Spring Data JDBC @Modifying with PostgreSQL RETURNING从修改后的行返回数据

编程问答 2022-06-04

问题描述

Postgresql提供了一种从DML语句返回数据的巧妙方法，请参见https://www.postgresql.org/docs/current/dml-returning.html

我试图实现的目标类似于以下内容

@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指出，修改后的查询只能返回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);

是否可以实现这一目标？

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

解决方法

使用@Modifying注释该方法时，该方法将作为DML语句执行，该语句不返回任何值，但更新的行数除外。

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并从中创建方法的返回值。

javajavapostgresqlspring-data-jdbc