Question

我想使用JPA调用Oracle函数。我在这个主题上找到了this thread。

但是我的Oracle函数只返回一个字符串。不是某种实体的结果。我试过这样的事情：

@NamedNativeQuery(name = "myFuncCall",
        resultSetMapping = "myResultSetMapping",
        query = "{ ? = call schema.mypkg.somefunc(:id) }",
        hints = { @javax.persistence.QueryHint(name = "org.hibernate.callable", value = "true") }
)

@SqlResultSetMapping(name = "myResultSetMapping",
    columns = { @ColumnResult(name="somename") }
)

当我像这样调用查询时

Query query = em.createNamedQuery("myFuncCall", String.class).setParameter("id", "42");
        String res = (String) query.getSingleResult();

我明白了

Hibernate: { ? = call schema.somefunc(?) }
18:21:11.222 [main] WARN  o.h.util.JDBCExceptionReporter - SQL Error: 6550, SQLState: 65000
18:21:11.222 [main] ERROR o.h.util.JDBCExceptionReporter - ORA-06550: Row 1, Column 13:
PLS-00382: This expression has the wrong type
ORA-06550: Row 1, Column 7:
PL/SQL: Statement ignored

javax.persistence.PersistenceException: org.hibernate.exception.SQLGrammarException: could not execute query
at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1389)
at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1317)
at org.hibernate.ejb.QueryImpl.getSingleResult(QueryImpl.java:307)

有什么想法吗？

Answer 1

我们最终使用CallableStatement。它有效，但告诉我是否有更好的解决方案！

String funcCall = "{? = call schema.mypkg.somefunc(?)}";
Connection conn = ((SessionImpl)em.getDelegate()).connection();
CallableStatement stmt = conn.prepareCall(funcCall);
stmt.setInt(2, 42);
stmt.registerOutParameter(1, Types.CHAR);
stmt.executeUpdate();
String result = stmt.getString(1);

Answer 2

我是一个相当hacky的方式，你必须返回一个refcursor。因此，请确保您的函数返回ref游标，并执行以下操作：

result_string := doSoemthing
    open l_refcursor for select result_string as str from dual;
    return l_refcursor;

然后创建一个“虚拟”实体

@Entity
public class NativeString {
    private String str;

    @Id
    @Column(name = "str")
    public String getStr() {
        return str;
    }

    public void setStr(String str) {
        this.str = str;
    }
}

您可以使用本机查询功能

@NamedNativeQueries({
        @javax.persistence.NamedNativeQuery(name = "whatevs", query = "" +
                "{? =  call myfunction(:id)}", resultClass = NativeString.class,
                hints = {
                        @javax.persistence.QueryHint(name = "org.hibernate.callable", value = "true")
                }

        )

})

这就像它得到的一样丑陋......没有很好的方法来支持hierbnate和存储过程和函数。

如何调用使用Hibernate / JPA返回字符串的Oracle函数？

2 个答案: