Hibernate查询oracle数据库char类型字段,获取不到结果的问题
作者:互联网
问题分析:
1)去掉按月份搜索的条件是可以的查询到数据。
2)拼接sql的形式是可以查询到信息的数据。
3)用其他Varchar2类型的字段动态绑定参数查询是可以的。
/** * YM 在数据库为char类型,字符长度为8,而字段为年月 例如:202101,而要和数据库中char类型的长度一致,长度不够的,用空格补齐。 */ if (StringUtils.isNotEmpty(ym)) { sql += " and mapp.YM=:YM"; params.put("YM", ym); }
结论:该问题可能和字段类型和hibernate的动态绑定有关系。
查询材料解释:
https://community.oracle.com/tech/developers/discussion/comment/506702#Comment_506702
Select * From table Where column = ? setObject(1, "compValue") will never return anything if the type of column would be e.g. CHAR(20) This behaviour is inconsistent to executing the same select as statement in the following form Statement.executeQuery(Select * From table Where column = "compValue") which will return all rows, where the value matches. The difference in the behaviour lies in the fact, that for a PreparedStatment the number of characters must match. ================================================================================== use setFixedCHAR(....)., quote from Oracle9i JDBC API Docs public void setFixedCHAR(int paramIndex, java.lang.String x) throws java.sql.SQLException Sets the disignated parameter to a String and executes a non-padded comparison with a SQL CHAR. CHAR data in the database is padded to the column width. This leads to a limitation in using the setCHAR() method to bind character data into the WHERE clause of a SELECT statement--the character data in the WHERE clause must also be padded to the column width to produce a match in the SELECT statement. This is especially troublesome if you do not know the column width. setFixedCHAR() remedies this. This method executes a non-padded comparison.
大体意思就是说采用CHAR类型,是固定类型,如果长度不够会用空格补齐,因此采用PreparedStatement动态参数绑定查询时,要采用 OraclePreparedStatement 的setFixedCHAR() 设置char类型的字段。
解决办法:
Hibernate底层是基于PrepardStatement的,但是设置参数是没办法指定setFixedCHAR(),常用的时采用如下方式 query.setParameter(key, map.get(key)); 因此使用setFixedCHAR()的方式行不太通。
1)将字段trim化,去除空格(不推荐,如果在该字段上有索引的化,索引会不起作用)。
if (StringUtils.isNotEmpty(ym)) { sql += " and trim(mapp.YM)=:YM"; params.put("YM", ym); }
2)将字段类型改为varchar2类型 (项目中使用,推荐使用)。
标签:padded,Hibernate,YM,setFixedCHAR,column,查询,char,类型,oracle 来源: https://blog.csdn.net/fred_kang/article/details/112519970