java - Spring Data JDBC @Modifying 与 PostgreSQL RETURNING 从修改的行返回数据

Question

PostgreSQL 提供了一种从 DML 语句返回数据的简洁方法，请参阅 https://www.postgresql.org/docs/current/dml-returning.html

我试图实现的目标类似于下面的片段

@Modifying
@Query("DELETE FROM Book b WHERE b.title = :title RETURNING *")
Book deleteReturning(@Param("title") String title);

检索已删除的行。 但是，这会导致以下异常

org.springframework.dao.DataIntegrityViolationException: PreparedStatementCallback; SQL [DELETE FROM Book b WHERE b.title = ? RETURNING *]; A result was returned when none was expected.; nested exception is org.postgresql.util.PSQLException: A result was returned when none was expected.
    at org.springframework.jdbc.support.SQLStateSQLExceptionTranslator.doTranslate(SQLStateSQLExceptionTranslator.java:104)
    at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:72)
    at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:81)
    at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:81)
    at org.springframework.jdbc.core.JdbcTemplate.translateException(JdbcTemplate.java:1443)
    at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:633)
    at org.springframework.jdbc.core.JdbcTemplate.update(JdbcTemplate.java:862)
    at org.springframework.jdbc.core.JdbcTemplate.update(JdbcTemplate.java:883)
    at org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate.update(NamedParameterJdbcTemplate.java:321)
    at org.springframework.data.jdbc.repository.query.AbstractJdbcQuery.lambda$createModifyingQueryExecutor$0(AbstractJdbcQuery.java:103)
    at org.springframework.data.jdbc.repository.query.StringBasedJdbcQuery.execute(StringBasedJdbcQuery.java:85)
    at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor$QueryMethodInvoker.invoke(QueryExecutorMethodInterceptor.java:195)
    at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.doInvoke(QueryExecutorMethodInterceptor.java:152)
    at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.invoke(QueryExecutorMethodInterceptor.java:130)
    ...
Caused by: org.postgresql.util.PSQLException: A result was returned when none was expected.
    at org.postgresql.jdbc.PgStatement.checkNoResultUpdate(PgStatement.java:269)
    at org.postgresql.jdbc.PgPreparedStatement.executeUpdate(PgPreparedStatement.java:131)
    at com.zaxxer.hikari.pool.ProxyPreparedStatement.executeUpdate(ProxyPreparedStatement.java:61)
    at com.zaxxer.hikari.pool.HikariProxyPreparedStatement.executeUpdate(HikariProxyPreparedStatement.java)
    at org.springframework.jdbc.core.JdbcTemplate.lambda$update$0(JdbcTemplate.java:867)
    at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:617)
    ... 95 more

Spring Data JDBC 规定修改查询只能返回 void、int 和 boolean，请参阅 https://docs.spring.io/spring-data/jdbc/docs/current/reference/html/#jdbc.query-methods.at-query.modifying

添加自定义 RowMapper 会导致相同的异常。

    public class BookRowMapper<T> implements RowMapper<Book> {
        @Override
        public Book mapRow(final ResultSet rs, final int rowNum) throws SQLException {
            return new Book(rs.getString(1), ...);
        }
    }

    @Modifying
    @Query(value = "delete from Book b where b.title = :title returning *", rowMapperClass = BookRowMapper.class)
    Book deleteReturning(@Param("title") String title);

是否有办法实现这一目标？

编辑:我知道普通的 JDBC https://stackoverflow.com/a/40787385/1239904但我想采用 Spring 方式。

Answer 1

当您使用@Modifying注释该方法时，它将作为DML语句执行，除了更新的行数之外不返回任何值。

如果您的语句返回 ResultSet，则不应使用 @Modifying，因此 Spring Data JDBC 会尝试提取 ResultSet 并创建返回值获取其中的方法。