84 lines
3.8 KiB
Markdown
84 lines
3.8 KiB
Markdown
# DataSqlSource数据源
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  ```DataSqlSource```是```DataSource```的SQL扩展类，增强了对原生SQL的操作。
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## SQL模板
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  Redkale中的SQL模板与Mybatis里的SQL模板用法类似， 最大区别在于不需要写很多```if/else```判断语句,也不用写xml文件， 框架会根据参数存在与否动态生成sql语句， 查询结果时带下划线的sql字段名和类中的驼峰字段名会自动匹配。
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```sql
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SELECT * FROM user WHERE user_id IN ${bean.userIds} OR user_name = ${bean.userName}
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```
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  当bean.userIds=null，bean.userName='hello'时，sql语句转换成
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```sql
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SELECT * FROM user WHERE user_name = 'hello'
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```
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  当bean.userIds=[1,2,3]，bean.userName=null时，sql语句转换成
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```sql
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SELECT * FROM user WHERE user_id IN (1,2,3)
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```
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  IN或者NOT IN语句当参数不为null而是空数组或者空List会进行特殊处理，IN语句会转化成```1=1```, NOT IN语句会转化成```1=2```。 当bean.userIds=空数组，bean.userName='hello'时，sql语句转换成
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```sql
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SELECT * FROM user WHERE 1=2 OR user_name = 'hello'
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```
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  有些场景要求参数是必需的，就需要使用$${}来校验参数是否必需。
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```sql
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DELETE FROM user WHERE user_name = $${bean.userName}
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```
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  当bean.userName=null时，执行sql会报错 ```Missing parameter bean.userName```
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  Service调用原生SQL模板示例：
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```java
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public class ForumInfoService extends AbstractService {
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//查询单个记录的sql
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private static final String findOneSql = "SELECT f.forum_groupid, s.forum_section_color "
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+ "FROM forum_info f, forum_section s "
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+ " WHERE f.forumid = s.forumid AND "
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+ "s.forum_sectionid = ${bean.forumSectionid} AND "
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+ "f.forumid = ${bean.forumid} AND s.forum_section_color = ${bean.forumSectionColor}";
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//查询列表记录的sql
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private static final String queryListSql = "SELECT f.forum_groupid, s.forum_section_color "
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+ "FROM forum_info f, forum_section s "
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+ " WHERE f.forumid = s.forumid AND "
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+ "s.forum_sectionid = ${bean.forumSectionid} AND "
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+ "f.forumid = ${bean.forumid} AND s.forum_section_color = ${bean.forumSectionColor}";
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@Resource
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private DataSqlSource source;
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public ForumResult findForumResultOne(ForumBean bean) {
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return source.nativeQueryOne(ForumResult.class, findOneSql, Map.of("bean", bean));
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}
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public CompletableFuture<List<ForumResult>> queryForumResultListAsync(ForumBean bean) {
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return source.nativeQueryListAsync(ForumResult.class, queryListSql, Map.of("bean", bean));
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}
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}
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```
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## DataSqlMapper
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  DataSqlMapper与MyBatis里的Mapper用法类似。
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```java
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public interface ForumInfoMapper extends BaseMapper<ForumInfo> {
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@Sql("SELECT f.forum_groupid, s.forum_section_color "
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+ "FROM forum_info f, forum_section s "
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+ "WHERE f.forumid = s.forumid "
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+ "AND s.forum_sectionid = ${bean.forumSectionid} "
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+ "AND f.forumid = ${bean.forumid} "
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+ "AND s.forum_section_color = ${bean.forumSectionColor}")
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public ForumResult findForumResultOne(ForumBean bean);
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@Sql("SELECT f.forum_groupid, s.forum_section_color "
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+ "FROM forum_info f, forum_section s "
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+ "WHERE f.forumid = s.forumid AND "
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+ "s.forum_sectionid = ${bean.forumSectionid} "
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+ "AND f.forumid = ${bean.forumid} "
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+ "AND s.forum_section_color = ${bean.forumSectionColor}")
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public CompletableFuture<ForumResult> findForumResultOneAsync(ForumBean bean);
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@Sql("UPDATE forum_section s "
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+ " SET s.forum_sectionid = '' "
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+ " WHERE s.forum_section_color = $${bean.forumSectionColor}")
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public int updateForumResult(@Param("bean") ForumBean bean0);
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}
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``` |