# drawdb-server

**Repository Path**: zhengxingne/drawdb-server

## Basic Information

- **Project Name**: drawdb-server
- **Description**: sql编辑器后端服务
- **Primary Language**: Unknown
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 1
- **Forks**: 0
- **Created**: 2024-04-30
- **Last Updated**: 2024-09-22

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

```java
// Mapper继承MPJBaseMapper才能使用Join
MPJLambdaWrapper<DtHistoryRecord> mapper=new MPJLambdaWrapper<DtHistoryRecord>()

// 展示实体类全部字段
.selectAll(DtHistoryRecord.class)

// 展示自定义字段
.select(DtHistoryRecord::getId,DtHistoryRecord::getProjectId)

// 设置字段别名
.selectAs(User::getName, UserDTO::getNickname)

// 展示自定义字段
.select("t.id as twinId","t1.value as twinName")

// 表连接需要被连接的库XEasyDtProject, XEasyDtProject::getId必须作为第一个，连接 DtHistoryRecord::getProjectId
.leftJoin(XEasyDtProject.class,XEasyDtProject::getId,DtHistoryRecord::getProjectId)

// 把数据集合到DtHistoryRecordResponse::getXEasyDtProject当前实体类的字段中,XEasyDtProject被封装的实体类
.selectAssociation(XEasyDtProject.class,DtHistoryRecordResponse::getXEasyDtProject);

// 封装到list集合类中
.selectCollection(XEasyDtProject.class,DtHistoryRecordResponse::getXEasyDtProject)

// 根据实体类把查询的数据进行封装
dtHistoryRecordMapper.selectJoinList(DtHistoryRecordResponse.class,mapper);
```

```java
MPJLambdaWrapper<DtTwinClassify> query = new MPJLambdaWrapper<DtTwinClassify>()
    // 查询字段
    .selectAll(DtTwinClassify.class);

    // DtTwinDefinition 集合的对象必须是实体类的对象否则无法使用 
    .selectCollection(DtTwinDefinition.class,TwinTreeDataResponse::getList,a->a
    .collection(DtTwinExample.class,DtTwinDefinitionTreeResponse::getList,b->b
    .collection(DtTwinExampleData.class,DtTwinExampleTreeResponse::getList)))
    
    // 连接方式前一个必须是连接的实体类
    .leftJoin(DtTwinDefinition.class,DtTwinDefinition::getDirectoryId,DtTwinClassify::getId)
    .leftJoin(DtTwinExample.class,DtTwinExample::getDefinitionId,DtTwinDefinition::getId)
    .leftJoin(DtTwinExampleData.class,DtTwinExampleData::getParentId,DtTwinExample::getId)
    
    // 查询条件
    .eq(DtTwinExample::getId,twinId);

    List<TwinTreeDataResponse> twinTreeDataResponses=
    dtTwinClassifyMapper.selectJoinList(TwinTreeDataResponse.class,query);
```

```java
// 分页查询
IPage<UserDTO> page = userMapper.selectJoinPage(new Page<>(1, 10), UserDTO.class,
        new MPJLambdaWrapper<>()
                .selectAll(UserDO.class)
                .select(UserAddressDO::getAddress)
                .leftJoin(UserAddressDO.class, UserAddressDO::getUserId, UserDO::getId)
                .eq(UserDO::getId, 1));
```