig("tb_account", columnConfig);

        return globalConfig;
    }
}
```

--------------------------------

### Column Calculation Example 3: Nested Addition

Source: https://mybatis-flex.com/zh/base/querywrapper.html

Shows how to perform nested addition operations on columns.

```java
QueryWrapper query = new QueryWrapper()
    .select(ACCOUNT.ID.add(ACCOUNT.AGE.add(100)).as("x100"))
    .from(ACCOUNT);

String sql = query.toSQL();
```

--------------------------------

### Maven Dependency for seata-spring-boot-starter

Source: https://mybatis-flex.com/zh/core/tx.html

Example Maven dependency for integrating seata-spring-boot-starter into a Spring Boot project.

```xml
<dependency>
    <groupId>io.seata</groupId>
    <artifactId>seata-spring-boot-starter</artifactId>
    <version>1.7.0</version>
</dependency>
```

--------------------------------

### ServiceImpl Generation Configuration

Source: https://mybatis-flex.com/zh/others/codegen.html

Example of configuring ServiceImpl generation, including setting class prefixes and suffixes, and superclass.

```java
globalConfig.getServiceImplConfig()
        .setClassPrefix("My")
        .setClassSuffix("ServiceImpl")
        .setSuperClass(ServiceImpl.class);
```

--------------------------------

### Service Generation Configuration

Source: https://mybatis-flex.com/zh/others/codegen.html

Example of configuring service generation, including setting class prefixes and suffixes, and superclass.

```java
globalConfig.getServiceConfig()
        .setClassPrefix("My")
        .setClassSuffix("Service")
        .setSuperClass(IService.class);
```

--------------------------------

### 实体类不在同一包下的辅助类生成

Source: https://mybatis-flex.com/zh/others/apt.html

当实体类不在同一包时，辅助类会在对应包下生成。如果启用了 `processor.allInTables.enable`，`Tables` 文件会生成在最后一个包中。推荐设置 `Tables` 文件的位置。

```properties
processor.allInTables.enable=true
processor.allInTables.package=com.example.entity.table
```

--------------------------------

### Seata Global Transactional Annotation

Source: https://mybatis-flex.com/zh/core/tx.html

Example of starting a Seata distributed transaction using the @GlobalTransactional annotation.

```java
import org.apache.ibatis.logging.Log;
import org.apache.ibatis.logging.LogFactory;
import com.seata.core.context.RootContext;
import com.seata.spring.annotation.GlobalTransactional;

public class PurchaseService {

    private static final Log LOGGER = LogFactory.getLog(PurchaseService.class);

    private StockClient stockClient;
    private OrderClient orderClient;

    @GlobalTransactional
    public void purchase(String userId, String commodityCode, int orderCount) {
        LOGGER.info("purchase begin ... xid: " + RootContext.getXID());
        stockClient.deduct(commodityCode, orderCount);
        orderClient.create(userId, commodityCode, orderCount);
    }
}
```

--------------------------------

### Using saveOpt for Callbacks

Source: https://mybatis-flex.com/zh/base/active-record.html

Example demonstrating the use of saveOpt() to get the saved entity with its ID after insertion, handling potential failures.

```java
// 插入成功之后返回主键信息
Account.create()
    .setUserName("张三")
    .setAge(18)
    .setBirthday(new Date())
    .saveOpt()
    .orElseThrow(RuntimeException::new) // 保存失败抛出异常
    .getId();
```

--------------------------------

### Maven 编译命令

Source: https://mybatis-flex.com/zh/others/apt.html

执行 maven 编译命令可以自动生成 APT 代码。

```bash
mvn clean package
```

--------------------------------

### 配置 MybatisFlexBootstrap

Source: https://mybatis-flex.com/zh/intro/use-in-kotlin.html

使用 DSL 和运算符重载快速配置 MybatisFlexBootstrap 实例。注意此方式不适用于 SpringBoot 环境。

```kotlin
    runFlex {
        // 配置数据源 相当于 setDataSource(dataSource)
        +dataSource
        // 配置Mapper 相当于 addMapper(AccountMapper::class.java)
        +AccountMapper::class
        // 配置日志输出 相当于 setLogImpl(StdOutImpl::class.java)
        logImpl = StdOutImpl::class
      }
```

--------------------------------

### limit... offset

Source: https://mybatis-flex.com/zh/base/querywrapper.html

Example of using limit and offset with QueryWrapper, with database-specific SQL examples.

```java
QueryWrapper queryWrapper = QueryWrapper.create()
    .select()
    .from(ACCOUNT)
    .orderBy(ACCOUNT.ID.desc())
    .limit(10)
    .offset(20);
```

--------------------------------

### Gradle 编译配置

Source: https://mybatis-flex.com/zh/others/apt.html

使用 Gradle 编译时，需要在 `dependencies` 中添加 `annotationProcessor` 配置。

```gradle
dependencies {
    ...
    annotationProcessor 'com.mybatis-flex:mybatis-flex-processor:1.11.7'
}
```

--------------------------------

### 使用 prepareAuth 实现数据权限

Source: https://mybatis-flex.com/zh/core/data-permission.html

通过重写 prepareAuth 方法处理 QueryWrapper 或 SQL 语句以添加权限条件。

```java
public class AuthDialectImpl extends CommonsDialectImpl {

    @Override
    public void prepareAuth(QueryWrapper queryWrapper, OperateType operateType) {
        List<QueryTable> queryTables = CPI.getQueryTables(queryWrapper);
        if (queryTables == null || queryTables.isEmpty()) {
            return;
        }
        for (QueryTable queryTable : queryTables) {
            if (PROJECT.getTableName().equals(queryTable.getName())) {
                queryWrapper.and(PROJECT.INSERT_USER_ID.eq(1));
            }
        }
        super.prepareAuth(queryWrapper, operateType);
    }

    @Override
    public void prepareAuth(String schema, String tableName, StringBuilder sql, OperateType operateType) {
        if (PROJECT.getTableName().equals(tableName)) {
            sql.append(AND).append(wrap("insert_user_id")).append(EQUALS).append(1);
        }
        super.prepareAuth(schema, tableName, sql, operateType);
    }

    @Override
    public void prepareAuth(TableInfo tableInfo, StringBuilder sql, OperateType operateType) {
        if (PROJECT.getTableName().equals(tableInfo.getTableName())) {
            sql.append(AND).append(wrap("insert_user_id")).append(EQUALS).append(1);
        }
        super.prepareAuth(tableInfo, sql, operateType);
    }
}
```

--------------------------------

### Complete Cacheable Methods Example

Source: https://mybatis-flex.com/zh/core/data-cache.html

Comprehensive example of AccountServiceImpl demonstrating various cacheable and cache-evicting methods.

```java
@Service
@CacheConfig(cacheNames = "account")
public class AccountServiceImpl extends CacheableServiceImpl<MyAccountMapper, Account> {

    @Override
    @CacheEvict(allEntries = true)
    public boolean remove(QueryWrapper query) {
        return super.remove(query);
    }

    @Override
    @CacheEvict(key = "#id")
    public boolean removeById(Serializable id) {
        return super.removeById(id);
    }

    @Override
    @CacheEvict(allEntries = true)
    public boolean removeByIds(Collection<? extends Serializable> ids) {
        return super.removeByIds(ids);
    }

    // 根据查询条件更新时，实体类主键可能为 null。
    @Override
    @CacheEvict(allEntries = true)
    public boolean update(Account entity, QueryWrapper query) {
        return super.update(entity, query);
    }

    @Override
    @CacheEvict(key = "#entity.id")
    public boolean updateById(Account entity, boolean ignoreNulls) {
        return super.updateById(entity, ignoreNulls);
    }

    @Override
    @CacheEvict(allEntries = true)
    public boolean updateBatch(Collection<Account> entities, int batchSize) {
        return super.updateBatch(entities, batchSize);
    }

    @Override
    @Cacheable(key = "#id")
    public Account getById(Serializable id) {
        return super.getById(id);
    }

    @Override
    @Cacheable(key = "#root.methodName + ':' + #query.toSQL()")
    public Account getOne(QueryWrapper query) {
        return super.getOne(query);
    }

    @Override
    @Cacheable(key = "#root.methodName + ':' + #query.toSQL()")
    public <R> R getOneAs(QueryWrapper query, Class<R> asType) {
        return super.getOneAs(query, asType);
    }

    @Override
    @Cacheable(key = "#root.methodName + ':' + #query.toSQL()")
    public List<Account> list(QueryWrapper query) {
        return super.list(query);
    }

    @Override
    @Cacheable(key = "#root.methodName + ':' + #query.toSQL()")
    public <R> List<R> listAs(QueryWrapper query, Class<R> asType) {
        return super.listAs(query, asType);
    }

    // 无法通过注解进行缓存操作
    @Override
    @Deprecated
    public List<Account> listByIds(Collection<? extends Serializable> ids) {
        return super.listByIds(ids);
    }

    @Override
    @Cacheable(key = "#root.methodName + ':' + #query.toSQL()")
    public long count(QueryWrapper query) {
        return super.count(query);
    }

    @Override
    @Cacheable(key = "#root.methodName + ':' + #page.getPageSize() + ':' + #page.getPageNumber() + ':' + #query.toSQL()")
    public <R> Page<R> pageAs(Page<R> page, QueryWrapper query, Class<R> asType) {
        return super.pageAs(page, query, asType);
    }

}
```

--------------------------------

### 配置大字段标识

Source: https://mybatis-flex.com/zh/core/column.html

使用 isLarge 属性标记大字段，使其在 APT 生成的 DEFAULT_COLUMNS 中被排除，优化查询性能。

```java
@Table("tb_article")
public class Article {

    @Id(keyType = KeyType.Auto)
    private Long id;

    private String title;

    @Column(isLarge = true)
    private String content;

    @Column(onInsertValue = "now()")
    private Date created;

    @Column(onUpdateValue = "now()", onInsertValue = "now()")
    private Date modified;
}
```

```java
public class Tables {
    public static final ArticleTableDef ARTICLE = new ArticleTableDef("tb_article");

    public static class ArticleTableDef extends TableDef {

        public QueryColumn ID = new QueryColumn(this, "id");
        public QueryColumn TITLE = new QueryColumn(this, "title");
        public QueryColumn CONTENT = new QueryColumn(this, "content");
        public QueryColumn CREATED = new QueryColumn(this, "created");
        public QueryColumn MODIFIED = new QueryColumn(this, "modified");

        //在 DEFAULT_COLUMNS 中是没有 content 字段。
        public QueryColumn[] DEFAULT_COLUMNS = new QueryColumn[]{ID, TITLE, CREATED, MODIFIED};
        public QueryColumn ALL_COLUMNS = new QueryColumn("*");
    }
}
```

```java
QueryWrapper.create()
    .select(ARTICLE.DEFAULT_COLUMNS) //使用的是 DEFAULT_COLUMNS
    .from(ARTICLE);
```

--------------------------------

### Entity Superclass Factory Example

Source: https://mybatis-flex.com/zh/others/codegen.html

Example demonstrating the use of setEntitySuperClassFactory to dynamically set the superclass for entities based on the table.

```java
globalConfig.setEntitySuperClassFactory(table -> {

    // 在这里，可以通过 table 来指定对应 SuperClass
    // 返回 null，则表示不需要设置父类
    return null;
});
```

--------------------------------

### 自定义 APT 代码生成路径

Source: https://mybatis-flex.com/zh/others/apt.html

配置 `processor.genPath` 来自定义 APT 代码生成路径。

```properties
processor.genPath=your-path
```

--------------------------------

### Code Generator Cannot Get Comments

Source: https://mybatis-flex.com/zh/faq.html

For MySQL databases, if the database version is too low, you might not get comments. To resolve this, add the parameter 'useInformationSchema=true' to the jdbcUrl. For Oracle, add 'remarksReporting=true'.

```string
jdbc:mysql://127.0.0.1:3306/mybatis-flex?characterEncoding=UTF-8&useInformationSchema=true
```

```string
jdbc:oracle:thin:@localhost:1521:orcl?remarksReporting=true
```

--------------------------------

### Implement MyBatisFlexCustomizer for Initialization

Source: https://mybatis-flex.com/zh/base/mybatis-flex-customizer.html

Implement the MyBatisFlexCustomizer interface in a @Configuration class to perform initialization configurations for MyBatis-Flex. This is useful for setting up global configurations, custom primary key generators, multi-tenancy, dynamic table names, and more.

```java
import org.springframework.context.annotation.Configuration;
import com.mybatisflex.core.config.FlexGlobalConfig;
import com.mybatisflex.core.mybatis.MyBatisFlexCustomizer;

@Configuration
public class MyBatisFlexConfiguration implements MyBatisFlexCustomizer {

    @Override
    public void customize(FlexGlobalConfig globalConfig) {
        // We can perform a series of initialization configurations here
    }

}
```

--------------------------------

### Db.tx() Code Example

Source: https://mybatis-flex.com/zh/core/tx.html

This example demonstrates the basic usage of the Db.tx() method. The provided Supplier contains the transactional operations. If the Supplier returns true, the transaction is committed; otherwise (if it returns null, false, or throws an exception), the transaction is rolled back.

```java
Db.tx(() -> {

    //进行事务操作

    return true;
});
```

--------------------------------

### join self

Source: https://mybatis-flex.com/zh/base/querywrapper.html

Example of joining a table to itself using QueryWrapper.

```java
AccountTableDef a1 = ACCOUNT.as("a1");
AccountTableDef a2 = ACCOUNT.as("a2");
ArticleTableDef ar = ARTICLE.as("ar");

QueryWrapper queryWrapper = new QueryWrapper()
    .select(ar.CONTENT, a1.ID, a2.AGE)
    .from(ar)
    .leftJoin(a1).on(a1.ID.eq(ar.ACCOUNT_ID))
    .leftJoin(a2).on(a2.ID.eq(ar.ACCOUNT_ID));
```

--------------------------------

### Using SQL Hints

Source: https://mybatis-flex.com/zh/base/querywrapper.html

Explains and demonstrates the use of SQL hints (e.g., `INDEX_DESC`) to influence query execution plans.

```java
QueryWrapper queryWrapper=QueryWrapper.create()
    .select().hint("INDEX_DESC")
    .from(ACCOUNT)
    .orderBy(ACCOUNT.AGE.asc(), ACCOUNT.USER_NAME.desc().nullsLast());
```

--------------------------------

### APT 开启 Mapper 生成

Source: https://mybatis-flex.com/zh/others/apt.html

配置 `processor.mapper.generateEnable=true` 来开启 Mapper 的自动生成功能。

```properties
processor.mapper.generateEnable=true
```

--------------------------------

### join select

Source: https://mybatis-flex.com/zh/base/querywrapper.html

Example of joining with a subquery using QueryWrapper.

```java
QueryWrapper queryWrapper = QueryWrapper.create()
    .select()
    .from(ACCOUNT)
    .leftJoin(
        select().from(ARTICLE).where(ARTICLE.ID.ge(100))
    ).as("a").on(
        ACCOUNT.ID.eq(raw("a.id"))
    )
    .where(ACCOUNT.AGE.ge(10));
```

--------------------------------

### 自定义 TableDef 字段风格

Source: https://mybatis-flex.com/zh/others/apt.html

配置 `processor.tableDef.propertiesNameStyle` 来修改 TableDef 生成的字段风格。

```properties
#upperCase, lowerCase, upperCamelCase, lowerCamelCase
processor.tableDef.propertiesNameStyle=upperCase
```

--------------------------------

### 自定义 Tables 类名和包名

Source: https://mybatis-flex.com/zh/others/apt.html

配置 `processor.allInTables.enable`、`processor.allInTables.package`、`processor.allInTables.className` 来自定义生成的 Tables 类名和包名。

```properties
processor.allInTables.enable=true
processor.allInTables.package=com.your-package
processor.allInTables.className=your-class-name
```

--------------------------------

### Nested Transaction Example

Source: https://mybatis-flex.com/zh/core/tx.html

This example illustrates how to implement nested transactions using Db.tx(). The outer Db.tx() call wraps an inner Db.tx() call. By default, nested transactions behave like the REQUIRED propagation, meaning they join an existing transaction if one is present, or create a new one if not.

```java
Db.tx(() -> {

    //进行事务操作

    boolean success = Db.tx(() -> {
        //另一个事务的操作
        return true;
    });


    return true;
});
```

--------------------------------

### Spring Boot 配置注册方言

Source: https://mybatis-flex.com/zh/core/data-permission.html

在 Spring Boot 项目中通过 MyBatisFlexCustomizer 注册方言。

```java
@Configuration
public class MybatisFlexConfig implements MyBatisFlexCustomizer {

    @Override
    public void customize(FlexGlobalConfig flexGlobalConfig) {
        

        // 注册查询权限监听方言
        DialectFactory.registerDialect(DbType.MYSQL, new AuthDialectImpl());
    }
}
```

--------------------------------

### Cursor Query Example

Source: https://mybatis-flex.com/zh/base/query.html

For processing large datasets, use cursor queries to prevent memory leaks. This example demonstrates fetching accounts using a cursor within a transaction. Cursor queries fetch data one record at a time during iteration, and must be executed within a transaction to maintain the database connection.

```java
Cursor<T> selectCursorByQuery(QueryWrapper queryWrapper);
```

```java
Db.tx(() -> {
    Cursor<Account> accounts = accountMapper.selectCursorByQuery(query);
    for (Account account : accounts) {
        System.out.println(account);
    }
    return true;
});
```

--------------------------------

### Inserting an Article

Source: https://mybatis-flex.com/zh/core/multi-tenancy.html

Example of inserting an Article, demonstrating how tenantId is handled.

```java
Article article = new Article();
article.setTenantId(100);

articleMapper.insert(article);
```

--------------------------------

### 配置数据源解密器

Source: https://mybatis-flex.com/zh/core/datasource-encryption.html

通过 DataSourceManager 设置解密逻辑，必须在 MybatisFlexBootstrap 初始化之前调用。

```java
DruidDataSource dataSource = new DruidDataSource();
dataSource.setUrl("jdbc:mysql://localhost:3306/flex_test");
dataSource.setUsername("root123"); // 真实的账号应该是 root
dataSource.setPassword("123456---0000"); // 真实的密码应该是 123456
        
//配置数据源解密器：DataSourceDecipher
DataSourceManager.setDecipher(new DataSourceDecipher() {
    @Override
    public String decrypt(DataSourceProperty property, String value) {
        //解密用户名，通过编码支持任意加密方式的解密
        if (property == DataSourceProperty.USERNAME) {
            return value.substring(0, 4);
        } 
        //解密密码
        else if (property == DataSourceProperty.PASSWORD) {
            return value.substring(0, 6);
        }
        return value;
    }
});
        
MybatisFlexBootstrap.getInstance()
        .setDataSource(dataSource)
        .addMapper(TenantAccountMapper.class)
        .start();

List<Row> rowList = Db.selectAll("tb_account");
RowUtil.printPretty(rowList);
```

--------------------------------

### MyBatis-Plus Data Update

Source: https://mybatis-flex.com/zh/intro/benchmark.html

Example of updating data using MyBatis-Plus.

```java
PlusAccount plusAccount = new PlusAccount();
plusAccount.setUserName("testInsert" + i);
plusAccount.setNickname("testInsert" + i);
plusAccount.addOption("key1", "value1");
plusAccount.addOption("key2", "value2");
plusAccount.addOption("key3", "value3");
plusAccount.addOption("key4", "value4");
plusAccount.addOption("key5", "value5");

LambdaUpdateWrapper<PlusAccount> updateWrapper = new LambdaUpdateWrapper<>();
updateWrapper.ge(PlusAccount::getId, 9000);
updateWrapper.le(PlusAccount::getId, 9100);
updateWrapper.like(PlusAccount::getUserName, "admin");
updateWrapper.like(PlusAccount::getNickname, "admin");

mapper.update(plusAccount, lambdaUpdateWrapper);
```

--------------------------------

### MyBatis-Flex Data Update

Source: https://mybatis-flex.com/zh/intro/benchmark.html

Example of updating data using MyBatis-Flex.

```java
FlexAccount flexAccount = new FlexAccount();
flexAccount.setUserName("testInsert" + i);
flexAccount.setNickname("testInsert" + i);
flexAccount.addOption("key1", "value1");
flexAccount.addOption("key2", "value2");
flexAccount.addOption("key3", "value3");
flexAccount.addOption("key4", "value4");
flexAccount.addOption("key5", "value5");

QueryWrapper queryWrapper = QueryWrapper.create()
    .where(FLEX_ACCOUNT.ID.ge(9200))
    .and(FLEX_ACCOUNT.ID.le(9300))
    .and(FLEX_ACCOUNT.USER_NAME.like("admin"))
    .and(FLEX_ACCOUNT.NICKNAME.like("admin"));

mapper.updateByQuery(flexAccount, queryWrapper);
```

--------------------------------

### APT 过滤 Entity 后缀

Source: https://mybatis-flex.com/zh/others/apt.html

配置 `processor.tableDef.ignoreEntitySuffixes` 来过滤 Entity 的通用后缀。

```properties
processor.tableDef.ignoreEntitySuffixes=Model, Dto
```

--------------------------------

### MyBatis-Flex YAML Configuration

Source: https://mybatis-flex.com/zh/base/configuration.html

Example of MyBatis-Flex configuration in a SpringBoot or Solon application's YAML file. This section covers various aspects like data sources, global configurations, and admin settings.

```yaml
mybatis-flex:
  #......
  datasource:
    #......
  configuration:
    #......
  global-config:
    #......
  admin-config:
    #......
  seata-config:
    #......
```

--------------------------------

### Advanced UpdateWrapper Usage

Source: https://mybatis-flex.com/zh/base/add-delete-update.html

Advanced examples of using UpdateWrapper for complex field updates.

```java
Account account = UpdateEntity.of(Account.class, 100);

account.setUserName("Michael");

// 通过 UpdateWrapper 操作 account 数据
UpdateWrapper wrapper = UpdateWrapper.of(account);
wrapper.set(ACCOUNT.AGE, ACCOUNT.AGE.add(1));

accountMapper.update(account);
```

```sql
update tb_account
set user_name = "michael", age = age + 1 where id = 100
```

```java
Account account = UpdateEntity.of(Account.class, 100);

account.setUserName("Michael");

// 通过 UpdateWrapper 操作 account 数据
UpdateWrapper wrapper = UpdateWrapper.of(account);
wrapper.set(ACCOUNT.AGE, select().from(...));

accountMapper.update(account);
```

```sql
update tb_account
set user_name = "michael", age = (select ... from ... )
where id = 100
```

--------------------------------

### 自定义 Mapper 父类

Source: https://mybatis-flex.com/zh/others/apt.html

配置 `processor.mapper.baseClass` 来自定义 Mapper 的父类。

```properties
processor.mapper.baseClass=com.domain.mapper.MyBaseMapper
```

--------------------------------

### Multi-Datasource Transaction Example

Source: https://mybatis-flex.com/zh/core/tx.html

This example shows how multiple data sources can be managed within a single @Transactional annotation. Even though operations are performed on different data sources (ds1 and ds2), they are part of the same transaction. If an exception occurs (like division by zero), all operations within that transaction will be rolled back.

```java
@Transactional
public void doSomething(){

    try{
        DataSourceKey.use("ds1");
        Db.updateBySql("update .... ");
    }finally{
        DataSourceKey.clear()
    }

    try{
        DataSourceKey.use("ds2");
        Db.updateBySql("update ...");
    }finally{
        DataSourceKey.clear();
    }

    //抛出异常
    int x = 1/0;
}
```

--------------------------------

### join on multiple conditions

Source: https://mybatis-flex.com/zh/base/querywrapper.html

Example of joining with multiple conditions using QueryWrapper.

```java
QueryWrapper queryWrapper = QueryWrapper.create()
    .select()
    .from(ACCOUNT)
    .leftJoin(ARTICLE).on(
        ACCOUNT.ID.eq(ARTICLE.ACCOUNT_ID).and(ACCOUNT.AGE.eq(18))
    )
    .where(ACCOUNT.AGE.ge(10));
```

--------------------------------

### Excluding SpringDataWebAutoConfiguration

Source: https://mybatis-flex.com/zh/faq.html

Example of excluding SpringDataWebAutoConfiguration to resolve warnings with spring-data integration.

```java
@SpringBootApplication(exclude = SpringDataWebAutoConfiguration.class)
public class SampleApplication {}
```

--------------------------------

### 默认 TableDef 生成

Source: https://mybatis-flex.com/zh/others/apt.html

默认情况下 APT 生成的 TableDef 内容示例。

```java
public class AccountTableDef extends TableDef {

    public static final AccountTableDef ACCOUNT = new AccountTableDef("", "tb_account");

    public QueryColumn ID = new QueryColumn(this, "id");
    public QueryColumn USER_NAME = new QueryColumn(this, "user_name");

    public QueryColumn ALL_COLUMNS = new QueryColumn(this, "*");
    public QueryColumn[] DEFAULT_COLUMNS = new QueryColumn[]{ID, USER_NAME};

    public AccountTableDef(String schema, String tableName) {
        super(schema, tableName);
    }

}
```

--------------------------------

### Gradle 插件应用 (Kotlin)

Source: https://mybatis-flex.com/zh/others/kapt.html

在 Gradle 项目中应用 kotlin-kapt 插件，并注意版本一致性。

```kotlin
plugins {
    // 如果正在使用 SpringBoot，请保持 kapt 插件版本与 Spring 插件、kotlin JVM 插件一致
    // 如你的插件版本是（如果项目是使用 Spring Initializr 生成的话，是会自带下面两个插件）： 
    // kotlin("jvm") version "1.9.20" <- 注意版本
    // kotlin("plugin.spring") version "1.9.20" <- 注意版本
    // 那么你的 kapt 版本也需要与其一致，否则将会改变项目使用的 Kotlin 版本，可能会引发兼容性问题
    kotlin("kapt") version "1.9.20"
}
```

--------------------------------

### Multi-Table Query 1 (Fluent-MyBatis)

Source: https://mybatis-flex.com/zh/intro/comparison.html

Example of a join query using Fluent-MyBatis.

```java
StudentQuery leftQuery = new StudentQuery("a1").selectAll()
    .where.age().eq(34)
    .end();
HomeAddressQuery rightQuery = new HomeAddressQuery("a2")
    .where.address().like("address")
    .end();

IQuery query = leftQuery
    .join(rightQuery)
    .on(l -> l.where.homeAddressId(), r -> r.where.id()).endJoin()
    .build();

List<StudentEntity> entities = this.mapper.listEntity(query);
```

--------------------------------

### Gradle 插件应用 (Groovy)

Source: https://mybatis-flex.com/zh/others/kapt.html

在 Gradle 项目中应用 kotlin-kapt 插件（Groovy 语法）。

```groovy
plugins {
    id 'org.jetbrains.kotlin.kapt' version '1.9.20'
}
```

--------------------------------

### MyBatis-Plus Pagination Query

Source: https://mybatis-flex.com/zh/intro/benchmark.html

Example of how to perform a paginated query using MyBatis-Plus.

```java
LambdaQueryWrapper<PlusAccount> queryWrapper = new LambdaQueryWrapper<>();
    queryWrapper.ge(PlusAccount::getId, 100);
    queryWrapper.eq(PlusAccount::getEmail, "michael@gmail.com");
    Page<PlusAccount> p = Page.of(page, pageSize, 20000, false);
    mapper.selectPage(p, queryWrapper);
```

--------------------------------

### 示例配置

Source: https://mybatis-flex.com/zh/others/apt.html

展示了如何使用包名表达式 `${entityPackage}`、`${entityPackage.parent}`、`${entityPackage.parent.parent}` 来配置包名。

```properties
processor.allInTables.package=${entityPackage}.table
processor.mapper.package=${entityPackage.parent}.mapper
processor.tableDef.package=${entityPackage.parent.parent}.table
```

--------------------------------

### MyBatis-Flex Pagination Query

Source: https://mybatis-flex.com/zh/intro/benchmark.html

Example of how to perform a paginated query using MyBatis-Flex.

```java
QueryWrapper queryWrapper = new QueryWrapper()
    .where(FLEX_ACCOUNT.ID.ge(100));
mapper.paginate(page, pageSize, 20000, queryWrapper);
```

--------------------------------

### Partial Field Update (Fluent-MyBatis)

Source: https://mybatis-flex.com/zh/intro/comparison.html

Example of updating specific fields using Fluent-MyBatis.

```java
AccountUpdate update = new AccountUpdate()
.update.userName().is("michael")
.age().is(18)
.birthday().is(null)
.end()
.where.id().eq(100)
.end();
accountMapper.updateBy(update);
```

--------------------------------

### Gradle 依赖添加 (Kotlin)

Source: https://mybatis-flex.com/zh/others/kapt.html

在 Gradle 项目的 dependencies 块中添加 mybatis-flex-processor 依赖，并使用 kapt 配置。

```kotlin
dependencies {
    kapt("com.mybatis-flex:mybatis-flex-processor:1.5.6")
}
```

--------------------------------

### Multi-Table Query 2 (MyBatis-Flex)

Source: https://mybatis-flex.com/zh/intro/comparison.html

Example of a multi-table query with aliases using MyBatis-Flex.

```java
QueryWrapper 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));
```

--------------------------------

### Enable MyBatis-Flex-Admin Logging

Source: https://mybatis-flex.com/zh/base/configuration.html

Configuration to enable and set up the connection to MyBatis-Flex-Admin for SQL auditing. Ensure the secret-key matches the one configured in the MyBatis-Flex-Admin project.

```yaml
mybatis-flex:
  admin-config:
    enable: true
    endpoint: http://admin-host:8080/message/collect
    secret-key: secretKey
```

--------------------------------

### Multi-Table Query 1 (MyBatis-Flex)

Source: https://mybatis-flex.com/zh/intro/comparison.html

Example of a left join query using MyBatis-Flex.

```java
QueryWrapper query = QueryWrapper.create()
    .select().from(ACCOUNT)
    .leftJoin(ARTICLE).on(ACCOUNT.ID.eq(ARTICLE.ACCOUNT_ID))
    .where(ACCOUNT.AGE.ge(10));

List<Account> accounts = mapper.selectListByQuery(query);
```

--------------------------------

### Paginated Query with Db + Row in Java

Source: https://mybatis-flex.com/zh/base/db-row.html

Illustrates how to perform paginated queries using QueryWrapper and the Db tool, specifying table, page number, page size, and query conditions.

```java
QueryWrapper query=QueryWrapper.create()
    .where(ACCOUNT.AGE.ge(18));
Page<Row> rowPage=Db.paginate("tb_account",3,10,query);
```